OBJECTIVES: Sporadic inclusion body myositis (s-IBM) is characterized by progressive muscle weakness and inclusion bodies on muscle biopsy and is the most common type of myopathy in patients over 50 years old. However, it is not only under-diagnosed but also frequently misdiagnosed as polymyositis hence treated with steroids. In the evaluation of progressive weakness in older males, S-IBM should be investigated. This case report and literature review is presented to explore these issues. A discussion on the clinical and laboratory manifestations and histopathological findings are also included.

REPORT OF THE CASE: A 42-year-old male presented with six-year history of a slowly progressive weakness seen as difficulty brushing his teeth, buttoning his shirt, tying his shoelaces, associated with progressive dysphagia. He undergone EMGNCV of all extremities and was given a provisional diagnosis of facioscapulohumeral dystrophy. He was treated with Prednisone 5 mg/tab, 2 tablets twice a week, which he took for 2 years but afforded no relief. The weakness progressed, and he eventually required assistance to walk. Pertinent on general physical examination was severe, diffuse, symmetric muscle atrophy. Neurologic examination was consistent with proximal muscle weakness. Diagnostics showed normal CPK and ESR. Muscle biopsy revealed rimmed vacuoles, mononuclear inflammatory infiltrates, tubulofilaments which suggests a diagnosis of sporadic inclusion body myositis.

CONCLUSION: Though s-IBM is the most common myopathy in patients over 50 years of age, its symptoms can start up to 20 years earlier. Hence in the evaluation of progressive weakness in adult males, s-IBM should be an important diagnostic consideration.