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

1. a Dehan M, Quillerou D, Navelet Y, D'Allest AM, Vial M, Retbi JM, Lelong-Tissier MC, Gabilan JC. [Convulsions in the fifth day of life: a new syndrome?]. Arch Fr Pediatr. 1977 Oct;34(8):730-42.
[PMID: 931532]
2. a Pryor DS, Don N, Macourt DC. Fifth day fits: a syndrome of neonatal convulsions. Arch Dis Child. 1981 Oct;56(10):753-8. doi: 10.1136/adc.56.10.753.
[PMID: 7305412] [PMCID: 1627317] [DOI: 10.1136/adc.56.10.753]
3. a, b Panayiotopoulos CP. (2005). The Epilepsies: Seizures, Syndromes and Management. Oxfordshire (UK): Bladon Medical Publishing
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