Abstracts

Rationale: In 1963, Lance and Adams first described a syndrome of myoclonus triggered by voluntary movements after hypoxic brain injury with recovery of consciousness. Several cases of Lance Adams syndrome (LAS) have been reported which include a period of unconsciousness, followed by recovery of consciousness and myoclonus. The myoclonus is provoked by sensory stimuli or when the affected patient is attempting to initiate movement.  However, an acute form of post-hypoxic myoclonus exists as well. The onset is generally within 48 hours of the hypoxic injury while the patient is still comatose, and its presences suggests a poor prognosis. However, a few cases have been reported with good recovery, mostly following treatment with a hypothermic protocol.  The full spectrum of acute versus chronic post-hypoxic myoclonus is not described, likely because of areas of overlap.  Understanding this spectrum may have important implications for prognostication of patients with post-hypoxic myoclonus. Methods: We present a case of post-hypoxic myoclonic status epilepticus suggestive of poor prognosis, however, the patient regains consciousness and continues to good recovery.  This favorable clinical course evolves despite the patient not undergoing hypothermic treatment. Results: A 23-year-old female suddenly became unresponsive and apneic shortly after self-injection of heroin.  In the emergency department, she was found to have persistent myoclonic jerking that stopped with propofol sedation. On initial work-up, a computerized tomography of the brain showed no acute process.  Electroencephalography (EEG) demonstrated generalized rapid spike discharges associated with myoclonic jerking (figure 1).  Spike activity was separated by brief periods of generalized suppression or runs of anteriorly maximal beta.Neurologic exam was performed on propofol due to continuous myoclonus, and revealed the patient did not have any spontaneous or pain-induced movements of the limbs, or brain stem reflexes. She was kept on continuous video EEG monitoring for seven days. Myoclonic activity was initially treated with levetiracetam, phenytoin, and propofol.  Due to continued myoclonus, the patient was treated with pentobarbital-induced burst suppression for 48 hours. When pentobarbital weaned, myoclonic activity was then discontinuous, and to a greater intent with stimulation including voice or other sounds, endotracheal tube suction or touch.  Anti-epileptic medications (AED) included valproic acid, lacosamide and levetiracetam.    Brain magnetic resonance imaging (MRI) was performed on day 4 and day 8 and did not demonstrate acute intracranial abnormalities.  On day 7, her exam was mostly unchanged but flexion to noxious stimuli was seen in both lower extremities.  EEG at that time demonstrated a poorly sustained 4-6 hertz background (figure 2) in the absence of myoclonic jerking.  MR spectroscopy of the brain was completed on hospital day 13 and demonstrated mild reduction in the N-acetylaspartate(NAA) peaks within the sample regions of the basal ganglia.Gradually, myoclonic activity lessened and propofol was stopped.  On hospital day 28, patient opened her eyes to voice and followed commands.  By hospital day 42, she was awake and alert, able to speak and walk with two-person assistance.   The patient continued to have myoclonic jerks of arms, legs, and face, mostly with intention.   On hospital day 45, she was discharged to a rehabilitation facility. Chronic AED utilized were levetiracetam and clonazepam. Conclusions: Our case and others suggest that patients with post-hypoxic myoclonic status epilepticus can achieve good recovery.  Reporting such cases helps to shape future standardized guidelines on post-hypoxic injury prognosis. Funding: none