What causes fainting in children with fever?

Febrile syncope in children typically refers to febrile seizures. Febrile seizures in children may result from immature brain development, hypoxia, or genetic factors.

1. Immature Brain Development

In some younger children, a high fever—especially when exceeding 38°C—can affect the hypothalamic thermoregulatory center in the brain, potentially triggering shock and subsequent seizures.

2. Hypoxia

A rapid rise in body temperature during fever may compromise cerebral blood flow, leading to cerebral hypoxia, which in turn can readily precipitate seizures.

3. Genetic Factors

Seizures exhibit a degree of familial inheritance. For instance, if either parent has a history of seizures, the child may inherit a predisposition to febrile seizures between ages 6 months and 6 years. These episodes commonly manifest as limb convulsions and loss of consciousness. However, such febrile seizures are usually brief—lasting no more than five minutes—and generally resolve spontaneously without requiring specific treatment.