Emergency Department Management of a Myasthenia Gravis Patient with Community-Acquired Pneumonia: Does Initial Antibiotic Choice Lead to Cure or Crisis?

BACKGROUND: Myasthenic crisis is a rare, yet serious condition that carries a 3%-8% mortality rate. Although infection is a common cause of decompensation in myasthenia gravis, several antibiotics classes have also been associated with an exacerbation. Selecting antibiotics can be a daunting clinical task and, if chosen inappropriately, can carry significant deleterious consequences. Not only do clinicians have to focus on treating the underlying infection appropriately, but avoiding antibiotics that may potentiate a myasthenic crisis is also vital. CASE REPORT: An 85-year-old female with a history of myasthenia gravis presented to the emergency department (ED) with increasing generalized weakness and shortness of breath. Clinical work-up was consistent with a community-acquired pneumonia (CAP) diagnosis. Her medical history included a myasthenia gravis exacerbation shortly after receiving moxifloxacin for CAP. After reviewing the patient's allergies, as well as potential antibiotic triggers, the decision was made to treat with tigecycline. The patient responded well to tigecycline therapy and was deemed stable for discharge on day 4 of hospitalization. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Evaluation of the myasthenia gravis patient frequently originates in the ED. It is important for clinicians to be able to distinguish between an underlying illness and a myasthenic crisis. In the event of an infectious process causing clinical deterioration in a myasthenia patient, optimal antibiotic selection becomes paramount. This patient case highlights the addition of tigecycline to the armamentarium of therapies available to treat myasthenia gravis patients presenting to the emergency department with CAP.