RykuPrep Study Guide

RykuPrep Study Guide General Cat & Dog Notes 

Heartworm disease is caused by Dirofilaria immitis. o The adult worms produce L1 larvae (microfilariae) inside the bloodstream.  L1 microfilariae mature to L3 larvae inside mosquitoes.  L3 larvae are the infective stage inside cats and dogs.  Heartworm preventives kill L3 & L4 larvae that have accumulated in the animal’s subcutaneous tissue the past month. o Heartworm antigen tests and microfilariae tests only work about 6 months postinfection  It takes ~6 months for the L3s to mature into adults. o Occult infection has adult worms only. Patent infection has microfilariae and can transmit to mosquitoes.  Occult infection would have positive antigen test and negative Knott’s test. o No need testing puppies or kittens for heartworm until 6 months after given preventive.  Use heartworm antigen test in dogs. o Most common sequela of heartworm disease is thromboembolism. Glomerulonephritis is also common due to Ag-Ab complex deposition in kidneys. o Larvae are more likely to migrate to ectopic locations in cats than in dogs. o Treatment for heartworms in dogs includes exercise restriction, doxycycline, monthly preventive, and melarsomine.  Doxycycline kills the Wolbachia bacteria associated with Dirofilaria immitis. o Cats are not the true end-stage host for heartworms and will often kill off any L3s they are exposed to.  Use heartworm antibody test in cats.  Treatment for cats is prednisolone, preventives, and possibly doxycycline.  The two types of microfilariae that can be seen in dog blood are Dirofilaria immitis (heartworm) and Acantheilonema reconditum. Acantheilonema reconditum is non-pathologic and does not need to be treated. Systemic inflammatory response syndrome (SIRS) is associated with the cytokine Interleukin-1. Doberman Pinschers are predisposed to type III hypersensitivity reactions to sulfa drugs (such as TMS). Air bronchograms on a radiograph indicate uniform lung consolidation. Isotonic crystalloid shock dose in dogs is 90 mL/kg. o Isotonic crystalloid shock dose in cats is 40 – 60 mL/kg.

o Give 1/3 shock dose and then reassess. Most cats prefer clumping litter. Feline hairballs are treated with Laxatone. Anticoagulant rodenticides will cause an increase in PT (prothrombin time) before other coagulation times. Lembert, Cushing, & Connell patterns are inversion patterns used to close hollow viscera. o The Bunnel pattern is used to close severed tendons. o The Ford interlocking pattern is used to appose tissues with increased tension. o The horizontal and vertical mattress patterns are eversion patterns. An alveolar radiographic pattern shows areas of consolidation with air bronchograms. Non-cardiogenic pulmonary edema can be caused by electrocution, pulmonary thromboembolism, head trauma, and upper airway obstruction. o Non-cardiogenic pulmonary edema is not caused by hypertension.  Blood makes up 8% of body weight in most species. o Cat blood makes up about 6% of body weight. o In order to raise a PCV by 1%, give 1 ml/kg of packed red blood cells.  A 100% solution is 1 g/mL. o A 1% solution is 10 mg/mL.  2/3rds of body weight is water. o Intracellular fluid makes up 2/3rds of body water (40% of weight) & extracelluar fluid makes up 1/3rd of body water (20% of weight).  RER = 70 x BWkg0.75 o Another equation is RER = 30 x BWkg + 70  Standard chemotherapy affects neutrophils the most because neutrophils have short halflives and replicate quickly. o Chemotherapy targets cells that replicate quickly.  The most common intussusception in small animals is ileocolic.  A 1st degree burn involves the epidermis. o A 2nd degree burn can go down to the dermis. o A 3rd degree burn involves the adnexal structures. o A 4th degree burn involves muscle and bone.  The round ligament of the bladder is a remnant of the umbilical arteries. o The urachus becomes the middle ligament of the bladder. o The umbilical vein becomes the falciform ligament.  In dogs, the dead space associated with aural hematomas are closed with mattress sutures parallel to the blood vessels.  Actinomyces (a filamentous, gram-positive, rod bacteria) is associated with plant awn migration.  In utero infection with feline panleukopenia virus can cause cerebellar hypoplasia. o Feline panleukopenia virus is caused by a parvovirus. o In utero infection with canine parvovirus causes nonsuppurative myocarditis.  Canine parvovirus affects the GI tract and bone marrow (rapidly dividing tissues).

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o Caused by Canine parvovirus-2 o The most affected age group of puppies is 6 weeks to 6 months. o A key finding of Parvovirus is leukopenia. Bordatella bronchispetica is a cause of primary bacterial pneumonia in dogs. o Causes infectious canine tracheobronchitis (kennel cough). Cryptococcus neoformans causes mucopurulent nasal discharge and a proliferation on the nose (Roman nose) in cats. o Can also cause neurologic signs and uveitis (aqueous flare). o Spread via pigeon droppings. o Diagnose with latex agglutination titer or by seeing small yeasts with large capsules on CSF tap. Hemorrhagic gastroenteritis causes bloody diarrhea and an elevated PCV. o Most important therapy is aggressive IV fluids. Rabies protocol for dogs is vaccinate at 3 months, booster one year later, then vaccinate every 1 – 3 years. Rattlesnake bites can cause echinoctyes, thrombocytopenia, prolonged PT/PTT, and unilateral painful muzzle swelling. Perineal hernias are usually seen in older intact male dogs. Keratoconjunctivitis sicca is caused by autoimmune destruction of the lacrimal glands. Causes decreased tear production and mucoid ocular discharge. o Treat with topical cyclosporine and steroids. o A side effect of sulfa drugs is keratoconjunctivitis sicca. Cats can exhibit cervical ventroflexion due to weakness, which is most often caused by hypokalemia. In a dog that has had a parathyroid adenoma removed, monitor the serum calcium daily for a week to check for hypocalcemia. The definitive host for Sarcosystis cruzi is the dog. Vitamin D causes high calcium and high phosphorous. o PTH causes high calcium and low/normal phosphorous. Fleet enemas are high in sodium and phosphate, which causes a hypocalcemia. o Fleet enemas cause hyperphosphatemia, hypernatremia, and hypocalcemia. o Treat with calcium gluconate, IV fluids, and phosphorous binders. Hyperkalemia (increased K+) causes bradycardia, absent P waves, prolonged PR interval, wide QRS complexes, and tented (spiked) T waves. o Can be seen with renal failure. o Treat with:  Calcium gluconate and Calcium chloride are cardioprotective; it does not reduce K+.  NaHCO3 causes an intracellular exchange of H+ for K+.  Glucose and insulin cause a K+ transfer with glucose.  Furosemide promotes renal excretion.

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Acromegaly is caused by excessive growth hormone release due to a pituitary tumor. Causes enlarged head, abdomen, and paws, as well as insulin-resistant diabetes mellitus due to growth hormone causing a defect in insulin receptors. o Diagnose with an MRI. o Best way to treat a pituitary tumor (as seen with acromegaly) is with external beam radiation therapy.  The most predisposed breed to perianal fistulas is German Shepherds. o Causes hematochezia, tenesmus, mucopurulent discharge near anus, and ulcerations around perineum. o Probably immune-mediated and treated with cyclosporine.  Acetaminophen toxicity causes muddy mucous membranes, tachycardia, methemoglobinemia (brown blood), and Heinz body formation. o Cats lack glucuronyl transferase, which is needed to metabolize acetaminophen. o Treat with N-acetylcysteine and abscorbic acid.  Mothballs can cause Heinz body anemia.  Pythium is an aquatic organism common in ponds in the southeast United States. o Extremely difficult to treat. Treat with amputation and systemic antifungal therapy.  Myasthenia gravis causes occasional weakness and megaesophagus. Caused by deficiency of acetyl choline receptors on postsynaptic membrane. o Treat with elevated feedings and pyridostigmine (an acetylcholinesterase inhibitor). o Diagnose with a Tensilon response test. (Tensilon is an anticholinesterase that prolongs the effect of the available acetylcholine.) o Can be seen with a thymoma (which is a cranial mediastinal mass). Feline asthma can present with panting, episodic respiratory distress, exercise intolerance, wheezing, and coughing (which sounds like getting rid of hairballs). o Feline asthma is due to allergens causing a type I hypersensitivity response. o Causes eosinophil infiltration into the lungs. o Causes an expiratory push. o Diagnose with a bronchoalveolar lavage, which show seosinophilic inflammation with mucus.  Radiographs will show hyperinflation of the lungs, a bronchiolar pattern, and atelectasis of the right middle lung lobe. o Treat feline asthma with prednisolone on an anti-inflammatory dose (not immunosuppressive). Use nebulizers or inhalors  Beta-two agonists such as terbutaline would be useful.  Atropine is contraindicated because it thickens bronchial secretions.  Pulmonary thromboembolism can cause dyspnea and split second heart sounds with normal radiographs.  Distemper virus infection in young dogs can lead to enamel hypoplasia. o Dogs 3 – 6 months old are most susceptible to distemper.

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Major differentials for feline upper respiratory tract disease include Chlamydophila felis, Feline calicivirus, & Feline herpesvirus. Classic lesion for Feline Infectious Peritonitis is pyogranulomatous vasculitis. o Diagnose FIP with biopsy and histopathology.  Serology for FIP is unreliable due to cross-reaction with feline coronavirus. 7B protein ELISA test is also unreliable. o Rivalta’s test has the highest negative predictive value (best for ruling out FIP). Linear foreign bodies such as string cause intestinal plication. Lead toxicity has neurologic signs and basophilic stippling of erythrocytes. Treated with Ca-EDTA. o Do not use sodium EDTA. EDTA binds calcium and can cause a hypocalcemia; Ca-EDTA is needed to prevent hypocalcemia. Taurine deficiency in cats cause dilated cardiomyopathy and central retinal degeneration.

Lipomas look like this: . o Lipoma fine needle aspirates typically have a clear and oily appearance.  The most common cause for hypercalcemia in dogs is T-cell lymphoma.  Sertoli cell tumors are endocrinologically active. Sertoli cell tumors make estrogen, cause prostatic metaplasia, and cause contralateral testicular atrophy.  Peripheral nerve sheath tumors (and other soft tissue sarcomas) are locally aggressive and often recur after surgical removal. In dogs, 50% of mammary tumors are malignant. Only 50% of malignant mammary tumors will metastasize. o In cats, > 90% of mammary tumors are malignant. Single solitary liver masses are usually hepatocellular carcinomas. o Remove with surgery and have a long-term survival (~1400 days). Histiocytic neoplasia is most common in Bernese Mountain Dogs.  Perianal adenomas respond to testosterone and often regress with castration. Cutaneous lymphoma causes pruritic lesions of the oral mucosa and foot pads. o Intestinal lymphoma is treated with chlorambucil and prednisolone. Apocrine gland sac adenocarcinoma commonly causes polyuria & polydipsia, secondary to hypercalcemia of malignancy.

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Stargazer lily toxicity causes renal failure in cats.

