MedStudy’s 2014 Pediatrics Board-Style Questions & Answers Editor in Chief Robert A. Hannaman, MD MedStudy Colorado Springs, CO Author Paul Catalana, MD, MPH, FAAP Assistant Dean of Admissions Clinical Associate Professor of Pediatrics University of South Carolina School of Medicine Greenville Greenville, SC Note: Paul Catalana, MD, MPH, FAAP has documented that he has no relationships with entities producing, marketing, re-selling, or distributing health care goods or services consumed by, or used on, patients. MedStudy Disclosure Policy It is the policy of MedStudy to ensure balance, independence, objectivity, and scientific rigor in all of its educational activities. In keeping with all policies of MedStudy and the Accreditation Council for Continuing Medical Education (ACCME), specifically ACCME’s Standards for Commercial Support, any contributor to a MedStudy CME activity is required to disclose all relevant relationships with any entity producing, marketing, re-selling, or distributing health care goods or services consumed by, or used on, patients. Failure to do so precludes acceptance by MedStudy of any material by that individual. All contributors are also required to submit a signed Good Practices Agreement affirming that their contribution is based upon currently available, scientifically rigorous data; that it is free from commercial bias; and that any clinical practice and patient care recommendations offered are based on the best available evidence for these specialties and subspecialties. All content is carefully reviewed by MedStudy’s CME Physicians Oversight Council, as well as on-staff proofreaders, and any perceived issues or conflicts are resolved prior to publication of an enduring product or the start of a live activity. MedStudy Disclosure
MedStudy Corporation, including all of its employees, has no financial interest, arrangement or affiliation with any commercial entity producing, marketing, re-selling, or distributing health care goods or services consumed by, or used on, patients. Furthermore, MedStudy complies with the AMA Council on Ethical and Judicial Affairs (CEJA) opinions that address the ethical obligations that underpin physician participation in CME: 8.061, “Gifts to physicians from industry,” and 9.011, “Ethical issues in CME,” and 9.0115, “Financial Relationships with Industry in CME.” For Further Study MedStudy Pediatrics Board Review Core Curriculum, 6th Edition. MedStudy Corporation, Colorado Springs, CO, 2014. MedStudy Pediatrics Flash Cards, 2014–2015 Edition, MedStudy Corporation, Colorado Springs, CO, 2014. Nelson Textbook of Pediatrics, 19th Edition. Robert M. Kliegman, Bonita M.D. Stanton, Joseph St. Gerne, Nina Schor, and Richard E. Behrman. W.B. Saunders. Elsevier Science Health Science Division, New York, NY, 2011. Rudolph’s Pediatrics, 22nd Edition. Colin D. Rudolph, Abraham M. Rudolph, George Lister, Lewis R. First, and Anne A. Gerson (eds). McGraw Hill Medical, New York, NY, 2011. Oski’s Pediatrics: Principles and Practice, 4th Edition. Julia McMillan, Ralph D. Feigin, Catherine D. DeAngelis, and M. Douglas Jones (eds). Lippincott Williams & Wilkins, Philadelphia, PA, 2006. Smith’s Recognizable Patterns of Human Malformation, 7th Edition. Kenneth Jones. W.B. Saunders. Elsevier Science Health Science Division, New York, NY, 2013. Atlas of Pediatric Physical Diagnosis, 6th Edition. Basil J. Zitelli and Holly W. Davis. Mosby/Elsevier Science Health Science Division, New York, NY, 2012. Bright Futures: Guidelines for Health Supervision of Infants, Children, and Adolescents, 3rd Edition. Joseph F. Hagan, Jr., Judith S. Shaw, and Paula M. Duncan (eds). American Academy of Pediatrics, Philadelphia, PA, 2008.
