Prevalence, Clinic-Etiological Spectrum and Outcome of Pediatric Metabolic Epilepsy - A Single Centre Experience

Inborn errors of metabolism (IEM) are a rare cause of epilepsy in pediatric age group. Prompt diagnosis is essential, as some of these disorders are treatable.

To determine the prevalence, clinical, and etiological profile of metabolic epilepsy in children.

A prospective observational study of children with new onset seizures diagnosed as inherited metabolic disorder in a tertiary care hospital, South India.

Among 10,778 children with new onset seizures, 63 (0.58%) had metabolic epilepsy. The male female ratio was 1.3:1. Onset of the seizures were in neonatal period in 12 (19%), infancy in 35 (55.6%), and between one and 5 years of age in 16 (25.4%) children. Generalised seizures were seen in 46 (73%), followed by multiple seizure types (31.7%). The associated clinical features included developmental delay in 37 (58.7%), hyperactivity in 7 (11%), microcephaly in 13 (20.6%), optic atrophy in 12 (19%), sparse hair and/or seborrheic dermatitis in 10 (15.9%), movement disorder in 7 (11%), and focal deficit in 27 (42.9%) patients. Magnetic resonance imaging brain was abnormal in 44 (69.8%) and diagnostic in 28 (44.4%) patients. Causative metabolic errors included vitamin responsive errors in 20 (31.7%), disorders of complex molecules in 13 (20.6%), amino acidopathies in 12 (19%), organic acidemias in 10 (16%), disorders of energy metabolism in 6 (9.5%), and peroxisomal disorders in 2 (3.2%) patients. With specific treatment, seizure freedom could be achieved in 45 (71%) children. Five children lost to follow-up and two died. Among the remaining 56 patients, 11 (19.6%) had a good neurological outcome.

Vitamin responsive epilepsies were the most frequent cause of metabolic epilepsy. Early diagnosis and prompt treatment is necessary as only one-fifth had a good neurological outcome.