Pedia: Fever

1

YOU GIVE ME FEVER!!!

•

•

•

•

•

By Lester A. Deniega, MD

Thermosensitive neurons (Anterior hypothalamus)

(Pedia2 Module4/ Lecture Date: June 15, 2006)

FEVER

Fever definition o Elevation of body temperature to above normal (98.40F) or 370C orally or 99.80F or 37.60C rectally) Challenge to fever o To establish the causative agent – distinguish viral from bacterial disease o Identify the site of a localized infection Temperature Variability o Individual to individuals o In each individual o Diurnal variation in temperature o Oral, axillary or rectal temperatures o Responses among children and adults o Physiologic states causing fever:  digestion  exercise  ovulation  pregnancy  warm environment  emotion o Pathologic causes  Infection  Inflammation e.g. connective tissue disease  Neoplasms  Vaccines  Dehydration Common causes of fever o Minor illness  URTI  Viral exanthems  Gastroenteritis o Major illnesses  Bacterial meningitis  UTI  Pneumonia  Malaria Mechanisms of a Protective Effect of Fever o Enhanced neutrophil migration o Increased production of antibacterial substances by neutrophils o Increased production of interferon o Increased antiviral and antitumor activity of interferon o Increased T-cell proliferation o Decreased growth of microorganisms in iron-poor environment

Thermoregulatory responses: Redirection of blood to and from Cutaneous vascular beds  Increased or decreased sweating  ECF volume regulation  Behavioral changes Why Fever Occurs Exogenous pyrogens: e.g.infectious agents, drugs 

•

White blood cells (macrophages, monocytes, neutrophils) Cytokines e.g. IL-1, TNF Hypothalamus in brain Prostaglandins FEVER •

Fever patterns o Intermittent – high spikes with return to normal o Remittent – like intermittent but temperature never returns to normal o Sustained – like remittent but with less marked swings of temperature o Relapsing – several days of fever alternating with periods of normal temperature

•

Fever patterns suggesting specific diseases o Sustained - typhoid fever o Remittent – abscess o Relapsing – B. recurrentis; Hodgkin’s disease (noninf.)

•

Spectrum of fever syndromes o Fever without localizing signs o Fever of short duration associated with infection o Recurrent and prolonged fever associated with infection o Fever with a rash o Fever in association with a chronic disease o Fever associated with a collagen disease o Fever associated with malignancy o Drug fever o Factitious fever o Hospital-acquired

•

Fever associated with a chronic disease Chronic disease 

“Fever”: Infectious Disease Clinics Of North America, 1995

•

 Extreme hyperpyrexia and hypothermia (>410C) 

Extreme pyrexia

Hypothermia



 

    

•

Central fevers (neoplastic, trauma or infection) Drug fever Heat stroke HIV Malignant hyperthermia Malignant neuroleptic syndrome

   

Elderly Cold exposure Hypothyroidis m Overwhelming infection Sepsis in CRF Overzealous treatment with antipyretics

  

 •

Pathogenesis of fever Exogenous pyrogens: Microbes, microbial toxins, Other microbe products Endotoxins PML, Monocytes, Macrophages Endogenous pyrogens: IL-1;IL-6;TNF-a & IFN –B and Y

•

Complications

Congenital heart disease Cyanotic heart disease Rheumatic fever



Bacterial endocarditis

 

Shunted hydrocephalus Chronic renal disease Congenital or acquired immunodeficiency



Cerebral abscess Bacterial endocarditis, recurrence of RF Shunt infection, sepsis Urinary tract infection Opportunistic organisms, fungi, parasites Concealed abscess

Recent surgery

 



Drug fever o 1-2% of prolonged fevers o Penicillin o Sulphonamides o Cephalosporins o Amphotericin B o Anticonvulsants o Atropine o Blood and plasma derived products History Specific points of importance:

2 o o o o o o o o

Child’s appetite, thirst, sleep pattern, weight loss, play activities, motor abilities and behavior Water supply and methods of preparing food and formula Area of residence or areas visited - knowledge of epidemiology Health of immediate family-members, caregivers and relatives Contact with pets, birds and other animals. Medication history pursued Past history of surgery, congenital defects, chronic illness and infections Family history for genetic disorders