Web-based: National Guideline Clearinghouse: http://www.guideline.gov/ AAP Clinical Practice Guidelines: http://www.aap.org/en-us/professional-resources/practice-support/ quality-improvement/Pages/Clinical-Practice-Guidelines.aspx AAP-Endorsed Clinical Practice Guidelines: http://pediatrics.aappublications.org/search?flag=endorsed_practice_guidelines&submit=yes&x=18&y=8&format=standard&hit s=30&sortspec=date&submit=Go AAP Clinical Reports: http://pediatrics.aappublications.org/search?fulltext=clinical+reports&submit=yes&x=44&y=10
MedStudy
®
2014 2 0 0 9
Pediatrics
Board-Style
Questions
&
Answers
QUESTIONS
Edited by Robert A. Hannaman, MD
MedStudy
TABLE OF CONTENTS ADOLESCENCE.............................................................. ALLERGY / IMMUNOLOGY / RHEUMATOLOGY .... CARDIOLOGY ................................................................ DERMATOLOGY............................................................ EMERGENCY MEDICINE ............................................. ENDOCRINOLOGY ........................................................ ENT / OPHTHALMOLOGY / ORTHOPEDICS ............. GASTROENTEROLOGY ................................................ GENETICS / METABOLIC DISEASES ......................... GROWTH and DEVELOPMENT. ................................... HEALTH SUPERVISION................................................ HEMATOLOGY / ONCOLOGY ..................................... INFECTIOUS DISEASES................................................ NEPHROLOGY ............................................................... NERVOUS SYSTEM / NEUROLOGY ........................... NEWBORN / PRENATAL CARE ................................... NUTRITION / TEETH ..................................................... RESPIRATORY ............................................................... APPENDIX A – Reference color photos APPENDIX B – Antibiotics Tab
5 21 33 41 59 71 79 85 95 111 119 131 143 165 171 179 195 203
Important: These Q&A books are meant to be used as an adjunct to the MedStudy Pediatrics Review Core Curriculum. The Pediatric Boards cover a vast realm of diagnostic and treatment knowledge. Board-simulation exercises such as these self-testing Q&As are valuable tools, but these alone are not adequate preparation for a Board exam. Be sure you use a comprehensive Pediatrics review resource in addition to these Q&As for adequate exam preparation.
Content: The primary purpose of this activity is educational. Medicine and accepted standards of care are constantly changing. We at MedStudy do our best to review and include in this activity accurate discussions of the standards of care, methods of diagnosis, and selection of treatments. However, the author, editors, advisers, and publisher—and all other parties involved with the preparation of this work—disclaim any guarantee that the information contained in this activity and its associated materials is in every respect accurate or complete. MedStudy further disclaims any and all liability for damages and claims that may result from the use of information or viewpoints presented. We recommend you confirm the information contained in this activity and in any other educational material with current sources of medical knowledge whenever considering actual clinical presentations or treating patients. A note on editorial style: MedStudy follows a standardized approach to the naming of diseases, using the non-possessive form when the proper name of a disease is followed by a common noun. So you will see phrasing such as “This patient would warrant workup for Crohn disease” (as opposed to “Crohn’s disease”). Possessive form will be used, however, when an entity is referred to solely by its proper name without a following common noun. An example of this would be “The symptoms are classic for Crohn’s.” Styles used in today’s literature can be highly arbitrary, some using possessive and some not, but we believe consistency is important. It has become nearly obsolete to use the possessive form in terminology such as Lou Gehrig’s disease, Klinefelter’s syndrome, and others. The AMA Manual of Style, JAMA, Scientific Style and Format, and Pediatrics magazine are among the publications that are now promoting and using the non-possessive form. We concur with this preference. © 2014 by MedStudy Corporation. All rights reserved by MedStudy Corporation WARNING: THE UNAUTHORIZED REPRODUCTION OR DISTRIBUTION OF THIS COPYRIGHTED WORK IS ILLEGAL. CRIMINAL COPYRIGHT INFRINGEMENT, INCLUDING INFRINGEMENT WITHOUT MONETARY GAIN, IS INVESTIGATED BY THE FBI AND IS PUNISHABLE BY UP TO 5 YEARS IN FEDERAL PRISON AND A FINE OF $250,000. ANY PERSON MAKING, SELLING, OR PURCHASING UNAUTHORIZED COPIES OF THIS MATERIAL WILL BE SUBJECT TO LEGAL ACTION AND SEVERE PENALTIES UNDER U.S. COPYRIGHT LAW, AND MAY FACE CRIMINAL CHARGES. Notifications of copyright infringement should be sent in confidence to MedStudy Corporation, 1455 Quail Lake Loop, Colorado Springs, Colorado 80906 Or e-mail to:
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2014 Pediatrics Board-Style Questions
About the questions and answers in this learning activity The questions, answers, and explanations in this learning activity are developed by the author, Paul V. Catalana, MD, MPH, FAAP. Dr. Catalana has a background of more than 20 years in professional medical education. He is also a reviewer/section editor for the MedStudy Pediatrics Review Core Curriculum and a teacher at the MedStudy live Pediatrics Intensive Board Review Course. Dr. Catalana is a Clinical Associate Professor of Pediatrics at the University of South Carolina School of Medicine in Greenville, South Carolina. He is Board Certified in both pediatrics and adolescent medicine and is a member of the American Academy of Pediatrics. Knowing the importance that the Peds Boards place on established standards of care, having researched recent and pertinent practice guidelines, and having reviewed the ABP Board exam blueprints, Dr. Catalana is well aware of the areas of knowledge most likely to be tested on today’s Board exams. The questions emphasize test areas that are difficult to learn as well as provide classic vignettes to help you remember more common diseases. You will find questions of varying length here. The very short ones are designed to nail home an important point you need to know