General Horse Notes   

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Horse’s dry matter should be 12% protein. Normal horse lactate should be < 2.5 mmol/L. Fescue ingestion causes reproductive problems. o Red maple causes Heinz body anemia. o St. John’s wort & pyrrolizidine alkaloids causes photosensitization and hepatotoxicity.  Pyrrolizidine alkaloids cause megalocytosis, fibrosis, & bile duct hyperplasia. o Cantharidin from blister beetles causes colic. o Yellow star thistle toxicity causes nigropallidal encaphelomalacia.  This causes lips to pull back and the tongue to tremor when a horse attempts to eat. o Black walnut contains jugulone, which causes laminitis. o Onions cause hemoglobinuria & Heinz body anemia. Horses are predisposed to gastric ulcers because they constantly secrete gastric fluid. Arabian horses are predisposed to cerebellar abiotrophy. Peritoneus tertius ruptures let you extend the hock and flex the stifle simultaneously. o Ringbone is osteoarthritis of the pastern or coffin joints. o Stringhalt is spastic hyperflexion of the hindlimb and is treated with a lateral digital extensor tenectomy. o Sweeney is shoulder atrophy. o Sweet itch is a type I allergic reaction to Cullicoides. Causes pruritus. Summer sores are caused by Habronema & Draschia stomach worms. Causes eosinophilic granulomas on skin. In horses, the muscle responsible for inspiration is the diaphragm. Proud flesh is exuberant granulation tissue formation at a wound site. African Horse Sickness is spread by Cullicoides flies. Purpura hemorrhagica in the horse is an immune complex disorder associated with high levels of Streptococcus equi ssp. equi antigens and antibodies. o Disrupts endothelial integrity, which causes leaked blood and plasma. o Causes an aseptic necrotizing vasculitis and can cause tissue sloughing. o Treat with dexamethasone and penicillin.

 o Gray horses are predisposed to melanoma, which normally appear in the perineal region.  The most sensitive test for Strangles (Streptococcus equi subsp. equi) is PCR of guttural pouch wash for the S. equi M protein gene. o For Strangles, reintroduce horses 30 days after resolution of signs, then 3 consecutive weekly negative nasopharyngeal cultures (after all that). o Strangles has a similar presentation to the foreign disease Glanders.  Glanders is diagnosed with a Mallein test. Abdominal paracentesis in horses is performed to the right of the midline and normally retrieves yellow fluid. Premature foals have short silky hair coats, pliant floppy ears, soft muzzle, incompletely ossified carpal & tarsal bones, and laxity of flexor tendons. Equines develop marked hyperbilirubinemia from fasting. Nephrosplenic entrapment causes the left kidney to be obscured on abdominal ultrasound. o The spleen may also be difficult to see. o Can use phenylephrine to help treat. Equine eosinophilic granulomas are nodular, non-ulcerative, and are not pruritic. o Treat with systemic antibiotics, sublesional steroids, and surgical excision. Equine Herpes Virus-1 (EHV-1) can cause mares to abort. Future breeding possibilities should be unaffected, although the mare does not have permanent immunity and may be infected again. o Vaccinate against EHV at 5, 7, & 9 months gestation.  Tyzzer’s disease is caused by Clostridium piliformis in mice and foals. o Causes acute necrotizing hepatitis.  Laryngeal hemiplegia is due to a damaged recurrent laryngeal nerve. o Usually affects the left side. o Causes an audible whistling sound on inspiration.  Culicoides flies can cause a type I allergic reaction, extreme pruritus, and self-trauma.  Hyperkalemic periodic paralysis is due to a heritable defect in voltage-gated sodium channels. o This is an autosomal dominant trait.  An auriculopalpebral nerve block lets you examine the eyes of a horse. o This blocks the auriculopalpebral branch of cranial nerve VII (facial nerve). This disrupts the motor innervation to the orbicularis oculi, which closes the eye. o Does not offer any anesthesia. o Perform with lidocaine at the caudal aspect of the zygomatic arch.

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Foal heat diarrhea causes very mild diarrhea in 7 - 14 day old foals. Associated with post-foaling estrous in the mare. o Rhodococcus equi causes diarrhea and respiratory signs in 1 - 4 month old foals.  Rhodococcus equi is gram positive pleomorphic rods.  Causes pulmonary abscesses and an alveolar lung pattern.  Treat with erythromycin and rifampin. o Clostridium perfringens Types A, B, & C causes severe and fatal diarrhea in foals. Most will die within 2 days if not treated. o Rotaviruses are the most common cause of viral diarrhea in foals. Miniature horses are predisposed to hyperlipemia and hepatic lipidosis secondary to anorexia. o Miniature horses are also predisposed to colic due to small colon impaction. This causes a dilated gas-filled colon.  In horses, subsolar abscess result from penetrating wounds or poor farrier work. Causes severe lameness, heat and pain in the affected foot, and edema of the pastern & fetlock. o Treat with adequate drainage, disinfectants, and poultices.  Gastric reflux with a pH > 5 indicates small intestinal obstruction or ileus. The most common equine tumors are sarcoids. o Sarcoids are locally aggressive fibroblastic tumors of the dermis and subcutis with a variable proliferative epithelial component. o Caused by Bovine papillomavirus types 1 & 2. The most common equine bladder and gastric tumor is squamous cell carcinoma. o The most common equine intestinal neoplasia is a lymphosarcoma.  Equine influenza is an orthomyxovirus spread via aerosol.  Choke (esophageal obstruction) is not an emergency; you have time to act. o Most cases of choke resolve within 24 hours without treatment. o Treat by sedating and passing a nasogastric tube to move the obstruction aborally (away from mouth).  Meconium impactions in foals are treated with acetylcysteine enemas.  Windswept foals have valgus of one limb and varus of the contralateral limb.  Normal pCO2 in a horse is 40.

General Ruminant Notes  Normal somatic cells in cows are < 200,000 cells/mL. If you puncture your finger with the RB51 brucellosis vaccine, see a physician and request 3 weeks of doxycycline. o Brucella ovis can cause epididymitis and infertility in rams. Test with ELISA. Salt poisoning, lead poisoning, polioencephalomalacia, and vitamin A deficiency will all cause neurologic disease.

o Vitamin A deficiency is the only disease that will cause absent pupillary light reflexes. Bighead (Clostridium novyi Type A) causes edema of the head and neck. o Treat with wound debridement and penicillin. o No need to cull or isolate affected animals because it is part of the native flora.  Contagious ecthyma is caused by a parapoxvirus. Affects lambs and kids.

o Scabs fall off within 1 month. o Can cause low-grade fever and make animal not want to eat. o Microscopically resembles proliferative granulation tissue.  Bovine papular stomatitis (BPS) is a parapox virus is similar to contagious ecthyma. o Causes fever and raised oral lesions that will resolve in a few weeks. Ovine Progressive Pneumonia (OPP) is a lentivirus of the family Retroviridae and is the most common cause of pneumonia in sheep. Hydroallantois is a disorder of the placenta that results in accumulation of fluid during the last trimester. The cow is clinically affected. o Calf usually dies and the cow usually becomes infertile. Hydramnios is a disorder of the fetus with thick viscous fluid accumulated. The cow is not clinically affected and has a good prognosis for future pregnancies. Blue tongue is an RNA orbivirus that mainly affects sheep, but also cattle. o Causes fever, widespread multisystemic vasculitis, oral lesions, mucopurulent nasal discharge, pulmonary edema, white streaks in muscle, and lameness.  Causes loss of epithelium and edema in the tongue. This can turn the tongue blue.  Blue tongue is a teratogen and can cause abortions.  Causes hydranencephaly (destroyed cerebrum) in lambs born from sheep infected with blue tongue.  Cattle may suffer reproductive losses but rarely show signs of the systemic disease. Aborted or live weak calves can have white eyes due to cataracts. o Spread by the midge Culicoides sonorensis. o Appears similar to Foot and Mouth Disease.  Johne’s disease (Mycobacterium avium spp paratuberculosis) usually affects cows 2 – 5 years old. o Causes enlarged mesenteric lymph nodes and granulomatous bowel. o Johne’s disease is associated with Crohn’s Disease.

Bovine spongiform encephalopathy is associated with Creutzfeldt-Jakob disease. Caseous lymphadenitits is caused by Corynebacterium pseudotuberculosis, which is a pleomorphic, gram positive, intracellular, facultative anaerobic rod. o Best method of prevention is a Corynebacterium pseudotuberculosis vaccine. o Treatment is not usually recommended, so cull. o If treating a valuable animal, surgically drain or remove the abscess. Then isolate and give antibiotics.  Clostridium hemolyticum (renamed Clostridium Novyi type D) causes bacillary hemoglobinuria, internal hemorrhage, and acute death with bloody urine. o Liver flukes (Fasciola hepatica) are often associated with the disease. You can control flukes by controlling snails. o Treat with penicillin or oxytetracycline.  Infectious Bovine Rhinotracheitis is caused by 3 types of bovine herpes virus (BHV). o BHV-1.1 causes respiratory and ophthalmic infections. o BHV-1.2 causes respiratory and genital infections. o BHV-1.3 causes neurologic infections.  Malignant Catarrhal Fever causes acute arteritis, diarrhea, cloudy cornea, fever, respiratory signs, and gastrointestinal lesions. o Wildebeest are the reservoir for the African form & sheep are the reservoir for the North American form.  Enzootic pneumonia is the major respiratory disease of 3 – 8 month old calves. o Multifactorial, but most common cause is Pasteurella multocida. o Causes cranioventral consolidation. o Commonly seen with coccidiosis.  Coccidiosis is a parasitic infection that causes destruction of the intestinal mucosa. o Caused by the protozoa Isospora or Eimeria.  In chickens, coccidiosis is caused by Eimeria. o Causes bloody diarrhea, tenesmus, and dehydration. o Treat with amprolium.  Amprolium has a 0 day meat withdrawal time. o Nervous coccidiosis affects cattle less than 1 year of age due to a neurotoxin.  E. coli O157:H7 is an enterohemorrhagic strain of E. coli that produces Shiga-like toxins. o Causes no symptoms in cows but has zoonotic potential.  Diagnose carriers with stool culture or PCR.  Mycoplasma bovis causes otitis media, respiratory disease, mastitis, arthritis, and abortion. o Cull all cows with Mycoplasma bovis mastitis. o Growth medium for Mycoplasma bovis is Hayflick’s agar.  Mannheimia hemolytica causes fibropurulent bronchopneumonia. o This is the worst bovine pulmonary pathogen.

