Post-Anoxic Reticular Reflex Myoclonus in a Child and Proposed Classification of Post-Anoxic Myoclonus

Area of Science:

• Neurology
• Neurophysiology

Background:

• Post-anoxic myoclonus is a complex neurological condition following hypoxic-ischemic encephalopathy.
• Understanding the specific mechanisms and classifications is crucial for diagnosis and management.

Observation:

• A nine-year-old boy experienced epileptic spasms, generalized myoclonus, and dystonia after submersion-induced hypoxic-ischemic encephalopathy.
• Electromyography (EMG) polygraphy revealed myoclonus discharges <50 ms, with no cortical correlates.
• EMG findings indicated a brainstem generator, consistent with reticular reflex myoclonus.

Findings:

• Reticular reflex myoclonus was identified in a pediatric patient with hypoxic-ischemic encephalopathy.
• Neurophysiological assessment confirmed a brainstem generator for the myoclonus.
• Clonazepam effectively treated both myoclonus and dystonia, though the patient remained in a persistent vegetative state.

Implications:

• Reticular reflex myoclonus is identifiable in children through neurophysiological studies, similar to adults.
• This condition in children carries a similarly poor prognosis.
• Post-anoxic myoclonus encompasses various mechanisms and should be differentiated from Lance-Adams syndrome.