and remember for your Boards. The lengthier questions help you integrate content on a subject with additional clinical information to better simulate a real-life patient scenario. This helps you recognize disease states and associated treatment, which is a skill heavily tested on Board exams. Some selected patient case scenarios may appear more than once, or with only slight variations, with the associated questions addressing different diagnosis and treatment aspects of the case. This is in keeping with the approach Board questions take in limiting patient case assessments to one key testing point. In short, this Q&A material is designed to impart not only relevant knowledge for Peds Board exams but also challenge your skills in interpretation and intervention, which is what Board exams attempt to assess. Which is why we call these, appropriately, “Board-style” questions and answers. There is a popular misconception that members of organizations perceived to be associated with medical boards write Board exam questions, such as AAP/PREP with the American Board of Pediatrics. Not only is this not true, it is actually forbidden for anyone to write formal Board exam questions if they work for a company or organization in the business of producing Board preparation materials. This would compromise the integrity of the examining process. MedStudy is proud to be able to bring you Board-style questions and answers of the highest quality—to offer you education that is relevant in a format that reinforces your knowledge to prepare you well for whatever challenge the ABP Board exam presents you. One final note: Even the best question-and-answer exercise by itself is not an adequate preparation for a Board exam. These Q&As should be used as an adjunct to a comprehensive Board review course (such as the MedStudy Pediatrics Review Core Curriculum). The Boards cover a vast realm of information that Board-simulation Q&As alone cannot encompass. Robert A. Hannaman Editor in Chief MedStudy
2014 Pediatrics Board-Style Questions
CARDIOLOGY 72. While working as a landscaper during summer vacation, a 16-year-old male, according to his boss, suddenly “fainted just after complaining of being nauseated and dizzy.” He reportedly “came around quickly” after his legs were elevated and a cold rag was applied to his forehead. No associated tonic-clonic activity was observed. On physical examination, his blood pressure is 110/75; pulse is 64 beats/minute and regular. No murmurs are noted on cardiac auscultation. The patient reports that he “fell out” on 3 previous occasions within the last several months. Following additional evaluation, the patient is prescribed fludrocortisone. Which of the following was most likely abnormal during the further assessment of this patient? A. Echocardiogram B. Tilt table test C. Adrenal ultrasound D. Cranial MRI E. Nuclear stress test ___________________________________________________________________________________________
73. A 15-year-old girl presents for a pre-participation sports physical. She has no complaints, is on no chronic medications, and runs an average of 50 miles/week. On physical exam, her blood pressure is 100/65 with a resting pulse of 56 beats/minute. An echocardiogram is performed after a murmur is heard on cardiac auscultation, which reveals an ostium secundum defect in the area of the fossa ovalis. Which of the following best describes expected cardiac findings during physical examination of this patient? A. A systolic ejection murmur, best heard at the mid-to-upper left sternal border associated with a loud first and widely fixed, split-second heart sound B. A systolic ejection murmur, best heard at the mid-to-upper left sternal border associated with a diminished single-second heart sound C. A continuous murmur throughout systole and diastole associated with bounding peripheral pulses D. A rumbling mid-diastolic murmur, best heard at the upper left sternal border, associated with a loud first and widely fixed, split-second heart sound E. A harsh holosystolic murmur associated with a loud first heart sound and a paradoxically split-second heart sound ___________________________________________________________________________________________
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74. During review of an electrocardiogram obtained on a 17-year-old patient, a PR interval of 0.1 seconds is noted in association with a slow upstroke of the QRS complex. The QRS complex is also widened. Which of the following best describes the most likely clinical presentation of this patient? A. Intermittent episodes of supraventricular tachycardia B. Bradycardia associated with complete heart block C. Cardiomegaly associated with congestive heart failure D. Frequent episodes of syncope or near syncope following changes in position E. Chest pain associated with a pericardial friction rub ___________________________________________________________________________________________
75. A 4-year-old girl presents to the emergency room with a 24-hour history of cough, chest pain, and decreased exercise tolerance. On physical examination, she is alert but lethargic. Temperature is 100.2° F; blood pressure 90/65; heart rate 115 beats/minute; respiratory rate 32 breaths/minute associated with accessory muscle use and grunting. Her heart is enlarged on chest x-ray. Of note, she was recently discharged from the hospital after undergoing open atrial septal defect repair 3 weeks earlier. Which of the following is most likely to be identified during additional evaluation of this patient? A. Muffled heart sounds on auscultation B. Painful violaceous nodules in the pulp of the fingers and toes C. Absence of breath sounds over one lung field associated with a shift in the point of maximal impulse (PMI) over the cardiac apex D. A continuous murmur heard best over the left upper sternal border E. Excessive drooling and inspiratory stridor ___________________________________________________________________________________________
76. A 6-week-old girl with a rash is noted to have a heart rate of 52 beats/minute. On 12-lead ECG, the P–P and R–R intervals are regular, the PR interval is variable, and there is no apparent relationship between the P waves and the QRS complexes. Which of the following best describes the likely rash in this patient? A. B. C. D.
