Summary

The diagnosis of acute autoimmune rheumatic disorders in sickle cell disease (SCD) can be challenging. Polymyositis is an inflammatory myopathy which, like SCD, may present with myalgia but is usually associated with proximal muscle weakness. We describe an adolescent boy presenting with limb pain, difficulty in mobilisation, with progressive loss of motor function and later bulbar weakness. Investigations showed massive elevation of creatine kinase, and MRI and muscle biopsy findings consistent with severe polymyositis. The patient was treated with corticosteroids, intravenous immunoglobulin and intensive rehabilitation therapy. He made a good recovery and was discharged on azathioprine and prednisolone. In the context of SCD, multisystem symptoms, unexplained muscle pain and weakness, unresponsive to conventional treatment in the presence of steady state haemoglobin, should alert the clinician to autoimmune phenomena. Key factors in making a diagnosis are an autoimmune screen and early discussion with a rheumatology expert.