creation date: 2026-09-16 19:08
tags: Workups
Fever (Pediatrics)
Background
Fever is the abnormal elevation of body temperature that occurs as part of a biologic response controlled by the CNS.
Hyperthermia refers to temperature raise due to head production that exceeds the body’s capability to dissipate heat. It does not respond to antipyretic agents.
Pathophysiology
Fever is a result of a series events that has to do with interleukin-1, 6, TNF, interferon-alpha, and other pyrogenic cytokines. These cytokines increases the synthesis of prostaglandin. In particular, prostaglandin E2 in the brain raises the hypothalamic set-point for body temperature.
The potential benefit of fever includes decreased growth and reproduction of bacteria and viruses. However, fever can cause increased metabolic rate, oxygen consumption, and carbon dioxide production. It can also increase the demand on CV and resp systems.
Differential Diagnosis
Initial Evaluation
Temperature measurements are typically measured via the rectum, mouth, and axilla. However, other options include the tympanic membrane or forehead.
- For infant: ≥38C rectally is concerning
- For 3-36 months: 38-39C is fever, concerning if ≥39C and no focus of infection on exam
- Older children: fever defined as ≥37.8-39.4C orally
The evaluation of fever in the pediatric population depends on their age and comorbidity.
Generally, the goal of evaluation is to identify underlying disease and/or a source of infection.
Investigations
Laboratory studies
- CBC with differential
- Electrolytes
- Creatinine
- CRP
Cultures
- Urinalysis and urine culture
- Throat culture
- Blood culture