Hypothyroidism simulating as polymyositis

Polymyositis-like syndrome in hypothyroidism is a rare condition characterised by proximal muscle weakness and elevated muscle enzymes. Patients with this condition can initially be misdiagnosed as having polymyositis due to similar characteristics ofbothdiseases; however a response to thyroxine is the main differentiating feature. This report highlights the case of a 30-year-old male who had severe myalgia and proximalmuscle weakness. In addition to raised creatinine phosphokinase (CPK) levels, his biochemical profile showedhypothyroidism. Initially thought tobe sufferingfrom polymyositis, improvement in both clinical and biochemical profilewith thyroxine led to the diagnosis of polymyositis-like syndrome associatedwith hypothyroidism.