Stiff Person Syndrome Masquerading as Acute Coronary Syndrome.

Stiff person syndrome (SPS) is a rare neuroimmunological disorder characterized by severe progressive muscle stiffness in axial and lower extremity musculature with superimposed painful muscle spasms. Although chest pain is a common reason for SPS patients presenting to the emergency room, this disorder is overlooked and not part of the differential diagnosis of chest pain. Herein, we report on a middle age male presenting with classic symptoms of SPS; however, due to the rarity of this disease, he was initially thought to have acute coronary syndrome. Clinicians should consider the diagnosis of SPS in patients with fluctuating muscle spasms in the torso and/or extremities in the setting of repeated hospitalizations without subsequent symptom relief.