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Trichomoniasis (Tritrichomonas foetus) in a herd of cows is normally asymptomatic but causes poor calving percentage. o Mature bulls are usually the reservoir for a herd. o Most common cause of pyometra in cows. E. coli is the major cause of diarrhea in 3 – 5 day old calves.  Clostridium chauvoei causes blackleg in cattle.  Campylobacter fetus cannot be spread to humans via milk. o Campylobacter fetus primarily causes early embryonic death and infertility in cows, but it can cause abortion. Left displaced abomasums occur in the first 4 weeks after parturition and are heard from the last to the 8th rib. o Normally have normal vital signs. Cattle have 11 blood groups. o Horses and sheep have 7 blood groups. o Goats have 5 blood groups.  White muscle disease is caused by selenium deficiency. Causes white streaks in muscle and can cause sudden death due to myocardial abnormalities. o Check for selenium deficiency by testing for glutathione peroxidase.  Moldy sweet potatoes have 4-Ipomeanol, which causes atypical interstitial pneumonia. o Perilla mint has perilla mint ketones, which are toxic to the respiratory system. o Brassica plants (associated with lush pasture) have D,L-tryptophan, which is converted in the rumen into 3-methylindole. This causes pulmonary edema and emphysema o Moldy sweet clover contains slaframine, which causes hypersalivation. It also causes a coagulopathy via inhibiting vitamin K. o Castor bean results in hemolysis. o Yellow bristle grass has barbs that cause oral ulcerative damage. o Amaranthus contains nitrates, which causes chocolate brown blood and weakness. o Cottonseed has gossypol, which can cause dyspnea, weakness, reproductive problems, and death in calves via cardiomyopathy.  Spider lamb syndrome is a genetic disease of sheep that causes carpal valgus.  Postparturient hemoglobinuria is due to hypophosphatemia below 2.0 mg/dL.  Float tanks are the most effective way of managing down cows without underlying fixable problems.  Milk liners last at least 500 milkings.  Streptococcus agalactiae is not an environmental mastitis organism; it is contagious. o This is the only mastitis organism that responds to treatment during lactation.  Best way to combat failure of passive transfer in calves past effective colostral supplementation (older than 2 days) is to give IV bovine plasma. o Best way to test for failure of passive transfer is ELISA (SNAP) test.  A DCAD diet uses the formula DCAD = (Na + K) - (Cl + S)

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Obese cows are predisposed to fatty liver syndrome when they encounter a negative energy balance.  Spastic paresis is a hereditary disease that causes continuous stiffness of the hocks (tibiotarsal joint). o Treat with gastrocnemius tenectomy.  Volcanic soils often cause copper deficiency.  Sheep are very prone to copper toxicity, which causes a hemolytic crisis. o Cattle feed is a common source of copper toxicity.  Uterine prolapses occur immediately postpartum. o Vaginal prolapses occur late in pregnancy. o Rectal prolapses are associated with straining to defecate.  Femoral nerve paralysis in calves causes the inability to bear weight on pelvic limbs and dog sitting without bony abnormalities. o Prevent in the future with delivery via Cesarean section.  In order to do a standing laparotomy in a cow, you must perform a paravertebral nerve block to desensitize nerves T13, L1, & L2.  Pododermatitis circumspripta involves a lesion in the sole/bulb junction. With sole abscesses in cows, put wooden hoof block on claw that is not affected.  Lice are usually species-specific and have 6 legs. o Mallophaga are biting lice. o Anoplura are sucking lice that can cause anemia.  Poloxalene will destabilize froth and help cure bloat.  The most common ocular tumor of cattle is squamous cell carcinoma. Ocular squamous cell carcinoma has a heritable and sunlight component. o Euthanize beef cattle with lymphoma or squamous cell carcinoma because they cannot be eaten. o If you do surgically remove the eye, use a five-point orbital block using lidocaine.

General Pig Notes Pseudorabies is reportable, transmitted via inhalation, and causes these signs: o Neurological signs in piglets. o Neurological & respiratory signs in weaned pigs. o Respiratory signs in older pigs. o Reproductive failure in pregnant sows.  Inguinal hernias in pigs are heritable. o Inguinal hernias are most common in males after castration. o Umbilical hernias are slightly more common in female pigs.  Staphylococcus hyicus causes greasy pig disease in piglets under 2 months old.  Streptococcus suis causes polyserositis and sometimes pneumonia.  Actinobacillus pleuropneumoniae is the most common cause of sudden death in pigs.

o Causes pink and frothy oral and nasal discharge. o Immediately treat all pigs in herd with enrofloxacin.  Classic Swine Fever causes splenic infarcts. o African Swine Fever is similar to Classic Swine Fever.  Herpes viruses become latent in the trigeminal ganglia where they become incorporated in the host genome. o There is no antibody response during latency.  Salt poisoning causes neurological signs in pigs. Major indicator is perivascular infiltration of eosinophils.  Swine tuberculosis is associated with materials contaminated by birds.  Vitamin A deficiency can cause ataxia, head tilt, and middle ear infections. Fusobacterium necrophorum contributes to necrotic rhinitis in pigs.  Rectal strictures and large intestinal ulcers are a common sequela to salmonellosis.  Vesicular stomatitis is caused by a Rhabdovirus. Vesicular stomatitis is a reportable disease with signs similar to foot-and-mouth disease. Is present in the U.S. o Foot-and-mouth disease is caused by a picornavirus.  Zearalenone is a mycotoxin that causes hyperestrogenism, pseudopregnancy, and rectal prolapse in pigs. o Alfatoxins cause hepatic necrosis and fibrosis.  Enterotoxogenic E. coli produces a heat-stable Shiga toxin. This causes facial edema, diarrhea, dyspnea, and circling.  Hemolytic E. coli is treated with ceftiofur injections for sick pigs and gentamycin in the water. o F18 E. coli is associated with edema disease in swine.  Brucellosis causes abortion at all gestational stages without placental lesions. o Brucellosis is present in feral swine and spread venereally and through aborted fetuses.  Parvovirus causes mummies and stillborns, not abortions.  Atrophic rhinitis is caused by Bordatella bronchiseptica & Pasteurolla multocida. o Bordatella causes non-progressive atrophic rhinitis. o Pasteurella causes progressive atrophic rhinitis. o No treatment, just cull.  Pityriasis rosea causes raised circular lesions on the ventral abdomen of 3 – 14 week old pigs. o No treatment required.  Erysipelothrix rhusiopathiae causes diamond-shaped lesions, is treated with penicillin, and has 3 forms: o The peracute form causes sudden death. o The acute form causes lethargy, painful joints, abortion, and diamond-shaped skin lesions. o The chronic form has vertebral arthritis and limb joint fusion.

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Clostridium perfringens type C enteritis causes acute hemorrhagic diarrhea and death in piglets up to 1 week-old. o High morbidity and mortality.  Enteric colibacillosis (enterotoxogenic E. coli) causes diarrhea in piglets up to 2 weeksold, but is not bloody and does not cause death. Coccidiosis in pigs (Isospora suis) causes high morbidity and low to moderate mortality. o Affects 1 – 3 week old piglets. o Not responsive to antibiotics. o Best prevention is improved sanitation.  Transmissible gastroenteritis is caused by a Coronavirus. It causes diarrhea and complete mortality in piglets less than 2 weeks-old. o Causes mild diarrhea in older pigs.  Swine dysentery (Brachyspira hyodysenteriae) causes bloody diarrhea and death in grower and finisher pigs.

General Exotic Notes The best site for tuberculosis testing in monkeys is intradermally in the 3rd eyelid. Raccoons carry the zoonotic diseases Rabies & Baylisascaris. o Baylisascaris is a roundworm that can cause CNS signs in humans. Choanal atresia in alpacas is a congenital disorder causing a lack of an opening between the nasal and pharyngeal regions. o Causes respiratory signs. o Commonly seen with other congenital abnormalities such as extra digits. BIRDS: o Marek’s disease in chickens is caused by a herpes virus.  Causes sciatic nerve paralysis and brain edema. o Metabolic dystocia in birds (egg binding) can be caused by hypocalcemia. Treat with calcium gluconate.  Diagnose with radiographs. o In birds, the pectin is a normal black structure from the retina to the vitreous humor.

o Budgerigars that look like this have the genetic disorder Chrysanthemum disease.  Continuous growth of feathers all over body.

o In birds, progressive unilateral paralysis is usually due to renal neoplasia (due to pressure on sciatic nerve).  Diagnose with abdominal radiographs. o Egg drop syndrome is caused by an adenovirus.  Causes healthy birds with soft-shelled or no-shelled eggs that are eaten by other birds. o Hypovitaminosis A in birds is seen with all-seed diets. Causes squamous metaplasia and white plaques in the oral cavity.  All-seed diets can also cause hypocalcemia, which can lead to cloacal prolapse. o Chickens commonly develop Candidiasis (Candida albicans) after the use of antibiotics.  Causes thickened mucosa and circular oral ulcers.  Treat with copper sulfate or nystatin. o The best treatment for feather cysts is surgical removal of cyst and follicle. Feather cysts are like ingrown hairs.

 o Heavy metal toxicosis causes PU/PD, severe dehydration, and hemoglobinuria.  Liver disease can present similarly but has green-tinged feces. o Eclectus parrots are sexually dimorphic.  Males are green & females are yellow. o Male birds are ZZ and female birds are ZW.  Male mammals are XY & female mammals are XX. o Toucans and mynah birds are susceptible to hemochromatosis (iron storage disease). Causes poor feathering, overgrown beak, and elevated liver enzymes & bile acids.  Diagnose with liver biopsy. o Psittacine beak and feather disease usually affects psittacine birds >> ALT, consider muscle damage and evaluate creatinine kinase (which is muscle specific). o ALP is increased with cholestasis. More specific for cholestasis but not as elevated in cats.  Glucocorticoids cause an increase in ALP in dogs. o GGT is increased with cholestasis. More specific for cholestasis in dogs. o Albumin is only made in the liver. Liver failure will have hypoalbuminemia. o BUN is decreased with liver failure. o Hypocholesterolemia will be seen with liver problems.  Hypercholesterolemia will be seen with decreased biliary excretion of cholesterol (extrahepatic obstruction). o Unconjugated bilirubin is processed from heme and conjugated in the liver.  Pre-hepatic hyperbilirubinemia will have increased conjugated bilirubin.  Hepatopathy will have increased unconjugated bilirubin. o Sorbital dehydrogenase (SDH) is the most liver-specific enzyme in ruminants and horses. Tuberculosis is an infectious granulomatous disease that primarily affects the lungs. o It is usually caused by Mycobacterium species. o The most important diagnostic test is the intradermal tuberculin test.  False positives are expected because there is cross-reactivity with other mycobacteria.  Antigens are injected into the skin. If an animal has experienced the bacteria than they should mount an immune reaction. o Humans usually get an airborne infection.  There is not good zoonotic transfer from animals because the infection is not usually spread via aerosols. Most common primary brain tumors in dogs are oligodenrogliomas & astrocytomas. o The most common primary brain tumors in cats are meningiomas.

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Agglutination of erythrocytes is due to immune-mediated hemolytic anemia (IMHA). o Spherocytes are small and round erythrocytes that also indicate IMHA.

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 Reticulocytes are large, dark blue, young erythrocytes.

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o o Indicate a regenerative anemia. o Horses do not release reticulocytes. Heinz bodies indicate oxidative damage.

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(new methylene blue stain)

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Howell-Holly bodies are nuclear remnants and may indicate increased erythropoiesis.

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o Acanthocytes can indicate hemangiosarcoma.