PHYSICAL EXAMINATION

MANAGEMENT OF FEVER •

Why Treat Fever  Comfort to the child  Prevention of febrile convulsions  Decreased parental anxiety  Helpful when child has underlying illness e.g. heart disease

•

American Academy of Pediatrics Recommendations  A child older than 6 months of age who has a temperature below 38.30C probably does not need to be treated for fever, unless the child is uncomfortable. Observe her behavior. If she is eating and sleeping well and is able to play, you may wait to see if the fever improves by itself.  Keep the room comfortably cool  Dress child in light clothing  Encourage child to drink fluids such as water, diluted fruit juices, or a commercially prepared oral electrolyte solution  Be sure that she does not overexert herself  Medications can be given to reduce temperature if child is uncomfortable

Should be systematic, meticulous and convincing to the parents • •

•

Observe general appearance, demeanor Localize the lesions or note for any specific local signs or symptoms Look for subtle signs of CNS involvement Note for skin rashes and classify Occult blood in stools Muscles and skeletons carefully palpated for generalised or localised tenderness or swelling. Note for joint tenderness and function Enlargement: liver, spleen,lymph node After full examination of abdomen,chest and heart, focus attention on EENT Pelvic examination for sexually active females

•

Tell-tale clues

• • • • • •

Red weeping eyes Bulbar conjunctivitis Lack of sweating Palpebral conjunctivitis Choroid tubercles Sinus tenderness Muscle tenderness Sore trapezius muscle Dental examination Normal pulses despite high fever •

 

Periarteritis nodosa Leptospirosis moderate to severe dehydration; anhydrotic ectodermal dysplasia EBV infection, TB and SLE, Catscratch disease TB sinusitis Trichinosis, viral infections, Collagen-vascular diseases subdiaphragmatic abscess abscesses Factitious fever









Findings that Localize Infection Sore throat Cough, rusty sputum Severe joint pain/swelling Severe pain in head and back of the neck with stiffness Severe pain in a bone Tender liver Ill-defined skin and soft tissue inflammation Bloody diarrhea

Streptococcal tonsillitis; diphtheria Pneumonia pyogenic arthritis Meningitis Osteomyelitis amebic liver abscess; viral hep Cellulitis; pyomyositis Shigella; Campylobacter

•

Approach to Diagnosis of Infectious Disease o All abnormalities and pathophysiologic changes are documented o The anatomical site of infection is determined o Identification of etiologic agent  Many pathogens tend to infect specific tissues or organs o Only when agent is identified can a tentative diagnosis become definitive

•

Investigations o Nonspecific e.g. WBC and differential, ESR, Imaging studies o Laboratory investigations in microbiology  Direct microscopy  Culture & sensitivity testing  Detection of antigen/antibody

Be sure to follow the correct dosage and medication schedule as any medication can be dangerous if you give your child too much. Ibuprofen should only be used for children older than 6 months of age. It should not be given to children who are vomiting constantly or are dehydrated. Do not use aspirin to treat your child's fever. Aspirin has been linked with side effects such as an upset stomach, intestinal bleeding and, most seriously, Reye syndrome. Do not use cold water to sponge your child, as this could cause shivering. That could increase her temperature. Never add alcohol to the water. Alcohol can be absorbed into the skin or inhaled, causing serious problems such as a coma. Do not try to reduce your child's temperature to normal too quickly. This could cause the temperature to rebound higher.

•

Antipyretics: Paracetamol (acetaminophen)  Dose: 10 – 15 mg/kg/dose q 4 hrs  Least toxic  Toxic range is 10 times the normal dose range  Well tolerated  Very few allergic reactions

•

Specific Treatment o Not all fevers are caused by infections o Not all infections are bacterial in origin o Some bacterial infections are better treated by other means e.g. abscess

•

Considerations in Choosing an antibiotic o The microorganism  Bacteriological results interpreted in the light of clinical findings o The host e.g. genetic factors, physiologic functions, site and severity of infection and allergy o The antibiotic – pharmacokinetic properties  Monotherapy vs. Antibiotic combinations  Whenever an alternative is available, the cheaper antibiotic selected /3na/secb08