What is a likely cause of a tonic-clonic seizure in an infant with no seizure history?

A tonic-clonic seizure in an infant with no previous seizure history is most commonly associated with a fever, particularly in young children. This phenomenon is known as a febrile seizure, which typically occurs in response to a rapid rise in body temperature, often due to an infection. Infants are especially susceptible to febrile seizures between the ages of 6 months and 5 years, as their developing nervous systems can react dramatically to systemic illnesses that cause fever.

Fever is a well-documented and recognized trigger for seizures in infants and young children, and it is often benign, resolving once the underlying cause of the fever is treated. In contrast, status epilepticus refers to a series of seizures without regaining consciousness in between, which is a more severe condition and not likely to be the first presentation for an infant without seizure history. The old formula and tumors could also provoke seizures but are less common and not the first consideration in a sudden instance of a tonic-clonic seizure in an infant. Often, a febrile seizure occurs without any additional underlying health problems, especially if the infant exhibits otherwise normal development prior to the event.