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o Macrocytosis is large erythrocytes and is usually seen with regenerative anemias. o Microcytosis is usually seen with hepatic disease, portosystemic shunts, and iron deficiency. Toxic neutrophils indicate intense neutrophil production and shortened maturation time. A left shift is an increase in immature (band) neutrophils. o A regenerative left shift is a mature neutrophilia with smaller numbers of band neutrophils. o A degenerative left shift means there are more immature band neutrophils than mature neutrophils. Glucocorticoids cause SM¡LE. o Increased segmented neutrophils and monocytes. o Decreased lymphocytes and eosinophils. Epinephrine causes increased in neutrophils and lymphocytes. Disseminated Intravascular Coagulation (DIC) is not a primary disease but secondary to underlying diseases. o The underlying disease causes an uncontrolled systemic inflammatory response characterized by massive activation and consumption of coagulation proteins, endogenous inhibitors, fibrinolytic proteins, and platelets. o Usually induced by exposure to tissue factor and activation of the extrinsic pathway of coagulation. o DIC causes a decrease in fibrinogen because it is utilized. Normal cavity fluid should be a transudate (low protein and cells). o To distinguish a septic exudate from a normal exudate, look for intracellular bacteria. Pathogenic hemorrhage is indicated by phagocytosis of erythrocytes by macrophages. Benign neoplasms have uniform cell appearance, whereas malignant neoplasms have variable cell appearance. Carcinomas are malignant neoplasms that arise from epithelial cells of glandular tissue. o Cytologically, carcinomas appear as clusters of epithelial cells. Sarcomas are malignant neoplasms of mesenchymal cells. o Cytologically, sarcomas appear as solitary spindle cells. Round cell tumors include mast cell tumors, lymphoma, plasma cell tumors, histiocytic tumors, and transmissible venereal tumors.

o Cytologically, round cell tumors appear as large populations of cells not in defined clusters. o Lymphomas are malignant neoplasms of lymphocytes.  Cytologically, lymphoma contains many immature lyphoblasts.  Plasma cells are lymphocytes that secrete large volumes of antibodies. A canine platelet has a circulating lifespan of 5 - 7 days. o Canine leukocytes have a circulating lifespan of 5 - 9 hours. o Canine erythrocytes have a circulating lifespan of 110 days. o Feline erythrocytes have a circulating lifespan of 68 days.  Large amounts of fibrin in fluid indicate the fluid is inflammatory.

Parasites Lice have 6 legs; ticks and mites have 8 legs. Fecal sedimentation is good for testing for eggs that sink, like most fluke (flatworm) eggs. o A direct fecal smear can find any egg or larva passed in feces, but it doesn’t increase the concentration of the parasites. Haemonchus contortus is the most important goat parasite. o The “barber pole” nematode that causes anemia. Strongyloides stercoralis is a roundworm that causes mucoid diarrhea and anemia in puppies and kittens. o Diagnose with the Baermann fecal technique. Moniezia are tapeworms of cattle.

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o rectangular or triangular eggs Trichomoniasis (Tritrichomonas foetus) in cats is a protozoal infection that causes large bowel diarrhea. o Affects young cats who will grow out of the infection without treatment. o Treat with Ronidazole. Aerostrongylus abstrusus is the lungworm of cats and is treated with ivermectin or fenbendazole. Neospora caninum is a protozoan parasite that causes abortion in cows and neurologic & muscular abnormalities in dogs.

Urinary System The upper urinary tract consists of the kidneys and ureters. o The lower urinary tract consists of the bladder and urethra. A nephron is the functional renal unit. A nephron consists of a glomerulus and a tubule. o Glomerular diseases result in proteinuria and eventual tubular disease. o Tubular diseases result in loss of concentrating ability & eventually azotemia. Uremia is not a laboratory value. It is a set of clinical signs seen with kidney disease. Includes vomiting, lethargy, anorexia, weight loss, dehydration, diarrhea, and oral ulceration. o One possible sign of uremia is gastric ulceration. Treated with:  Famotidine - H2 blocker (blocks HCl acid production)  Omeprazole - proton pump inhibitor  Sucralfate - cytoprotective agent (binds to ulcer site) Dogs must lose 65% renal function to become unable to concentrate urine & 75% renal function to see azotemia. o In cats, 75% of renal function must be lost to lose concentrating ability. Polydypsia is > 100 mL/kg/day. o Polyuria is > 50 mL/kg/day. Pollakiuria (frequent urination with small volume), dysuria, and stranguria (straining drop by drop) are signs of lower urinary tract disease. The kidneys excrete H+, phosphorous, potassium, and BUN / creatinine. o Problems with urinary excretion result in metabolic acidosis, hyperphosphatemia, hyperkalemia, azotemia, and hypocalcemia (secondary to hyperphosphatemia). o With chronic renal failure, the body’s compensatory mechanism to hyperphosphatemia is secondary hyperparathyroidism.  Parathyroid hormone (PTH) increases calcium and decreases phosphorous. Blood Urea Nitrogen (BUN) is formed in the liver from metabolism of ammonia. o BUN is the best measure of liver function and also shows kidney function.  High BUN means GFR is low and kidneys are not working. Low BUN means liver is not producing it. BUN does not exceed normal value until 75% of kidney function is lost. Azotemia is high levels of BUN and/or Creatinine in the blood. o Azotemia can be due to decreased GFR (prerenal, renal, or postrenal), high protein diet, GI hemorrhage, steroids, or tetracyclines. o Elevated creatinine is more specific for decreased GFR than elevated BUN. The only other cause of elevated creatinine is well-muscled dogs. Proteinuria can be due to glomerular disease, post-renal hemorrhage or inflammation, or protein overload. o Examples of glomerular disease include glomerulonephritis and amyloidosis.

Amyloidosis is accumulation of inappropriately folded proteins in glomerulus. Amyloidosis results in a gray and waxy kidney. Shar-Peis are predisposed to amyloidosis. o Protein itself is damaging to renal tubules, so proteinuria is a sign of ongoing renal damage. The best measure of glomerular filtration rate is serum creatinine. Urine specific gravity evaluates renal tubular function. o In healthy hydrated animals, the USG can vary widely from 1.015 – 1.050 in dogs to 1.015 – 1.060 in cats. o Consistent isosthenuria (USG 1.008 – 1.012) indicates renal dysfunction. o In the presence of azotemia, the USG should be >1.030 in dogs & > 1.040 in cats. This indicates the kidneys can concentrate urine in the face of decreased blood flow and the azotemia is likely pre-renal.  In the presence of azotemia, a lower than normal USG indicates the kidneys cannot concentrate urine and the azotemia is renal in nature. (Prerenal azotemia may still contribute.) o Cannot evaluate USG once patient is on fluid therapy. One sign of chronic renal disease is a non-regenerative anemia. Ethylene glycol in transformed in liver by alcohol dehydrogenase into the toxic glycolic acid. o Treatment is 4-MP or ethanol, which inhibit alcohol dehydrogenase. o 3 stages of disease: neurological signs  improvement  fatal kidney failure o Will see calcium oxalate crystalluria. Leptospirosis spreads through urine and causes acute renal failure. o Not clinically important in cats. o Diagnosis is via urine PCR or microscopic agglutination test (MAT).  Can be viewed under dark field microscopy. o Vaccination reduces clinical signs but does not prevent infection. o Treat with doxycycline or penicillins. o The most important problem of Leptospirosis in pigs is reproductive failure. All aminoglycosides are nephrotoxic. o Decrease risk with larger single doses. Most common cause of chronic renal failure in small animals is tubuloinsterstitial nephritis. o The most common cause of chronic renal failure in horses is glomerulonephritis.  In horses, glomerulonephritis is treated with corticosteroids, plasma transfusion, & low-protein diet. Glomerulonephritis usually causes polyuria, so furosemide is not needed. Furosemide is indicated for oliguric renal failure. Treatment for chronic kidney disease includes: o unlimited water / wet food 

renal diet with decreased protein and phosphorous Phosphorous binders such as aluminum hydroxide. give calcitriol (activated vitamin D) because the kidneys activate vitamin D Give angiotensin converting enzyme (ACE) inhibitors (Enalapril) to reduce proteinuria. o Reduce hypertension with ACE inhibitors in dogs and Amlodipine in cats. o erythropoietin to correct anemia o Famotidine, omeprazole, or sucralfate to correct gastritis and gastric ulceration o Metoclopramide, dolasetron, ondansetron, or maropitant if vomiting a lot. Renal failure can cause PU/PD, decreased appetite, and weight loss. Protein-losing nephropathies (such as glomerulonephritis and amyloidosis) is treated with dietary protein restriction, ACE inhibitors, and aspirin. o Dietary protein restriction obviously decreases proteinuria. o ACE inhibitors decrease proteinuria by causing dilation of the efferent arterioles. o Aspirin decreases platelet function to help alleviate the hypercoagulable state from lost antithrombin III. Unless obstructed, lower urinary tract disease (LUTD) rarely results in systemic signs or bloodwork changes. o Most common cause of LUTD in dogs is bacterial infections. o Most common cause of LUTD in cats is Feline Idiopathic Cystitis (FIC)  Acute and chronic FIC will usually resolve on own without treatment but may recur.  Treat acute FIC with high-moisture urinary diets and short-term opioids for analgesia.  Treat chronic FIC with same as acute, but also Amitriptyline. The terminal urethra is not sterile; finding microbes in the terminal urethra does not mean there is a urinary tract infection (UTI). o Bacteriuria and pyuria (leukocytes in urine) does not by themselves necessarily mean there is a UTI. o The most common cause of a UTI is E. coli.  Staphylococcus, Enterococcus, Streptococcus, Proteius, Pseudomonas, and Klebsiella are other common pathogens. o Dipsticks are not appropriate for diagnosing a UTI. You must examine a urine sediment and ideally perform a urine culture. o 2 weeks of Amoxicillin is best initial therapy for UTIs. Fanconi syndrome is a form of renal failure normally only seen in Besenji dogs. o Due to a proximal tubule dysfunction. Polycystic Kidney Disease is the most common genetic renal disorder. o Primarily seen in Persian cats and will cause chronic renal failure. o Diagnose with ultrasound. o Treat like any other chronic renal failure case. o o o o

Struvite uroliths are normally sterile in cats and normally associated with bacterial infection in dogs. o You want an acidifying diet to treat struvite uroliths. o Other types of uroliths require an alkalinizing diet to prevent. o Dalmatians are prone to ammonium urate stones.  Dalmatians have a genetic defect in making allantoin from urates in the liver. This predisposes them to forming urate stones and getting urinary tract obstructions.  Treat stones with allopurinol and a low-purine diet to alkalinize the urine.  Allopurinol therapy in turn predisposes Dalmatians to Xanthine stones. o Struvite and calcium stones can be seen on radiographs. Urate and cysteine stones cannot. o Most equine uroloiths are calcium carbonate and calcium phosphate.  The most common urolith in ferrets is sterile struvite. Phenylpropanolamine is an alpha-adrenergic agonist that treats urethral sphincter mechanism incontinence. o Phenylpropanolamine is used to treat dogs who leak urine. Phenoxybenzamine is used to treat hypertonicty of urethral muscle. A uroabdomen will have hyponatremia, hypochloremia, hyperphosphatemia, and azotemia. o Urine is high in potassium and low in sodium & chloride; the electrolytes equilibrate with the blood. A key finding of pyelonephritis is bacterial or leukocyte casts in urine. Urethral obstruction commonly causes hyperkalemia. 0.9% NaCl is the best fluid to treat this. o During the immediate post-obstructive period, cats may develop hypocalcemic tetany. Urohydropropulsion is the expulsion of cystic calculi after anesthetizing an animal by application of manual pressure to the bladder to expel the stone through the urethra. o Best done in thin female dogs. Not done in male dogs because their long, narrow urethras and os penis increase the likelihood of obstruction. Protein-losing nephropathies are treated with ACE-inhibitors, low protein diets, & aspirin (to decrease hyper-coagulable state). No antibiotics are given. Treatment for urethral prolapse is urethropexy and castration. Most often seen in English bulldogs. Myoglobinuria is characterized by brownish urine that does not clear on centrifugation with normal-colored plasma. o Myoglobin doesn’t bind to serum proteins, so it is cleared to the urine before it builds up and discolors the plasma. Check if fluid is urine by comparing creatinine to serum. Fluid:serum creatinine ratio of greater than 2:1 is indicative that the fluid is urine.

