Muscle pseudohypertrophy as the presenting manifestation of autoimmune hypothyroidism: Hoffmann's syndrome

Hoffmann syndrome, a rare manifestation of hypothyroid myopathy in adults, is characterised by muscle weakness, stiffness and pseudohypertrophy. Here, we report the case of a middle-aged man who presented with progressive weakness in proximal muscles (in the form of difficulty in climbing stairs, rising from a seated position, combing hair and lifting objects) and leg swelling for 6 months. Physical examination revealed pseudohypertrophy of calf muscles with pronounced symmetric weakness in proximal upper and lower limbs. His levels of thyroid stimulating hormone and creatine kinase were significantly elevated. Electromyography was indicative of a myopathic disorder. MRI revealed symmetrical hyperintensity of bilateral gastrocnemius-soleus muscles. Following the initiation of thyroxine therapy, there was a marked improvement in signs and symptoms. Hypothyroidism should be considered as a potential cause in the differential diagnosis of individuals presenting with muscle weakness and hypertrophy.