Benign nonfamilial neonatal seizures

Benign neonatal seizure (nonfamilial) is a benign syndrome characterized by clonic seizures that begin around the fifth day of life and may recur during the following 2 to 3 days.

• Dehan et al 1977^[1] first reported a neonatal convulsive disorder of unknown etiology that occurs around the fifth day of life and associated with a favorable outcome.
• Prior & Macourt (1981)^[2] described the features in 90 infants with the condition and coined the term “fifth day fits”
• In 1989, the ILAE Commission on Classification and Terminology proposed the term “benign neonatal seizures”
• The updated ILAE 2017 classification categorizes it under Conditions with epileptic seizures that are traditionally not diagnosed as a form of epilepsy per se.

• Claes et al 2004 reported three de novo mutations in KCNQ2 in 4 patients with benign neonatal seizures without a family history (Claes et al 2004).
• Ishii et al 2009 also reported another de novo mutation was reported in a neonate with benign neonatal seizures and no family history of seizures.
• KCNQ2 variants have been described in patients with benign familial neonatal seizures suggesting an overlap between the 2 syndromes.

• seizures are mainly clonic
• median duration is around 20hrs (status epilepticus)^[3]
• onset is around fifth day of life

• ictal EEG usually shows localised spikes
• interictal EEG usually shows theta pointu alternant. It may also show focal or multifocal, non-specific abnormalities or a discontinuous pattern or it may be normal in ~10%.

• probably environmental

• Benign familial neonatal epilepsy
• Benign familial infantile epilepsy
• Benign infantile epilepsy

• excellent with risk of subsequent seizures practically nil(0.5%)^[3]
• normal neurodevelopmental outcome