Hypoproteinemia can cause low serum calcium but is not associated with clinical signs of hypocalcemia. o Serum chemistry measures calcium bound to proteins. o The accurate measure of calcium is ionized calcium (iCa). Iguanas in renal failure can have episcleral injection, swelling of the pharyngeal region, and painful abdominal palpation.

Cardiology Blood pressure = total peripheral resistance * cardiac output o Cardiac output = heart rate * stroke volume  Eccentric hypertrophy is an increase in cardiac mass with an increase in chamber size. Seen with diastolic stress. o Concentric hypertrophy is an increase in cardiac mass with no change or a decrease in chamber size. Seen with systolic stress.  Patients with compromised cardiac output have exercise intolerance, decreased growth, or muscle wasting. Pale mucous membranes, weak pulses, cold extremities, low temperature. o Patients with right-sided backward failure (congestive failure) have ascites (in dogs) or pleural effusion.  Will see ventral or brisket edema, true jugular pulse, and bottle jaw in large animals. o Patients with left-sided backward failure (congestive failure) have coughing, exercise intolerance, and sleeps in sternal recumbency.  Heart sounds: o S1 is closure of AV valves (ventricles are filled with blood).  S1 indicates beginning of systole. o S2 is closure of semilunar valves (aortic and pulmonary valves; ventricles are empty of blood).  S2 indicates beginning of diastole. o A gallop rhythm is when you hear either S3 or S4, which are diastolic sounds. This is normal in large animal species but indicates pathology in small animal species.  S3 is passive ventricular filling (mid-diastole).  S4 is active atrial contraction (end of diastole).  On the left side, remember P-A-M o 3rd intercostal space you can hear the pulmonic valve (right ventricle pumping into the pulmonary artery) o 4th intercostal space you can hear the aortic valve o 5th intercostal space you can hear the mitral valve

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On the right side, you can hear the tricuspid valve. There is a weak (but existent) relationship between murmur grade and clinical severity. o Innocent puppy murmurs go away by 4 months. o Diastolic murmurs are uncommon; the most common diastolic murmur is aortic regurgitation.  Aortic regurgitation is flow of blood from aorta into left ventricle during diastole.  Will not have effect on athletic performance of a horse. o Holosystolic murmurs are heard throughout all of systole. Indicate mitral regurgitation, tricuspid regurgitation, or ventricular septal defect.  Most common holosytolic murmur is mitral regurgitation. This is heard at the left apex. Due to endocardiosis, degeneration, dysplasia, or dilated cardiomyopathy.  Tricuspid regurgitation is heard on the right. Can be due to endocardiosis, dysplasia.  Mitral or tricuspid valve regurgitation is when blood flows back into the atrium when the ventricles contract. o These lead to eccentric hypertrophy because the chamber must get bigger to pump more blood (because some is wasted). Puts patient at risk for congestive heart failure.  Ventricular septal defect is heard on the right and a little cranial.  Ventricular septal defects are the most common congenital cardiac anomaly in all species except dogs. o Ejection murmurs are heard at the left base.  Indicate aortic stenosis, pulmonic stenosis, or atrial septal defect. o A continuous murmur is usually a patent ductus arteriosus. o Don’t give corticosteroids to patients with undiagnosed heart murmurs.  Steroids can push patients with heart disease into heart failure. Blood flow shunts (such as a ventricular septal defect) go from high pressure to low pressure. So, they are normally left  right. Patent Ductus Arteriosus (PDA) is commonly seen in small, white, female dogs. o The ductus arteriosus directs blood from the pulmonary artery to the aorta in the fetus. o A PDA has blood flowing from the aorta to the pulmonary artery (due to higher pressure in the aorta). o Causes enlarged pulmonary vasculature and left side of the heart, continuous murmur at left base, bounding arterial pulses, and increased QRS amplitudes. o Treated with catheter-based occlusion or surgical ligation.  Surgical ligation is preferred for cylindrical PDAs. Subaortic stenosis is seen in large breed dogs. o Causes systolic murmur at left base, possibly with weak femoral pulses.

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o Fair prognosis, increased risk for infective endocarditis, and sudden death may occur at any time. o Treated medically with Atenolol (beta-blocker). Pulmonic stenosis is seen in smaller breed dogs. o Has a systolic murmur at left base with normal pulses. o May cause right heart enlargement. o Treat with balloon valvuloplasty +/- Atenolol (beta blockers) Carina elevation is the best radiographic estimation of cardiomegaly. o Carina should be 1/3rd - 1/4th of the chest width from the spine. On radiographs, the cranial part of the heart is the right side. The caudal part of the heart is the left side. A vertebral heart score measures the heart cranio-caudal and dorso-ventral. Measure the lines against the T4 vertebrae. Should be < 10.5. When looking at pulmonary vasculature: o big pulmonary arteries = pulmonary hypertension o big pulmonary veins = left-sided congestive heart failure o big pulmonary arteries and veins = left-to-right shunt o small pulmonary arteries and veins = right-to-left shunt or hypovolemia Tetralogy of Fallot is the most common defect that produces cyanosis. It has four components: pulmonic stenosis, large ventricular septal defect, right ventricular hypertrophy, & dextropositioning (overriding) of the aorta. o Results in a right-to-left shunt, hypoxemia, cyanosis, and polycythemia. o Treat with surgery and non-selective beta blockers.

An ECG measures electrical, not mechanical, activity: o P wave is atrial depolarization.  QRS is ventricular depolarization  T wave is ventricular repolarization. o When positioning leads, remember Green & White are always right. Also red and green go at the end of the dog (Christmas colors at end of the year).  White is right front leg.  Green is right rear leg.  Black is left front leg.  Red is left rear leg. o Tall p waves indicate right atrial enlargement.  Wide p waves indicate left atrial enlargement.  Deep S waves indicate right ventricular enlargement.  Tall R waves indicate left ventricular enlargement.

o Pericardial effusion can cause electrical alternans, which is varying height of every other R wave.  Pericardial effusion also causes pulsus paradoxus, which is a much stronger pulse on expiration. o Hyperkalemia (increased K+) causes bradycardia, absent P waves, prolonged PR interval, wide QRS complexes, and tented (spiked) T waves.  Often seen with hypoadrenocorticism or urinary-blocked animals. o Sick sinus syndrome is sinus arrest (arrest of SA node) that lasts several seconds and can cause syncope. 

 Will see several seconds of absence of electrical activity.  Treat with Theophylline or Terbutaline. st o 1 degree AV block has a prolonged PR interval.  Normal PR interval in cats is 0.05 – 0.09 seconds.  2nd degree AV block has more P waves than QRS complexes.  Mobitz I 2nd degree AV block has the PR interval progressively lengthen. o Better for patient and normal in horse.  Mobitz II 2nd degree AV block has the PR interval constant. o

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o Don’t treat type II AV block unless patient is clinical. 3 degree AV block has dissociation between P waves and QRS complexes.  rd

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Treat high-grade AV block with a pacemaker. Never give lidocaine because it may abolish the ventricular escape rhythm.

o Ventricular Premature Complexes have wide and bizarre QRS complexes with AV dissociation (no associated P waves).  Wide and bizarre QRS complexes are almost always VPCs.  VPCs are more deadly in the short-term than supraventricular VPCs.  Narrow QRS complexes with associated P waves are supraventricular premature complexes.  Arise from irritated regions of ventricles.  Ventricular rhythms are more life-threatening than supraventricular rhythms.  Treat ventricular arrhythmias with lidocaine (Sodium channel blocker).  Lidocaine is not useful for supraventricular tachycardia  A string of VPCs in a row is called ventricular tachycardia.  Treat ventricular tachycardia with procainamide, lidocaine, or defibrillation in drug-resistant cases. 

 The “N”s above are some normal beats. o Atrial Premature Complexes look normal but have short R-R intervals.  The beat comes earlier than other beats.  A string of APCs is called atrial tachycardia.  Not concerning in a horse. 

o Atrial fibrillation causes tachycardia, sounds like “tennis shoes in a dryer,” and has an irregular ECG with absent P waves.  Causes “flutter-like” waves. 

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Most common rhythm disturbance in horses.

Causes a rapid irregular heart rate with no atrial sounds or compensatory pause.  Treated with Quinidine (Na+ channel blocker). Sinus arrhythmia is a gradual increase and decrease in heart rate associated with respiration. Atrio-Ventricular Valve Dysplasia o Mitral valve dysplasia is the most commonly affected valve in cats. o Tricuspid valve dysplasia is the most commonly affected valve in dogs, especially Labrador retrievers. o Often causes regurgitation, but can also cause stenosis.  systolic murmurs are heard with regurgitation  diastolic murmurs are heard with stenosis o Can cause atrial hypertrophy o No easy treatment for stenosis. Treat regurgitation with diuretics, ACE-inhibitors, and beta-blockers. Dilated Cardiomyopathy mainly affects larger dogs like Dobermans. o Patient may be syncopal or have congestive heart failure. o Causes markedly dilated ventricles with thin walls that can’t contract well; usually the left ventricle.  Commonly has secondary mitral regurgitation. o Commonly causes premature ventricular contractions and/or atrial fibrillation. o If patient is hypotensive, treat with dobutamine. o In cats, DCM is due to taurine deficiency and cats can also present with retinal lesions. o Treat with ACE-inhibitors even in asymptomatic animals.  Treat symptomatic patients with Pimobendan.  Pimobendan is a positive inotrope and a vasodilator. o Makes the heart beat more efficiently and reduces vascular resistance against the heart. Boxer Cardiomyopathy is similar to dilated cardiomyopathy but has severe and life threatening PVCs or ventricular tachycardia. o Patient may have fainting. o Treat with Solatol and Mexilitene. Hypertrophic Cardiomyopathy is a genetic feline disease seen often in Maine Coons. o Unlike with dilated cardiomyopathy (systolic disease), hypertrophic cardiomyopathy is a diastolic disease that has problems filling. o Aim of treatment is to improve diastolic filling by decreasing heart rate. o Usually have left ventricular concentric hypertrophy. o Usually seen in cats < 3 years-old o Will have systolic murmur and gallop heart sounds. o Treat symptomatic cats with Atenolol (beta-adrenergic blocker), ACE-inhibitors, diltiazem (calcium channel blocker), and heparin (to prevent thromboembolism) 

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Thromboembolism in cats has acute hindlimb paresis; high CK, AST, & ALT o Normally due to blood stasis in large left auricle (atrial appendage). o Treat with heparin and analgesics. Recurrence is common. Endocarditis (inflammatory heart valve disease) is normally secondary to another primary infection. o Usually has an irregularly shaped “growth” on the valve. o In dogs, most commonly affects mitral and aortic valves (left side). o In large animals, most commonly affects tricuspid and pulmonary valves (right side). Hypertension is treated with Enalapril (ACE-inhibitor) in dogs and Amlodipine (calcium channel blocker) in dogs and cats. Most common neoplasia in the heart is right atrial hemangiosarcoma, which can first prevent with pericardial effusion. o Chemodectomas (aortic body tumors) occur in brachycephalic breeds. o Lymphoma infiltrates the myocardium in cattle. Treat supraventricular tachycardias with Atenolol or Digoxin. o The most common supraventricular tachycardia is atrial fibrillation. Normal central venous pressure is 0 - 10 cmH20 o A large increase in central venous pressure (> 12 cmH20) indicates ascites. The most common vascular ring anomaly resulting in constriction of the esophagus in dogs is a persistent right 4th aortic arch. o Treat with surgical resection of the ligamentum arteriosus. Congestive heart failure is treated with oxygen (in-hospital), Furosemide, ACE-inhibitors, and Pimobendan. o Pimobendan is a positive inotrope that increases myocardial contractility. o Causes a modified transudate pericardial effusion. Atrial septal defects can include a patent foramen ovale. o Usually left  right and cause a functional pulmonic stenosis (due to right ventricular overload). o Causes right ventricular hypertrophy and pulmonary vasculature enlargement. o Do not need to close a small, uncomplicated atrial septal defect. o In horses, failure of closure of the foramen ovale results in a right atrium  left atrium shunt. Ventricular septal defects are the most common congenital cardiac defect in all species except dogs. o Cause a holosystolic murmur heard on the right sternal border. o Usually occur just below the pulmonary valve, so the right heart does not see much of an increase in blood and therefore does not have hypertrophy. o Causes enlargement of left heart and pulmonary vasculature. o Treat with pulmonary artery banding. This causes pulmonic stenosis, increases right heart pressure, and lessens the shunt. The most common cause of cardiac arrest in dogs is systemic hypoxemia.

