Hemispheric polymicrogyria and neonatal seizures: a potentially life-threatening combination
Paula M Brna1, A Simon Harvey2, Richard J Leventer2
1Department of Neurology, The Royal Children's Hospital, Melbourne, Australia, IWK Health Centre, Halifax NS and Dalhousie University, Halifax, Nova Scotia, Canada.
Insights
Severe polymicrogyria (PMG) in one brain hemisphere can cause drug-resistant seizures in both hemispheres, leading to early death. This highlights a critical, severe phenotype of unilateral PMG.
Area of Science:
- Neurology
- Developmental Neuroscience
- Pediatric Neurology
Background:
- Polymicrogyria (PMG) is a brain malformation with excessive gyration and abnormal cortical lamination.
- While bilateral PMG often causes severe developmental delay and epilepsy, the full spectrum of unilateral PMG severity is not well-defined.
Observation:
- Two cases of right hemispheric PMG presented with neonatal-onset, intractable seizures.
- Seizures began within the first days of life and were resistant to multiple antiepileptic drugs.
- Both infants experienced seizures originating independently in both hemispheres, requiring intensive care.
Findings:
- Despite aggressive treatment, including functional hemispherectomy in one case, both infants died due to refractory seizures.
- The severe phenotype included drug-resistant epilepsy and, in one case, prolonged ictal apneas requiring respiratory support.
- These cases demonstrate a severe presentation of unilateral PMG associated with bilateral seizure activity.
Implications:
- Unilateral PMG can manifest with a severe, bilateral seizure phenotype, challenging typical understandings of PMG's impact.
- Early-onset, drug-resistant epilepsy in unilateral PMG warrants aggressive investigation and management strategies.
- These findings underscore the critical need for further research into the mechanisms and treatment of severe PMG phenotypes.
Abstract:
Polymicrogyria (PMG) is a heterogeneous malformation of cortical development characterized by excessive gyration and abnormal cortical lamination. Typically, bilateral forms have more severe developmental delay and early-onset epilepsy, but the full spectrum of severity remains ill-defined. We report two cases of right hemispheric PMG and neonatal-onset, drug-resistant seizures culminating in early death. Case 1 began having seizures on Day 1 of life that intensified in severity and proved resistant to numerous antiepileptic drugs. He underwent right functional hemispherectomy but died three weeks post-operatively due to ongoing seizures. Case 2 presented with seizures on Day 3 of life and required respiratory support for prolonged ictal apnoeas. Seizures were resistant to antiepileptic drugs and eventually led to respiratory arrest, once aggressive resuscitative measures were withdrawn. In both cases, seizures seemingly originated independently in both hemispheres. These cases represent a severe phenotype of unilateral hemispheric PMG with bilateral seizures.
