Mortality after febrile seizures was studied in a large population-based cohort of children in Denmark followed from 3 months of age up to 25 years or until death, by researchers at Institute of Public Health, and National Centre for Register-based Research, Aarhus University; and University Hospital, Aarhus, Denmark; and School of Public Health, UCLA, USA. Of 1.6 million children born between 1977 and 2004, 8172 died, including 232 deaths in 55,215 children with a history of febrile seizures. The mortality rate ratio (1.80) was 80% higher during the first year and 90% higher (1.89) during the second year after the first febrile seizure; 132 of 100,000 children died within 2 years of a febrile seizure compared with 67 deaths per 100,000 without a history of febrile seizures. The increase in mortality (rate ratio 1.99) was restricted to patients with complex febrile seizures (>15 min or recurrence within 24 hr); children with simple febrile seizures (<15 min and no recurrence within 24 hr) had a mortality rate similar to the background population (rate ratio 1.09). The cause-specific cumulative mortality within 2 years of a febrile seizure per 100,000 children was 13 for seizures, 11 for pneumonia, 11 for sudden unexpected death, and 11 for congenital malformation of the nervous system. The development of epilepsy was not the explanation for increased mortality in all cases. The risk of sudden unexpected death was five times greater during the 2 years after a first febrile seizure than in the background population. 
COMMENT. An increased risk of mortality in children with a history of febrile seizures is restricted to patients with complex febrile seizures. The risk though significant is small, but the cause is not completely understood. The occurrence of epilepsy or neurologic abnormality may be contributory in some but not in all deaths. Mazumdar M in a commentary  recommended further follow-up of complex cases. Kinney H et al.  relates sudden death in 5 toddlers with febrile seizures to developmental hippocampal pathology and possible nocturnal seizures. A shared susceptibility to SIDS and febrile seizures has not been proven. That febrile seizures may be less benign than generally assumed is suggested by the above study and also by the recent report of MRI abnormalities in patients with first simple or complex febrile seizures . In practice, MRI is not indicated for the evaluation of simple febrile seizures, but neurologic consultation is advisable in children with recurrent febrile seizures and in those with complex seizures. (Ped Neur Briefs June 2008;22:47-48).
Omega-3 fatty acids recommended in treatment of refractory seizures and in prevention of sudden unexpected death in epilepsy . The recommendation is based on clinical and animal studies that have demonstrated anticonvulsant properties of omega-3 supplementation and a reduction in cardiac arrhythmias and sudden cardiac deaths, the proposed mechanism of sudden death in epilepsy.