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Ventricular tachycardias are more life-threatening than supraventricular tachycardias. o Supraventricular tachycardias may progress to atrial fibrillation and cause progressive left ventricular dysfunction, which is not immediately lifethreatening. o Ventricular tachycardias may lead to ventricular fibrillation, which can be quickly fatal.

Dermatology 

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Sarcoptes scabiei is a contagious superficial mite of dogs. o Intense pruritus of ears, elbows, and hocks. o Diagnose with superficial skin scrapes and pinnal-pedal reflex. o Best place to do a skin scraping in pigs is the ear canal. o Treat with Selamectin (Revolution). Use ivermectin in resistant cases. For allergies, test fleas  diet  environmental. Ctenocephalides felis is the major flea of dogs and cats. o Intermediate host for the tapeworm Dipylidium caninum. o Flea allergy dermatitis can be a type I hypersensitivity (IgE) or type IV. o Flea allergy dermatitis in dogs is pruritus of caudal third of body. o Flea allergy dermatitis in cats can be a mix of pruritus of caudal or cranial third of body. o Fleas or flea dirt may not be seen on cats because they groom and swallow them. Demodex canis is a normal resident deep inside canine skin, found in small numbers. o Demodecosis is a non-contagious skin disease. Suspected genetic component. o Localized demodicosis is in young dogs in circumscribed areas. Usually spontaneously resolves. o Generalized demodicosis can occur in young or adult dogs. More serious and needs treatment. o Diagnose with multiple deep skin scrapings and hair pluckings. o Treat generalized cases with Amitraz dips. Don’t use corticosteroids.  Can also use Ivermectin. Cheyletiella are surface mites (walking dandruff). o Diagnose with scotch tape preparation. o Treat with Selamectin (Revolution). o Cheyletiella is the fur mite of rabbits that causes scaly dermatosis and dorsal hair thinning. Malassezia pachydermatitis is a yeast that is part of the dog’s normal flora. o Malassezia causes dermatitis via a type I hypersensitivity reaction in response to other primary skin diseases. o Causes a sudden increase in baseline pruritus. o Often affects neck and interdigital areas. o Diagnose with skin cytology (should not see any yeast on normal dog skin).

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o Treat with topical Miconazole and Chlorhexadine. “Hot spots” are areas of acute moist dermatitis. o Due to self-induced trauma from underlying pruritic or painful process. o Results in surface over-colonization of Staphylococcus pseudintermedius. o Treat by clipping and cleaning, drying with aluminum acetate, topical antibiotics and steroids, and systemic prednisolone. Staphylococcus pseudintermedius is the most common cause of superficial pyodermas. o Treat with benzoyl peroxide and chlorhexidine shampoos plus 3 weeks of ampicillin or amoxicillin. o Methicillin-resistant Staphylococcus pseudintermedius has a low risk of transfer from dogs to humans. Deep pyodermas should not be treated with steroids because they can suppress the immune system. o Treat with ampicillin for 6 - 8 weeks. o German Shephards are predisposed to severe deep pyodermas that are difficult to treat. Use benzoyl peroxide shampoos for body fold pyodermas. o Moist, dark, and warm environments have overgrowth of bacteria or yeast. Food allergies are type IV hypersensitivity reactions. No antibody involvement. o Non-seasonal pruritius with possible sequelae of other dermatologic conditions. o Steroids do not always reduce pruritus. Atopic dermatitis (environmental allergies) is a type I hypersensitivity with IgE response. o Seasonal problem that progresses to non-seasonal. Causes pruritus and secondary dermatological problems. o Predisposed breeds include terriers, bulldogs, and Shar-Peis. o Treat with steroids, antihistamines, Apoquel, and allergy-specific immunotherapy (ASIT).  Omega-3 fatty acids can help by decreasing inflammation. Dermatophytosis is ringworm, a fungal disease.

o o Microsporum canis is most common cause of ringworm in cats and dogs.  Microsporum gypseum is geophilic (soil) and usually affects dogs.  Trichophyton mentagrophytes affects rodents and goats.  Microsporum nanum affects pigs and llamas.

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 Trichophyton verrucosum affects cattle. o Affects keratin and causes non-scarring alopecia. o Diagnose with Wood’s lamp, trichogram (hair shaft examination), and dermatophyte test media.  Dermatophyte test media will turn red in < 2 weeks.  The most important diagnostic is microscopic examination of macroconidia to identify genus and species. o Localized form will have spontaneous remission.  Use topical Miconazole or lyme sulfur dip & systemic Griseofulvin. Pemphigus complex is 4 autoimmune diseases associated with papulo-pustular or vesiculo-bullous lesions. o Attacks the desmosomes, which hold epidermal cells together. o Type II hypersensitivity reaction. o Photo-aggravated (not induced) disease. o Creates sterile pustules and acantholytic cells. o Most important diagnostic lesion is an intact pustule. Submit it in formalin. o Treat with prednisolone, tetracycline, and niacinamide The feline eosinophilic granuloma complex (eosinophilic ulcers, eosinophilic plaques, and linear granulomas) can occur in response to many diseases. o Eosinophilic ulcers affect oral area and will be non-painful and non-pruritic (not bother cat). o Eosinophilic plaques are raised, red, and often ulcerated lesions. They are pruritic and often have a cobblestone appearance.  Eosinophilic plaques are most often caused by flea allergy dermatitis. o Linear granulomas (eosinophilic granulomas) are typically raised, yellow-pink, and ulcerative.  Not usually pruritic. o Treat underlying cause. Symptomatic treatment includes glucocorticoids. Demodex gatoi and Demodex cati are the two demodex mites in cats. o Demodex gatoi lives superficial and is contagious. o Demodex cati lives deep and is not contagious. Psoroptes cuniculi is the rabbit ear mite. Treat with ivermectin or selamectin. o Psoroptes is a reportable ear mite of horses. o Psoroptic mange in cattle is treated with ivermectin. Chorioptes equi is a horse mite that causes pruritus on the distal limbs and ventral abdomen. o Draft horses are particularly susceptible due to their feathered hair. o More common in winter. o Diagnose with skin scraping. Otodectes cynotis is the small animal ear mite. Treated with milbemycin. Huskies are predisposed to heritable zinc responsive dermatosis.

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Scratches is chronic seborrheic dermatitis of the pastern. Generally associated with hot or muddy environments; treat by keeping horses in a clean and dry environment.  Hepatocutaneous syndrome is a necrotizing skin disorder often associated with liver diseases. o Diagnosed with skin biopsy and histology. o Clinical signs include diffuse hyperkeratosis of footpads with ulceration and fissures, peri-ocular lesions, and lesions at the tips of the ears.  Cutaneous histiocytomas occur in dogs < 3 years old. o Causes alopecia, raised nodules that often ulcerate and regress on their own. o No treatment is necessary unless the lesions persists; then remove surgically.  Psychogenic alopecia is extremely rare in cats and can only be diagnosed after ruling out all possible allergies (flea, environmental, & food).  Barbering commonly occurs with pigmented mice. Causes alopecia with no pruritus and normal skin.  In cattle, a corn is removed by surgical removal using sedation and local anesthesia.  Familial dermatomyositis is seen in Collies & Shetland Sheepdogs. Causes severe dermatitis on nose and ears. o Diagnosed with skin and muscle biopsies. o Will regress and recur.  Puppy strangles (canine juvenile cellulitis) causes generalized lymphadenopathy, fever, and pustular lesions on face. o Thought to be immune-mediated and treat with immunosuppressive doses of prednisone.  Feline acne is a common deep pyoderma of the chin in felines. Treat by cleaning with antiseptic solutions.  Discoid Lupus Erythematosus causes loss of cobblestone appearance of the nose, depigmentation of the nasal planum, and alopecia & crusting on the face. Systemic lupus erythematosus is an autoimmune disease that can affect the joints, kidneys, bone marrow, and lymph nodes. o Externally, systemic lupus erythematosus causes lesions at the mucocutaneous junctions.  Test with an anti-nuclear antibody test.  Canine pinnal alopecia is a breed-related disease most commonly seen in Dachshunds.  Epidermal collarettes are circular lesions with peelings edges. o Epidermal collarettes are remnants of previous primary lesions.  Papules are circumscribed, solid elevations of skin with no visible fluid. o Macules are flat changes in surface color. o Folliculitis is inflammation of the hair follicle.  Furunculosis is deep, swollen, and painful folliculitis. o Pyoderma is inflammation / infection of the skin.  Acanthosis nigricans causes hyperpigmentation of the axilla and groin. o Primarily occurs in Dachshunds.

Ophthalmology 

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Extraocular polymyositis causes exophthalmos without pain or swelling. o Most prominent in young Golden Retrievers. The meibomian glands produce the lipid layer of the tear film. o The conjunctival goblet cells produce the mucous layer of the tear film. o The lacrimal gland and gland of the 3rd eyelid produce the aqueous portion of the tear film.

Neurology  

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Thoracic limbs get their nerves from C6-T2 & pelvic limbs get their nerves from L4-S2. Limbs that gain nerves from the area of a spinal cord lesion will have decreased reflexes and proprioceptive deficits. o Limbs caudal to a spinal cord lesion will have normal to hyper-reflexes and proprioceptive deficits. o Limbs cranial to a spinal cord lesion will be unaffected. Dogs with fibrocartilaginous embolism usually get better on their own with nursing care. With radial nerve disease, the elbow is dropped, the digits are knuckled onto their dorsal surface, and the limb is unable to bear weight. o Commonly due to lying on the limb for long periods. An anal reflex implies function of spinal cord segments S1 – S5. Cervical spondylopathy is a malformation of the cervical vertebral canal that causes sporadic ataxia, paresis, and UMN signs in all limbs. Cushing’s reflex states that with elevated intracranial pressure, the body increases systemic blood pressure to perfuse the brain by overcoming the increased ICP. The hypertension leads to bradycardia. Cushing’s reflex causes hypertension and bradycardia. o Maintain high PaO2, low PaCO2, low cerebral metabolic rate, & normal mean arterial pressure. o Treat increased ICP with mannitol and increasing angle of head. Chlorhexadine and aminoglycosides are associated with peripheral vestibular disease. o Metronidazole is associated with central vestibular disease. Cranial nerve VII (facial nerve) damage can cause exposure keratitis because it is responsible for lacrimation.

