Tyler Kemnic^1,, James Choi¹, Samanjit Kandola¹, Khader Herzallah¹

A 29-year-old female G2P2 with a past medical history of hyperthyroidism and depression was admitted for 2-months of progressively worsening weakness of her bilateral upper and lower extremities. Initial investigations were unremarkable, and the patient’s weakness improve the next morning. The patient was thought to have a Somatoform Disorder and was planned for home discharge, however on the day of discharge her magnesium was 1.2 mg/dL. After repletion, she developed seizure-like activity and respiratory failure, requiring mechanical ventilation and transfer to the ICU. In ICU, patient received another dose of replacement magnesium that caused another seizure, code blue and re-intubation. Subsequent lab work revealed reactive Acetylcholine receptor antibodies and subsequent chest imaging demonstrated thymoma, confirming a diagnosis of Myasthenia Gravis in Crisis. The patient improved following plasma exchange and was discharged home with outpatient follow up.

myasthenia gravis, magnesium, seizure