Fever is generally defined as a temperature of ≥38.0°C (100.4°F) and is one of the most common reasons why children and their carers seek medical attention

Pathophysiology

Endogenous or exogenous pyrogens trigger release of prostaglandins, most notably prostaglandin E2, which in turn signals the hypothalamus to elevate the body's thermoregulatory set-point by regulating endocrinological, autonomic, and behavioural responses.

However, normal body temperature varies substantially by factors such as the time of day, degree of physical exertion, and ambient temperature.

Differential diagnosis

• Viral infection - Croup, bronchiolitis
• Otitis media
• Tonsillitis
• Pneumonia
• UTI
• Septicaemia/sepsis
• Meningitis
• Non infective causes - Kawasaki disease, Post immunisations (MenB), Autoimmune (SLE, IBD)
• Malignancy - Leakemia, NHL

Traffic light system for risk stratification

Record the following in all febrile children:

• temperature