Muscle Weakness in a Patient with History of Poliomyelitis: A Differential Diagnosis for Post-polio Syndrome (PPS) and Dermatomyositis

ABSTRACT

Dermatomyositis (DM) is an idiopathic inflammatory myopathy, characterized by inflammation of the proximal skeletal muscles and typical skin manifestations, which results in symmetric muscle weakness. A 43-year-old man was presented with skin rash and left leg weakness, and he had a history of poliomyelitis. Initially, he was diagnosed as having post-polio syndrome (PPS) due to unilateral muscle weakness and a result of an the electromyography (EMG), which had shown patterns of PPS. After 4 months with conservative therapy for PPS, weakness of bilateral upper arms had developed and skin rashes on his entire body had aggravated and progressed. He was diagnosed as having dermatomyositis, based on elevated muscle enzyme levels, typical skin rashes, and typical EMG findings, which indicated muscle disease. When a patient with previous poliomyelitis has a newly developed muscle weakness or pain, we should consider various possible causes other than PPS.