Treatment, Diagnostic Approach, and Long-Term Outcomes of Lance-Adams Syndrome.

Background: Lance-Adams syndrome (LAS) is a rare neurological complication following cardiopulmonary resuscitation. Patients present with action myoclonus within days to months after awakening. There is no established first-line treatment. The objectives of this study were to describe treatments, diagnostic approaches, and long-term clinical outcomes for LAS.

Methods: We performed a retrospective review of patients seen at three tertiary referral hospitals. An electronic database was used to identify all patients diagnosed with LAS from January 1, 2010, to June 30, 2022. Demographics, diagnostics, treatments, and long-term clinical outcomes were extracted. Descriptive statistics were completed to summarize treatments, diagnostics, and clinical outcomes, which were assessed by Cerebral Performance Category (CPC) at 6 months. Symptom control was defined as minimal or no residual myoclonus causing functional impairment on activities of daily living.

Results: Thirty-nine patients met inclusion criteria. A total of 25 patients were diagnosed with LAS during the acute hospitalization after their cardiac arrest, and the rest were diagnosed in the outpatient setting. The most common initial treatment was levetiracetam (n = 26; 67%) followed by valproic acid (n = 4; 10.3%). Most patients initially treated with levetiracetam (n = 22; 85%) or valproic acid (n = 4; 100%) had symptom improvement. Most patients (n = 28; 72%) required a second medication. The most common second-line agent was a benzodiazepine (n = 13; 48%). Thirty-three patients (85%) had improvement of the myoclonus over time. Thirty (77%) were able to achieve symptom control. The median time to achieve symptom control for patients diagnosed in the inpatient setting was 70 days. At the 6-month follow-up, 8 patients (23%) achieved a CPC score of 1, whereas 11 patients (30%) had a CPC score of 2. Thirteen patients (33%) attempted to wean off their medications, of which six patients (46%) were successful.

Conclusions: Most patients with LAS experienced improvement of their myoclonus while being treated with levetiracetam, valproic acid, or benzodiazepines, although multiple medications and long-term treatment were often used. Half the patients attained favorable functional outcomes at 6 months.