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o Cranial nerve V (trigeminal nerve) damage can cause loss of motor function in the muscles of mastication. The mandibular branch of cranial nerve V (trigeminal nerve) provides motor innervation to the muscles of mastication. Type I disc herniation is acute. Type II disc herniation is chronic. Horner’s syndrome is due to disruption of the vagosympathetic trunk. Causes miosis, enophthalmos, ptosis, prolapsed 3rd eyelid, and sweating. o Neck masses, chest masses, chronitc otitis, retrobulbar disease, guttural pouch disease, hypothyroidism, and diabetes mellitus can result in Horner’s syndrome.  Chorioretinitis does not cause Horner’s syndrome. Unilateral facial nerve paralysis in cats is usually idiopathic. o Clinical signs are usually permanent and the opposite side of the face may become affected.

Theriogenology Dentistry

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o Enamel makes up most of the crown of the tooth and covers the dentin. o The pulp cavity contains blood vessels and nerves and is covered by dentin. o A fractured tooth exposes pulp and makes the tooth painful & suseceptible to infection. Apical means toward the tooth root. o Occlusal is towards the crown o Buccal means towards the cheek. o Lingual means towards the tongue. Hypsodont teeth are high-crowned teeth found in large animals and rodents.

o Radicular hypsodont teeth are continuously erupting, but not growing (there is a finite amount of tooth). Found in horses and cattle. o Aradicular teeth are continuously growing. Found in rodents.  Brachydont teeth are less-crowned teeth. Consist of deciduous and adult teeth. Found in dogs, cats, and humans.  Dog dental formula is 2x (3142/3143) = 42 teeth. o Cat dental formula is 2x (3131/3121) = 30 teeth. o Ruminant dental formula is 2x (0033/4033) = 32 teeth.  Ruminants do not have upper incisors or canines. o Horse dental formula is 2x (3[0-1][3-4]3/3[0-1]43) = 36 - 42 teeth. Dogs have 6 teeth that are 3-rooted (P4, M1, M2). All are in the maxilla o The carnassial tooth in the dog is the upper 4th premolar.  A probe is used to measure gingival pocket depth and tooth mobility. o An elevator breaks down the periodontal ligament. o A scaler removes supragingival calculus. o A polisher removes plaque and smooths teeth after a scaler is used. o Extraction forceps are used to remove a tooth after the periodontal ligament is broken down.  The most common canine oral malignancy is a melanoma. o The most common feline oral malignancy is a squamous cell carcinoma. o The most common gingival mass in dogs is focal fibrous hyperplasia.  Endodontics is any treatment involving the pulp cavity, such as a root canal. o A root canal removes infected pulp cavity and fills it.  The best antibiotics for dental infections are clindamycin & clavamox because they kill anaerobic bacteria. o If there are dental infections, start on antibiotics a few days before the dental cleaning. o Animals that have extractions should stay on antibiotics for 2 weeks after extractions.  A short-term treatment for periodontal disease is daily chlorhexidine rinses.  Feline Odontoclastic Resorption Lesions (FORL) are most often found on the first premolars (307 & 407) and are very painful. o These are resorbing teeth that need to be extracted. Internally and externally affected. (Extract entire tooth.)  Do not combine oral surgeries with systemic surgeries because oral surgeries cause significant bacteremia, which can cause wound infection.  Horse teeth must be floated on the lingual side of the mandible and the buccal side of the maxilla. o The horse mandible is narrower than the maxilla.  Horses commonly get malocclusions, rostral hooks, caudal hooks, and retained deciduous teeth.

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o Caries (tooth decay due to bacteria) are due to decalcification of the teeth and are rare. Dentigerous cysts in horses are due to having tooth tissue in the ear. o Causes a mucopurulent discharge around the ear. o Treat with surgical removal. Most cases of canine oral papillomatosis resolve without treatment in 3 months. The oldest tooth in the horse is premolar 1 (the wolf tooth). Erupts at 6 months old. o Incisors erupt at 2.5, 3.5, & 4.5 years-old. o Canine teeth in horses erupt at 4 years old. o Galvayne’s groove begins at 9 years-old. In cows, the permanent incisors are present at 1.5, 2.5, 3.5, and 4.5 years-old (from first to fourth incisor).

Orthopedics

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o Primary bone tumors usually occur at the metaphysis whereas metastatic bone tumors usually occur at the diaphysis Osteosarcoma is the most common primary bone tumor. o Occurs away from the elbow and towards the knee. o Amputation is curative in cats but has less than a 1 year-survival time in dogs. Valgus is a lateral deformity of the limb; varus is a medial deformity. o Diagnose angular limb deformities with carpal and tarsal radiographs. The treatment for hip dysplasia that gives the best return to function is a total hip replacement. o A bunny-hopping goat is commonly seen. o Will see a positive Ortolani sign (femoral subluxation in hip joint).

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The treatment for severe carpal hyper-extension injuries is carpal arthrodesis (joint fusion). Most coxofemoral luxations are craniodorsal. Routes of infection to joints include foreign body, hematogenous spread, and extension of cellulitis. o Lymphatic spread is not a rout of joint infection. Long-term sling application can cause muscle contracture, muscle disuse atrophy, and joint fibrosis. The 3 goals of articular fracture repair are complete anatomic realignment, rigid fixation of fracture fragments, & early return to function. o Goals of long bone fracture repair are extended rest and at least 50% anatomic alignment. Feed large breed puppies a low-calcium diet to prevent skeletal abnormalities. Small breed dogs have a poor blood supply to the distal radius and ulna and are less likely to heal with a cast. Rabbit fractures do not heal well with splints. In an adult horse, tibia fractures carry a grave prognosis. o P1, P3, & ulna fractures can be repaired well. Foal carpal bones should be fully ossified at time of birth. Incompletely ossified carpal bones indicates a premature foal. Intramedullary pins are strong against bending but do not provide good stability by themselves. o Use in conjunction with bone plates. Femoral fractures in calves are easily treated with intramedullary pins. Salter-Harris fractures: o

Type I fractures are through the physis. Type II fractures are through the metaphysis & physis. Type III fractures are through the physis & epiphysis. Type IV fractures are through the metaphysis, physis, & epiphysis. Type V fractures are crush injuries to the physis.  Type V Salter-Harris fractures can lead to angular limb deformities. Hypertrophic osteopathy causes a periosteal proliferation of the diaphysis due to pulmonary neoplasia. o Usually affects metacarpal and metatarsal bones before advancing to long bones. o Joints are unaffected. o o o o o

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Hypertrophic osteodystrophy causes destroyed bone in distal metaphyses of forelimbs before spreading proximally. o Occurs in young, large breed animals. o Can be extremely painful and cause lameness. o Treat with analgesics and supportive care. o Episodes can recur. o Angular limb deformity is a possible complication. o Will appear on radiographs as a line of lucency (destroyed bone) parallel to the growth plate. o Weimaraners are predisposed and may be due to recent vaccination. Craniomandibular osteopathy is seen in young dogs, usually terriers. o Though to be a form of hypertrophic osteodystrophy. o Very painful. o Self-limiting and regresses by 1 year-old. o Treat supportively

o Panosteitis is long bone inflammation usually seen in young, rapidly growing, large breed dogs. o Radiographs show focal intramedullary densities. o Self-limiting, painful condition that causes limping and lameness. o Treat with carprofen and limiting activity. Luxating patellas in dogs are usually to the medial side. o Most common in small breed dogs. o Surgical repair involves medial release of soft tissues, block recession of trochlear groove, lateral transposition of the tibial tuberosity, and lateral imbrication of the retinaculum. Osteochondritis dissecans (OCD) occurs in young large breed dogs and is painful. o Causes endochondral ossification of the epiphyseal cartilage. o OCD of the shoulder is the most common location is commonly bilateral. o Treat by surgically removing cartilage flaps and giving NSAIDs. o Osteochondritis is least common in cattle. Feline mandibular symphysis separation commonly occurs when cats fall from heights. o Treat with circummandibular cerclage wire placed caudal to the canine teeth. o Remove cerclage wire after 6 weeks. o Not a true fracture because the mandibular symphysis never closes. Immune-mediated polyarthritis (IMPA) is usually non-erosive. o Normally idiopathic.

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o Causes fever, lethargy, lymphadenopathy, and joint effusion. o Treat with immunosuppressive drugs (prednisone, azathioprine, or cyclophosphamide). Cranial cruciate ligament rupture is diagnosed with tibial thrust and cranial drawer. o The medial meniscus is usually damaged as well. o Repair with a tibial plateau leveling osteotomy (TPLO) will still have a cranial drawer. o Radiographs show joint effusion and mild degenerative bone changes. Spondylosis is degenerative intervertebral joint space disease. Avascular necrosis of the femoral head results in collapse or fragmentation of the femoral epiphysis. o Occurs in young small breed dogs. o Treat with femoral head and neck ostectomy. Degenerative joint disease is treated with omega-3 fatty acids, weight loss, and controlled leash walks. o Save carprofen for later. o Omega-3 fatty acids decrease production of inflammatory eicosanoids. The most common issue seen with elbow dysplasia is a fragmented medial coronoid process of the ulna.

Anesthesia / Drugs  

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With younger patients, you must be concerned about hypoglycemia and hypotension. Until oxygen pressures reach < 60mmHg, there is little change in oxygen saturation. o Oxygen pressure of 60 mmHg means there is 90% oxygen saturation. Below 60 mmHg, oxygen saturation declines rapidly. Adrenergic receptors are stimulated by epinephrine and norepinephrine. o Alpha-1 & Alpha-2 adrenergic receptors are sympathetic receptors located on the arteries. They increase blood pressure by constricting arteries, which causes bradycardia. o Beta-1 adrenergic receptors are in the heart and increase heart rate & contractility. o Beta-2 adrenergic receptors are in the lungs and smooth muscle. They dilate bronchioles (let more air in lungs) and dilate skeletal muscles (to get more muscle blood flow). Blood pressure is the force of the blood pushing against the arteries. o Vasodilators decrease blood pressure.  Vasoconstrictors increase blood pressure. o Hypotension is systolic pressure less than 80mmHg & mean pressure less than 60 mmHg.  Treat hypotension by decreasing anesthetic gas, fluid boluses, and atropine / glycopyrrolate.