Sharply demarcated annular scaling plaques on the cheeks and periocular areas Reticulate bluish mottling of the lower extremities Indurated, well-circumscribed nodular erythematous plaques on the shoulders and back Blotchy erythematous macules and edematous, yellowish papules and pustules on the face, trunk, and extremities E. Papules and papulopustules associated with fine, white scales and hyperpigmented macules in areas where previous lesions have ruptured; located primarily on the inferior chin, neck, and forehead ___________________________________________________________________________________________
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2014 Pediatrics Board-Style Questions
77. During a pre-participation sports physical, a 15-year-old girl is noted to have a mid-systolic click associated with a 1/6 mid-systolic murmur. Her peripheral pulses are normal, and her examination is otherwise unremarkable. Which of the following best describes an additional feature of the disorder described in this patient? A. B. C. D. E.
The murmur and click are best heard over the right second intercostal space. Standing moves the click closer to the second heart sound. Maneuvers that increase left ventricular volume enhance ausculatory findings. These auscultatory findings occur with greater frequency among individuals with a 45,XO karyotype. These auscultatory findings represent the most common cardiac complication among patients with acute rheumatic fever. ___________________________________________________________________________________________
78. A 7-year-old boy with a history of recurrent otitis media and sinusitis is found to have normal serum immunoglobulin levels with the exception of a serum IgA concentration of < 7 mg/dL. This patient is at increased risk of adverse side effects associated with the routinely recommended treatment of which of the following disorders? A. Type I diabetes B. Kawasaki disease C. Absence (petit mal) seizure disorder D. Atopic dermatitis E. Cystic fibrosis ___________________________________________________________________________________________
79. A febrile 8-year-old boy with a 3-day history of warm tender swelling of both knees and the right ankle is noted to be tachycardic. The measured PR interval on ECG is 0.26 seconds. On cardiac auscultation, a new murmur, characterized by a high-pitched apical holosystolic murmur radiating to the axilla, is noted. Just prior to an echocardiogram, a rash is observed. Which of the following best describes the most likely appearance of this patient’s rash? A. Erythematous, serpiginous macular lesions with pale centers on the trunk and extremities B. Diffusely distributed, round erythematous swollen plaques, target lesions, and marginated wheals with central vesicles C. Diffuse erythema with small punctate papules accentuated in the flexural areas D. Erythematous macules and petechiae prominent around the ankles, wrists, palms, and soles E. Deep-seated and more superficial vesicles with peripheral erythema on the palms and plantar surfaces ___________________________________________________________________________________________
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80. A 4-year-old girl, hospitalized 6 weeks earlier with Kawasaki disease, continues recommended treatment to reduce the risk of coronary artery aneurysm. This patient should be considered at increased risk for which of the following complications if she were to become infected with an influenzae virus? A. Toxic epidermal necrolysis B. Autoimmune hepatitis C. Reye syndrome D. Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome E. Pseudotumor cerebri ___________________________________________________________________________________________
81. A 3-year-old boy is hospitalized and treated for Kawasaki disease after presenting with a history of increased temperature, extreme irritability, morbilliform rash, and mucous membrane changes. Which of the following complications is associated with the greatest risk of morbidity in patients with this disorder? A. Coronary artery dilation of ≥ 8 mm B. Administration of intravenous immune globulin ≥ 5 days after onset of symptoms C. Administration of corticosteroids ≥ 7 days after onset of symptoms D. Heart rate ≥ 120 beats/minute on presentation E. Mitral regurgitation on echocardiogram ___________________________________________________________________________________________
82. A 4-month-old girl returns for follow-up several days after being diagnosed with “bronchiolitis” at a local emergency department. Stridor is noted on physical examination. An AP chest x-ray reveals a wide heart base and, on lateral film, a narrowed trachea displaced forward at C3–C4. Which of the following is the most likely cause of this patient’s clinical and radiographic findings? A. A double aortic arch B. Pulmonary sling C. Aberrant right subclavian artery D. Anomalous origin of the left coronary artery E. Pulmonary arteriovenous fistula ___________________________________________________________________________________________
83. An ECG in a 17-year-old male with multisystem failure following a near drowning is noted to have a QTc interval of 0.36 seconds and an abrupt upslope of the T wave.
