Chronic posthypoxic myoclonus: Lance-Adams syndrome

Lance-Adams syndrome (LAS) is a rare condition described as chronic intentional myoclonus following prolonged hypoxia. With limited cases of the condition, no standardised diagnostic criteria, and features overlapping acute myoclonus status epilepticus (MSE), diagnosis and management are challenging.Our case is a man in his 20s, who was admitted to the intensive care unit following two in-hospital cardiac arrests. He consequently developed persistent generalised myoclonic seizures despite multiple antiepileptics and sedation. CT, MRI and electroencephalogram (EEG) ruled out a diagnosis of MSE, making LAS more likely. Ketamine was ultimately required to terminate the generalised myoclonic seizures after which antiepileptic drugs were optimised to reduce residual intention myoclonus.This report highlights key features prompting the clinical suspicion of LAS in a patient who has no significant evidence of brain injury, preserved consciousness with continued severe generalised myoclonus and outlines pharmacological and neurophysiological management.