Can use dopamine (an alpha agonist) or norepinephrine CRIs to raise blood pressure. Normal end-tidal CO2 is 35 – 40 cmH20. o Best way to decrease CO2 is to increase ventilation. Can manually do this or decrease anesthetic gas. Cardiopulmonary arrest: o Under anesthesia, you have ~50% chance of return of spontaneous circulation (complete survival rate).  Under other circumstances, you have ~5% chance. o The purpose of chest compressions and giving breaths is to maintain blood flow until you can get epinephrine into the body.  Chest compressions by themselves are unlikely to return spontaneous circulation. o Signs of cardiopulmonary arrest include:  Lack of cardiac activity (no heart rate or blood pressure)  Apnea (lack of breathing)  Centrally fixed eye with mydriasis o What to do with cardiopulmonary arrest:  Turn off anesthetic gas and any other depressants (opioid CRIs, etc.)  Give shock dose bolus of fluids.  Ensure that airway is maintained by endotracheal tube (palpate larynx or use laryngoscopre).  Give 10 breaths per minute.  Give cardiac compressions (120 compressions per minute). Purpose of external cardiac massage is to deliver oxygen and epinephrine to the heart and periphery.  Give 1 – 2 doses of low dose of epinephrine (0.01 mg/kg).  Give a high dose of epinephrine (0.1 mg/kg) after that.  Epinephrine has alpha and beta adrenergic effects. It directly increases heart rate, heart contractility, and blood pressure. It decreases total peripheral resistance.  Can give atropine if you suspect the arrest is due to vagal stimulation.  Open the chest at 4th intercostal space after five minutes of unsuccessful compressions for intra-thoracic cardiac compressions.  Compress apex to base (reverse milking). All anesthetic drugs diminish thermoregulation. o Never use electric blankets because they burn animals. o Cold temperature decreases coagulation, decrease leukocyte function, and causes peripheral vasoconstriction (hyperperfusion). o Low temperatures lower the MAC of anesthetic gases, thus decreasing the required amount of gas. o Hypothermia is protective against ischemic damage. 

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Small, young, cachectic patients are at risk for hypoglycemia during surgery. o Can cause sympathetic hyperactivity. Guaifenesin is a centrally-acting muscle relaxant with an unknown mechanism. o Succinylcholine is a depolarizing neuromuscular blocking agent. o Atracurium is a non-depolarizing neuromuscular blocking agent. Premedication: o Premedication is administration of drugs prior to anesthetic induction. o Reduces apprehension, facilitates handling, enhancing peri-operative analgesia, and minimizing adverse effects of anesthetic drugs. o Acepromazine  This is a phenothiazine.  Tranquilizer that is a dopamine antagonist.  Commonly given with an opioid for neuroleptanalgesia (a state of minimal responsiveness).  Major side effect is hypotension by being an alpha-1 antagonist. This is offset by benefits in healthy animals, but don’t use in hypovolemic patients.  Also decreases seizure threshold and platelet function. o Only decreases seizure threshold IV at higher doses.  Causes splenic dilation, decreased hemoglobin concentration, and decreased hematocrit. o Don’t use acepromazine with splenic masses.  This can be reversed with the alpha-agonist phenylephrine, which has no cardiac effects.  Not reversible and not an analgesic.  Protects from arrhythmias, is an antiemetic, causes penile protrusion in horses, & is an antihistamine.  Decreases anesthetic requirements up to 40% (lowers MAC) o Opioids can be used as premedications. o Alpha-2 agonists: (Xylazine, Medetomidine, & Dexmedetomidine)  Ruminants are more susceptible.  Analgesics, sedatives, and muscle relaxants  Reversed by yohimbine & atipamezole.  Can cause bradycardia, AV block, and decrease GI motility. Causes hypertension then hypotension.  Don’t use in pregnant females because it increases uterine tone.  Inhibit insulin and cause hyperglycemia.  Inhibits anti-diuretic hormone (ADH), which means they increase diuresis  Xylazine can be given to cats to vomit.  Avoid in critically ill and heart failure patients because of cardiovascular effects.

o Benzodiazepines: (Diazepam, Midazolam, & Zolazepam)  Muscle relaxants and anxiolytics  Are not analgesics  Reverse with Flumazenil o Anticholinergics: (Glycopyrrolate & Atropine)  Inhibit parasympathetic innervation; they increase heart rate and cause bronchodilation  Decrease GI motility, salivation, and bronchial secretions  Cause mydriasis  Opioids: o Analgesics that are parasympathomimetics (activate parasympathetic system).  Major side effects dysphoria, respiratory depression, sedation, vomiting, constipation, and bradycardia.  Decrease the anesthetic requirement (decrease MAC) of isoflurane.  Subcutaneous administration causes more vomiting than other administrations.  When combined with acepromazine emesis is inhibited. o Mu-agonists have greater analgesia than kappa-agonists. o Reversed with Naloxone. o Hydromorphone  Pure agonist o Methadone  Pure agonist o Buprenorphine  Mixed agonist-antagonits o Fentanyl  Pure agonist  Shortest half-life; normally given as a CRI o Butorphanol  Mixed agonist-antagonists o Morphine  Pure agonist  Induces histamine release, so don’t use with mast cell tumor patients.  Epidural morphine provides analgesia for at least 12 hours. o Tramodol  Longest acting opoid Induction Agents: o Propofol:  An induction anesthetic unrelated to other general anesthetics.  Causes poor analgesia.  Mechanism of action is unknown.  Causes respiratory depression, increased intraocular pressure, and bradycardia.

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With repeated doses, propofol can cause Heinz body anemia in cats.  Short duration of action (2 – 5 minutes)  Cleared by the liver.  Cats usually recover from propofol rapidly and smoothly.  Not a controlled substance.  No antagonist. Alfaxalone:  Neuroactive steroid molecule that binds to GABA receptors (inhibitory neurotransmitter).  Can cause respiratory depression, but to a lesser degree than propofol.  Provides poor analgesia. Benzodiazepines Ketamine  Ketamine causes an increase in muscle tone, increased intraocular pressure, and increased sympathetic tone. Causes tachycardia and should be avoided in cats. That’s because up to 20% of cats have undiagnosed hypertrophic cardiomyopathy, where you want to lower heart rate to improve diastolic filling.  Preserves blood pressure and breathing well. Also provides some analgesia. Combined with diazepam, ketamine is a very good induction agent in healthy patients.  Don’t use in head trauma patients because it will increase intracranial pressure. Also don’t use in hyperthyroid patients because it can cause thyroid levels to increase. Don’t use with pheochromocytomas or heart disease because ketamine causes an increase in catecholamines.  Cleared by kidneys in cats and liver in dogs. Thiopental is a barbiturate that can cause cardiac arrhythmias.  Thiopental is the barbiturate with the shortest onset of action and duration.  Ventricular bigeminy is the most common arrhythmia.  Thiopental, like acepromazine, causes splenic engorgement.  Is a strong irritant if it goes perivascular. Treat by diluting the area with saline.  Not gold standard but can be used effectively and cheaply in healthy patients.  Don’t use in sighthounds (including Greyhounds) because they don’t metabolize it well.  Protein-bound, so will get a disproportionately large effect in hyperproteinemic animals.

Inhalant Anesthetics: o Advantages over injectable anesthetics are minimal metabolism, rapid adjustment, and the ability to give with oxygen. o Inhalant anesthetics are the most cardiodepressive drugs. o Inhalant anesthetics are vasodilators, which decrease blood pressure. o Can cause malignant hyperthermia due to a hypermetabolic state, especially in swine.  Treat with Dantrolene. o Less potent & higher MAC = slower induction and recovery. o Lower mean alveolar concentration (MAC) means increased potency.  Desflurane has the highest MAC & Isoflurane has the lowest MAC. o Sevoflurane  Smoother induction.  Medium potency (less than isoflurane & more than desoflurane)  Produces breakdown product called Compound A which may cause renal damage. o Desflurane  Least potent o Isoflurane  Most potent o Halothane  Highly metabolized by the liver  Makes myocardium more susceptible to catecholamine-induced arrhythmias.  Can cause malignant hyperthermia. o Nitrous Oxide  Cannot be used by itself for clinical anesthesia because of its high MAC. Azathioprine is an immune-suppressive drug not normally used in cats because of bone marrow suppression. Prednisone should not be used with infection because it will suppress the immune system. o Cats and horses get prednisolone. o Steroids also have anti-insulin effects (can cause diabetes), joint problems, skin disorders, and renal disorders. Cyclophosphamide is an immune-suppressive drug.  Ketoconazole can cause hepatotoxicity, anorexia, vomiting, diarrhea, and adrenal insufficiency. Ivermectin stimulates GABA, an inhibitory neurotransmitter. o Ivermectin is active against mites, nematodes, and ticks.  Not active against trematodes (flukes). Praziquantel only treats tapeworms.  Penicillins (Penicillin, Ampicillin, Amoxacillin) work by inhibiting formation of peptidoglycan cross-links in bacterial cell walls.

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o Effective against gram + and anaerobic bacteria. o Can combine with beta-lactamase inhibitors such as clavulanic acid to extend spectrum of activity. o NEVER give procaine penicillin intravenously; it causes CNS toxicity. Cephalosporins (Cephalexin, Cefazolin, Ceftiofur) work by inhibiting formation of peptidoglycan cross-links in bacterial cell walls. o Later generations effective against gram +, gram -, & anaerobic bacteria. Vancomycin works by interfering with cell wall synthesis. o Effective against gram + bacteria. o Use against resistant bacteria only. Aminoglycosides (Gentamycin, Neomycin, Amikacin) work by binding to the 30s ribosomal subunit, which interferes with protein synthesis. o Effective against gram - bacteria. o Nephrotoxic & ototoxic o Poorly absorbed by feline intestinal tract. Tetracyclines (Tetracycline and Doxycycline) work by binding to the 30s ribosomal subunit, which interferes with protein synthesis. o Effective against gram +, gram -, & anaerobic bacteria. Also effective against Ehrlichial, Anaplasmal, and Rickettsial bacteria. o Nephrotoxic and will discolor teeth in puppies. Chloramphenicol works by binding to the 50s ribosomal subunit, which interferes with protein synthesis. o Effective against gram -, gram +, & anaerobic bacteria. o Causes bone marrow depression in humans. o Forbidden in food animals. Lincosamides (Lincomycin, Clindamycin) work by binding to the 50s ribosomal subunit, which interferes with protein synthesis. o Effective against gram + & anerobic bacteria. o Do not use in horses. Macrolides (Erythromycin, Azithromycin, Clarithromycin) work by binding to the 50s ribosomal subunit, which interferes with protein synthesis. o Effective against gram + & anaerobic bacteria. Metronidazole works be breaking apart DNA. o Effective against anaerobic bacteria & protozoa. o Can have neurologic side effects. Rifampin works by inhibiting RNA polymerase. o Effective against gram + bacteria. o Mainly used against Rhodococcus equi in foals. Fluoroquinolones (Enrofloxacin, Ciprofloxacin) work by inhibiting DNA gyrase. o Effective against gram - bacteria. o Can damage cartilage in young animals.

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Trimethoprim-sulfamethoxazole (also known as TMS) works by interfering with folate metabolism. o Effective against gram +, gram -, & anaerobic bacteria.

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On bacterial culture & sensitivity reports, oxacillin indicates methicillin resistance. Streptococcus & Staphylococcus are gram + cocci. Clostridium are anaerobes. Nocardia & Actinomyces are gram-positive filamentous rods. o Actinomyces is a normal flora of the mouth and orpharynx. Klebsiella is a gram-negative encapsulated facultative anaerobic rod. Mycobacteria, Nocardia, and some coccidian parasites are acid fast.