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Fever in children Mostafavi SN, MD Pediatric infectious disease department Isfahan University of Medical Sciences 1396/01/14

At the end of class you would be able to: Definition of fever. Measurement of fever by all types of thermometer. Definition and types of hyperthermia. Mechanism of fever. Indications of antipyretic therapy Ways for control of fever. 1396/01/14

Hypothalamic set point Perception of body temperature from: Blood temperature Cold and warm receptors of skin and muscles Regulation by: Peripheral vasodilation/ vasoconstriction Sweeting Heat production in muscle and liver Behavioral response by seeking a cooler or warmer environment 1396/01/14

Normal body temperature Axillary( 1-5 yr.) T< 36.8⁰C in morning 0.5 ⁰C higher in oral( >5 yr.) 1 ⁰C higher in rectal(<1-3 yr.) 0.5 ⁰C higher at other times( circadian rhythm) 1396/01/14

Types of thermometer 1396/01/14

Elevated body temperature Fever: change in hypothalamic set point( till 41ºC) Hyperthermia: Environmental heat: heat stroke Excessive heat production: malignant hyperthermia (anesthetic drugs) or Neuroleptic malignant syndrome (antipsychotic drugs), thyroid storm Defective heat loss: dehydration+ over clothing, anti- cholinergic drugs, Ectodermal dysplasia, familial dyautonomia 1396/01/14

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Mechanism of producing fever Heat production: Increased metabolism of body ( ↑T4, ↑cortisol, …) Increased muscle tone and activity Heat conservation: Peripheral vasoconstriction Behavioral changes 1396/01/14

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Other effects of fever Shivering chills Constitutional symptoms: headache, anorexia, nausea, vomiting, myalgia, arthralgia Somnolence Decrease serum iron and zinc levels Increased heart rate and respiratory rate 1396/01/14

Benefits and harms of fever Uncomfortable for patients in fever> 39ºC Exacerbate chronic disorders( cardiac, pulmonary, metabolic, seizure) Benefits: Decrease microbial replication Enhanced immunologic function 1396/01/14

Management of fever phobia Fever is a physiologic response not an illness Most fevers are benign Fever not make the illness worse The height of the fever is less important than other signs of serious illness Febrile convulsion is age dependent, and often a familial benign disorder Antipyretic therapy not decreases the recurrence of FC Initial measures is extra fluids and reduced activity Antipyretics if the child is uncomfortable (decreased activity or fluid intake, etc) No need to measure the fever after antipyretics No need to awaken the children for antipyretics 1396/01/14

Indications of antipyretic therapy High fever (ie, ≥40ºC ) Discomfort Chronic cardiopulmonary, metabolic, renal, neurologic disorders 1396/01/14

Control of fever Acetaminophen Ibuprofen No aspirin , diclofenac Na and other NSAIDS No corticosteroid No complementary and alternative therapy remedies External cooling : in hyperthermia, very young infants, severe liver disease 1396/01/14

Acetaminophen Choice of antipyretic therapy due to long-lasting safety Peak effect in 3-4 hr. The duration of action: 4-6 hr. Usually safe with no adverse effects 1396/01/14

Iboprufen Slightly more effective and longer-lasting than acetaminophen Duration of action: 6-8 hrs Not recommended in < six mo. Adverse effects: gastritis, gastrointestinal bleeding, acute kidney injury With appropriate doses and if taken with food usually is safe 1396/01/14

External cooling If more rapid and greater reduction of temperature is necessary At least 30 minutes after antipyretics Comfortably warm or tepid water (generally around 30ºC ) Alcohol should not be used 1396/01/14

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