Background: Clinical phenotypic expression of SSADH deficiency is highly heterogeneous, and some infants may develop refractory secondary generalized seizures.
Patient: A 9-month-old boy manifested partial seizures, developing severe status epilepticus, and conventional antiepileptic drugs were ineffective. Use of ketamine contributed to the control of status epilepticus, achieving a reduction in frequency of partial seizures, and improving EEG findings without apparent complications. Diffusion-weighted images showed hyperintensities in the bilateral basal ganglia and fornix, and multiple T2 hyperintensity lesions were detected. (123)I-iomazenil (IMZ) SPECT revealed a decrease in binding of (123)I-iomazenil predominantly in the left temporal region by the 18th day of hospitalization. However, repeated IMZ-SPECT on the 46th day of hospitalization demonstrated almost no accumulation across a broad region, sparing the left temporal region. The patient showed rapid regression, refractory myoclonus, and severe progressive brain atrophy.
Conclusion: IMZ-SPECT findings demonstrated reduced benzodiazepine receptor binding and its dynamic changes in an SSADH-deficient patient. Considering the down regulation of the GABAA receptor, ketamine should be included in pharmacotherapeutic strategies for treatment of refractory status epilepticus in SSADH-deficient patients.
Keywords: (123)4-Hydroxybutyric aciduria; Gamma-hydroxybutyric aciduria; Ketamine; Refractory status epilepticus; SSADH deficiency.
Copyright © 2016 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.