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2014 Pediatrics Board-Style Questions Which of the following is the most likely cause of this patient’s ECG findings? A. Hypokalemia B. Hypercalcemia C. Hyperkalemia D. Hypocalcemia E. Hypothermia ___________________________________________________________________________________________
84. When reviewing an electrocardiogram, which of the following components represents the time it takes for the cardiac impulse to travel through the atrioventricular (AV) node? A. The P wave B. The ST segment C. The PR interval D. The QT segment E. The T wave ___________________________________________________________________________________________
85. During review of a chest radiograph, a “snowman sign,” formed by a large supracardiac shadow lying just above the cardiac shadow, is identified. (see image) Which of the following best describes the anatomic anomaly typically associated with this radiographic sign? A. Abnormal development of the pulmonary veins B. Discordant atrioventricular relationships C. Downward displacement of an abnormal tricuspid valve into the right atrium D. Anterior deviation of the infundibular septum E. A single arterial trunk arising from the heart
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86. A 17-year-old girl with no known drug allergies and a prosthetic aortic valve is scheduled for a tonsillectomy and adenoidectomy. Which of the following best describes recommended antimicrobial prophylaxis in this patient? A. Cefixime 400 mg orally, 48 and 24 hours prior to, the day of, and 24 hours after the procedure B. Amoxicillin-clavulanate 875 mg orally, twice daily one day prior to, the day of, and one day after the procedure C. Amoxicillin-clavulanate 1 gm orally, one hour before and one hour after the procedure D. Amoxicillin 2 gm orally, one hour before the procedure E. Amoxicillin 1 gm orally, one hour before and one hour after the procedure ___________________________________________________________________________________________
87. A 20-day-old, severally ill male born at 25 weeks gestation, and undergoing treatment for respiratory distress syndrome, is noted to have a prominent apical impulse, bounding peripheral pulses, and a continuous murmur best heard at the second left intercostal space. The most likely cause of his cardiac findings is best treated with which of the following medications? A. Digoxin B. Indomethacin C. Dexamethasone D. Inhaled nitric oxide E. Prostaglandin E1 ___________________________________________________________________________________________
88. A 6-year-old girl with a history of supraventricular dysrhythmias due to Wolff-Parkinson-White syndrome is also noted on ECG to have a right bundle-branch block and tall peaked P waves in leads II and VI. Which of the following best describes likely findings on echocardiogram in this patient? A. B. C. D. E.
