CASE HISTORY 1: a 34 year old right handed African American female developed intermittent horizontal diplopia followed by weekly recurrent gasping for air and choking while eating Episodes resolved after 1-2 minutes. Initial diagnosis was asthma but inhaler gave no relief. About 16 months later, ACHR antibody panel was negative.
With continued episodes, MuSK antibody panel was positive at 1:2560. Over 6 months, she further noted dysphagia, facial weakness, and persistent diplopia. Occasionally when drinking liquids, fluid came out her nose. She developed neck and extremity weakness worse at end of day. Trapezius 3 HZ repetitive nerve stimulation (RNS) demonstrated a 14% decrement. Chest CT was negative for thymoma but showed a small thyroid nodule. She improved with initiation of prednisone 30 mg daily and Mestinon 60 mg daily. After several months trapezius RNS demonstrated a 13.4% decrement and post activation exhaustion of 18.6%. MMT was 26 and plasmapheresis produced resolution of symptoms at 1 month followup. Cellcept 1000 mg BID was added and prednisone 60 daily continued with stable improvement.
CASE HISTORY 2: A year prior to symptom onset of Case 1, her brother, a 31 year right handed male, developed similar episodic weakness including symptoms of fatigue late in the day. Workup yielded a negative ACHR antibody panel; however MuSK antibody panel was positive. His diagnosis and response to therapy led to the evaluation and treatment for his sister later that year. He is stable by history and medical record review from another location.