‘Pseudo‐ataxic’ negative myoclonic status in developmental and epileptic encephalopathy with spike‐wave activation in sleep: Utility of ACTH therapy beyond west syndrome

BACKGROUND: Developmental/Epileptic encephalopathy with spike and wave activation in sleep (DEE-SWAS) comprises a spectrum of childhood-onset epilepsies, characterized by near-continuous spike-wave discharges during non-REM sleep which can result in cognitive, behavioral, and motor regression. Negative myoclonic status in the context of DEE-SWAS is extremely rare, and management is difficult as conventional anti-seizure medications (ASM) and immunomodulatory therapies often show limited efficacy. Adrenocorticotropic hormone (ACTH), classically used for infantile spasms, has recently been reported as a potential therapy for refractory DEE-SWAS. CASE PRESENTATION: We report a 7-year-old girl with prior developmental encephalopathy, who experienced recurrent unprovoked seizures from 5 years of age, followed by progressive ataxia and language regression. Clinical examination revealed facial dysmorphism, truncal and gait ataxia, oral apraxia with atonic head drops. Video EEG revealed background slowing with bilateral centro-parieto-temporal spikes markedly activated in sleep, with clusters of atonic neck and truncal drop seizures suggestive of negative myoclonic status leading to 'pseudo-ataxia'. Despite treatment with multiple ASM, intravenous methylprednisolone and immunoglobulin, there was worsening encephalopathy and anterior opercular syndrome. Given therapeutic refractoriness, ACTH was initiated. The patient showed dramatic improvement: resolution of status, a marked reduction in EEG spike-wave burden, recovery of gait and language to baseline, and restoration of social interaction. CONCLUSION: This case demonstrates for the first time the potential of ACTH in refractory DEE-SWAS with negative myoclonic status epilepticus, wherein conventional immunomodulation fails. The sustained clinical and electrographic improvement highlights the broader neuro-modulatory mechanisms of ACTH and supports its consideration in treatment algorithms. Larger prospective studies are warranted to compare the efficacy and safety profile of various corticosteroids in DEE.