Displacement of the tricuspid valves and a dilated right atrium Ventricular septal defect and dextroposition of the aorta with override of the ventricular septum Juxtaductal aortic coarctation and a bicuspid aortic valve Deformity of the pulmonary valve and right ventricular hypertrophy Increased right ventricular end-diastolic dimensions, flattening and abnormal motion of the ventricular septum, and an atrial septal defect ___________________________________________________________________________________________
89. An obese 14-year-old boy with Type 2 diabetes mellitus returns for follow-up 6 weeks after beginning treatment for primary hypertension. His blood pressure has improved, but he complains of a persistent cough since the onset of treatment. 38
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2014 Pediatrics Board-Style Questions Which of the following classes of hypertensive medications is most likely to cause a chronic cough? A. Diuretics B. Beta-blockers C. Calcium channel blockers D. Angiotensin-converting enzyme inhibitors E. Central alpha antagonists ___________________________________________________________________________________________
90. An 18-year-old male is transported to the emergency room after a syncopal episode. He reports a history of increased fatigue, shortness of breath soon after beginning to exercise, and several recent episodes of hemoptysis. Clubbing is present on physical examination; a right ventricular heave is noted in association with a loud pulmonic component of the second heart sound, and a holosystolic murmur along the left sternal border. Moderate cardiac enlargement, enlargement of the pulmonary vessels in the hilar areas, and relative pulmonary under-vascularity in the outer two-thirds of the lung fields are noted on chest x-ray. Which of the following best describes the likely pathophysiology of this patient’s clinical and radiographic findings? A. High pulmonary vascular resistance B. Anomalous drainage of the pulmonary veins C. Downward displacement of an abnormal tricuspid valve into the right ventricle D. Juxtaductal obstruction and hypoplasia of the transverse aorta E. Left-to-right shunting of blood through an ostium secundum defect and mitral valve insufficiency ___________________________________________________________________________________________
91. An 18-month-old boy is transported to the emergency department following removal from his home due to medical neglect. On physical examination, he appears cyanotic and severely malnourished. His respiratory rate is 38 breaths/minute; heart rate is 140 beats/minute. A gallop rhythm is noted on cardiac auscultation. Chest x-ray reveals cardiomegaly, especially of the right side of the heart. Which of the following vitamin deficiencies is the most likely cause of his symptoms? A. Vitamin A B. Vitamin B1 (thiamine) C. Vitamin B2 (riboflavin) D. Vitamin B6 (pyridoxine) E. Vitamin C ___________________________________________________________________________________________
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Appendix A — Reference Color Photos Adolescence, Question 35
Adolescence, Question 36
Allergy&Immunology/Rheumatology, Question 61
Cardiology, Question 85
Appendix B — Antibiotic Review
Pediatrics Antibiotic Review Short and to-the-point information you need to know ... BETA-LACTAM DRUGS I.
PENICILLINS A. Pen G • Group A Strep (Streptococcus pyogenes) responsible for “strep throat,” toxic shock syndrome, impetigo, and also known as the “flesh-eating bacteria” • Group B Strep (S. agalactiae) in babies and pregnant women • Groups C–G Streptococci (sore throat and occasional blood stream infections) • Human bite or fist wounds (animal bites = amoxicillin-clavulanate) • Gram (+) rods – Listeria causing neonatal and elderly meningitis • S. pneumoniae (30% resistant to penicillin, 10% resistant to 3rd generation cephalosporin) (If worried about meningitis, use vancomycin + 3rd generation cephalosporin) B. Ampicillin • Drug of choice for Enterococcus (+ aminoglycoside, if serious infection or endocarditis) and Listeria • Groups A&B Strep, mouth anaerobes • Always include in an empiric regimen for kids less than 2 months of age with meningitis because of Listeria and Enterococcus • Do not use: No Klebsiella are sensitive C. Piperacillin, Ticarcillin • Called extended spectrum penicillins because they expand gram-negative spectrum to non-beta-lactamase producing GNR—E. coli, Pseudomonas, and anaerobes. Does not cover MRSA. To cover beta-lactamase producers: add a beta-lactam inhibitor (see below) to parent compound. If the organism produces beta-lactamase: • Amoxicillin + clavulanate (Augmentin®) (only oral formulation) • Ampicillin + sulbactam (Unasyn®) (will NOT get Pseudomonas) • Anti-pseudomonal extended-spectra penicillins: o Piperacillin + tazobactam (Zosyn®) (if treating Pseudomonas—higher dose is required) o Ticarcillin + clavulanate (Timentin®) NOTE: NO ORAL PENICILLIN EFFECTIVE FOR PSEUDOMONAS D. Oxacillin & Nafcillin • Methicillin-sensitive Staph (MSSA) and Strep, but not as good for Strep as penicillin (if organism penicillin-susceptible) • NO Enterococcus • NO gram-negatives
Appendix B — Antibiotic Review
II. CEPHALOSPORINS A. 1st Generation: Cefazolin (Ancef®, Kefzol®) • Good for Gram (+) bugs • Osteomyelitis • Strep– Group A • Staph– MSSA & MSSE • Poorer choices: E. coli (50% resistant), Klebsiella B. 2nd Generations: Cefuroxime (Zinacef®) • Much better gram-negative coverage (except Pseudomonas) • Good: Gram (+) (esp. Strep pneumoniae), Groups A&B, MSSA o H. influenzae—but not meningitis! o E. coli and Klebsiella • 2nd Generations do not enter CSF well, so not for meningitis! Cefoxitin and Cefotetan are only cephalosporins that cover anaerobes (esp. gut)!! • ***Side effect of most 2nd generations is prolonged prothrombin time in patients with underlying liver disease or vitamin K deficiency (they inhibit recycling of vitamin K) EXCEPT for cefuroxime. o Board question—patient with underlying liver disease placed on 2nd generation cephalosporin for anaerobic coverage and PT returns out of range C. 3rd Generations: Ceftriaxone (Rocephin®), Cefotaxime (Claforan®), and Ceftazidime (Fortaz®) • Expands spectra for gram-negatives (Ceftazidime includes Pseudomonas, but no longer recommended for empiric coverage for febrile neutropenics.) • Ceftriaxone and Cefotaxime very good against S. pneumoniae (use with vancomycin if treating meningitis) and H. influenzae; ceftazidime poor choice for pneumococcus • Donʼt use for Staph aureus • Drugs of choice for most CNS infections D. 4th Generation: Cefepime (Maxipime®) • Very broad spectrum ICU drug but does not cover most gut anaerobes! • Good for Pseudomonas treatment Ceftaroline (Teflaro®) (Not approved in < 18 years of age) • First cephalosporin that covers MRSA • Approved in adults for pneumonia and skin and soft tissue infections III. OTHER BETA-LACTAM DRUGS A. Monobactams-Aztreonam • Aerobic, gram-negatives only
Appendix B — Antibiotic Review • •
Doesn’t cover Pseudomonas as well as aminoglycosides and very expensive ***Common Board question: Only beta-lactam that can be given if patient has a history of anaphylaxis to penicillins.
