Complex Febrile Seizures: Usual and the Unusual.

Febrile seizures account for 2 to 14% of all childhood seizures, and one-third of febrile seizures are complex febrile seizures. Despite this, there is a lack of clinical equipoise in the diagnosis and management of complex febrile seizures and this results in significant practice variability amongst physicians. Although febrile seizures are generally noted to be benign phenomenon, complex febrile seizures carry the risk of subsequent epilepsy. Furthermore, long-term neurodevelopmental sequelae have been observed in some cohorts. The presence of both simple and complex febrile seizures have also been documented in sudden unexpected death in childhood cohorts, and there may be similarities in the underlying pathophysiology to sudden unexpected death in epilepsy. Finally, in some cases the presence of complex febrile seizures may herald the onset of a devastating developmental and epileptic encephalopathy (i.e., Dravet syndrome) or Febrile-Infection Related Epilepsy Syndrome (FIRES). In this narrative review the authors explore the current state of management of complex febrile seizures, their neurological sequelae and morbidity as well as rare epilepsy syndromes and conditions associated with them.