Levofloxacin-induced Myasthenic Crisis

Published:December 06, 2012DOI:
      An 18-year-old female patient presented to the Emergency Department (ED) with a month history of progressive generalized weakness. Her temperature was 36.2°C and the examination revealed only a mild bilateral ptosis. Blood chemistry, including creatine kinase, C-reactive protein, and a full blood count were normal, and a urinalysis showed mild bacteriuria with negative nitrites. A Neurology outpatient consultation was recommended, and levofloxacin 500 mg prescribed as antibiotic treatment. The patient was discharged with the diagnosis of urinary tract infection. At home, 5 min after taking the first dose of levofloxacin, the patient developed a rapidly progressive weakness with dropped head, bilateral ptosis, slurred speech, and dysphagia. It was Friday night. She was again admitted in the ED, where, at first, an intoxication or drug abuse was suspected. Within a few minutes the patient suffered respiratory arrest and was intubated. She was admitted to the intensive care unit, where she received immunoglobulin 2 g/kg for 5 days, and started on prednisone 1 mg/kg. She was extubated 5 days later and was asymptomatic. Brain computed tomography (CT) was normal. Chest CT scan did not show evidence of thymoma. A lumbar puncture showed normal cerebrospinal fluid. Antibodies against the acetylcholine receptor were 20 mg/dL, the maximum detected in our laboratory. The patient has since undergone a thymectomy, is taking azathioprine 150 mg, and she is asymptomatic.
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