B. Carbapenems: Imipenem (Primaxin®) and Meropenem • Very broad spectrum: MSSA, gram (+), gram (-), Pseudomonas, anaerobes • One of few antibiotics still effective in settings of “extended spectrum beta-lactamase production” • ***Will cross Blood Brain Barrier but may induce seizures (mainly imipenem, in 10% of renal failure pts) AMINOGLYCOSIDES Gentamicin, Tobramycin, Amikacin • Aerobic, gram-negatives only • Good choice for Pseudomonas infections! • **Use for Synergy with Beta-Lactams for Enterococcus, and Group B Strep • Streptomycin for use in multi-drug resistant TB and Tularemia • Toxic to otovestibular system and kidneys QUINOLONES Divided into “generations,” like the cephalosporins Don’t use in pregnancy or those under 18 years of age, except approved as 2nd line therapy for urinary tract infections in children. Bioavailability of oral and IV formulations are same, so use PO if gut OK. All quinolones lower seizure threshold and may cause CNS disturbances (dizziness). A. 1st and 2nd generations: Ofloxacin and Ciprofloxacin • Gram-negatives • NO anaerobes • NO PNEUMOCOCCUS • Ciprofloxacin gets chelated by Aluminum, Mg hydroxide and Iron (i.e., antacids and vitamins) and bioavailability is reduced treatment failure • Donʼt use with theophylline • Ofloxacin–can give for Chlamydia (no longer effective for gonorrhea) B. 3rd Generation: Levofloxacin • Much broader spectrum with enhanced pneumococcal activity • Better Gram (+) coverage than ciprofloxacin/ofloxacin • Atypicals like Mycoplasma • Gram-negatives • No Anaerobes • Single mutation in topoisomerase has led to resistant pneumococci. Watch out for this!
Appendix B — Antibiotic Review
C. 4th Generations: Gemifloxacin (Factive®) and Moxifloxacin (Avelox®) • Enhanced pneumococcal activity • Some add anti-staphylococcal activity • Some add anaerobic activity • Known side-effects: Prolongs the QT interval and should be avoided in anybody with long QT, uncorrected hypokalemia, patients receiving antiarrhythmics (procainamide, amiodarone, sotalol). Use with caution with erythromycin, antipsychotics, and tricyclics. • Approved uses: o Gemifloxacin– Good for pneumonia and covers pneumococcus, Haemophilus, Moraxella, Mycoplasma, Chlamydia o Moxifloxacin– Adds anaerobic & anti-Staph activity! Approved for pneumonia, sinusitis, diabetic foot infections, intraabdominal abscesses, complicated skin and soft tissue infections o Gatifloxacin– Adds anaerobic and anti-Staph activity but drug approved for following infections: pneumonia, sinusitis, urinary tract infections, and pyelonephritis, uncomplicated skin and soft tissue infections, and rectal infections. (Gatifloxacin can cause severe derangements in blood glucose and is contraindicated in diabetics!) OTHER ANTIBIOTICS A. Vancomycin • MRSA, MRSE, and ampicillin-resistant Enterococcus • All Gram (+) aerobic cocci and rods, except for lactobacillus • S. pneumoniae meningitis—especially if resistant to beta-lactam antibiotics • NOT for gram-negatives • “Red Man Syndrome” is a side-effect if given too quickly; not an allergy but due to histamine release (treatment: decrease rate of infusion and diphenhydramine). • ***Resistance is quickly emerging in Enterococcus (vancomycin-resistant Enterococcus VRE): quinupristin-dalfopristin (Synercid®) and linezolid (Zyvox®) are approved for VRE infections B. Metronidazole (Flagyl®) • Anaerobes • Amebiasis • Drug of choice for C. difficile colitis–if patient returns with diarrhea, treat again with Flagyl, but if patient returns again with diarrhea, use PO vancomycin • Not for aerobes; ***Flagyl is not for aerobic organisms*** C. Clindamycin • Anaerobes, gram (+) aerobes, good for Staph and Strep • If osteomyelitis and history of anaphylaxis to penicillin—good choice • Community-acquired MRSA skin infections often respond to clindamycin. Some MRSA carry a gene for resistance to both erythromycin and clindamycin that gets turned on when exposed to drug. So, don’t use
Appendix B — Antibiotic Review
•
clindamycin if isolate is resistant to erythromycin on primary susceptibility testing. NOT for MRSA bacteremia in adults
D. Doxycycline • All weird organisms–Tularemia, Ehrlichia, RMSF, Q Fever (Coxiella burnetii) • An inexpensive choice for community-acquired Pneumonia, Strep pneumoniae, Atypicals (IDSA lists as first drug of choice) • Ehrlichia–Monocytic form (Arkansas, Missouri, etc.) and Neutrophilic form (Northeast) E. Macrolides: Erythromycin (EES), Clarithromycin (Biaxin®), and Azithromycin (Zithromax®) • Mycoplasma; Chlamydia; Legionella • High incidence of resistance in S. pneumoniae • Erythromycin is drug of choice for Campylobacter diarrheal illness in children who cannot take quinolones. • Some resistance in Staph and Strep • Azithromycin adds H. influenzae coverage • Binds to 50S subunit • High doses can cause hearing loss. • EES and clarithromycin inhibit cytochrome p450 system, so lots of drug interactions. Azithromycin doesn’t have same profile. • Azithromycin drug of choice for Bartonella henselae (cat-scratch fever) F. Trimethoprim/sulfamethoxazole • Klebsiella and Pneumocystis jiroveci (PCP) • Nocardia (if you see pneumonia with brain abscesses) • Community-acquired MRSA skin infections often respond, if sensitive • NOT for use in MRSA bacteremia • Hyperkalemia in setting of reduced GFR a common side-effect G. Chloramphenicol • RMSF • Anaerobic brain abscesses • Aplastic anemia is potential complication H. Rifampin • Multi-drug resistant TB • Synergy with beta-lactams for MRSA and MRSE endocarditis and prosthetic infections • Prophylaxis for H. influenzae and meningococcus (Neisseria meningitidis) NEWER ANTIBIOTICS (rarely used in children) A. Quinupristin-dalfopristin (Synercid®) • Approved for vanc-resistant Enterococcus faecium bacteremia and skin/soft tissue infections
Appendix B — Antibiotic Review • • • •
It is ineffective against vancomycin-resistant Enterococcus faecalis! Infusion-related myalgia can be severe Central line required for delivery Not for routine use in MRSA bacteremia
B. Linezolid (Zyvox®) • Approved for pneumonia caused by MRSA, MSSA, and S. pneumoniae and complicated skin/soft tissue infections for gram-positive coverage • 100% oral bioavailability, so use PO if gut okay • Myelosuppression (especially thrombocytopenia with complicating GI bleed) is potential complication and is related to duration of use • Contraindicated with use of SSRIs due to increased risk of serotonin syndrome! C. Tigecycline (Tygacil®) • Approved for complicated skin/soft-tissue infections and intraabdominal infections (broad spectrum) • Available only in IV formulation • Related to tetracycline; causes fetal harm and should NOT be given during pregnancy! • May cause tooth discoloration D. Daptomycin (Cubicin®) • Approved for complicated skin/soft-tissue infections caused by grampositives (including MRSA, streptococci and vancomycin-susceptible Enterococci) and MRSA/MSSA bacteremia, including right-sided endocarditis • NOT for use in Staph left-sided endocarditis • NOT for use in pneumonia as drug does not get into lung in high enough levels • Watch for myositis; measure CPK levels in symptomatic people and discontinue if > 1,000 U/L • IV formulation only
