Hoffmann syndrome; a rare form of hypothyroid myopathy

Hoffman syndrome is a rare clinical presentation characterized by the presence of proximal weakness and muscle pseudo-hypertrophy in a hypothyroid patient. 50-year-old male presented with gradual onset muscle stiffness and weakness involving both bilateral upper and lower limbs for 3-months duration. Examination revealed generalized hypertrophy of the muscles, mainly involving the Gastrocnemius with proximal muscle weakness and slow relaxing deep tendon reflexes. His Thyroid Stimulating Hormone and creatinine kinase were elevated. Anti-Thyroid peroxidase antibodies were positive. Electromyogram (EMG) and muscle biopsy was suggestive of a myopathic disorder and a diagnosis of Hoffmann syndrome was made. Complete resolution of weakness was observed following thyroxine therapy. Hoffmann syndrome is a rare, myopathic disorder seen in long standing, untreated hypothyroidism and it has a favourable response to thyroid hormone replacement in majority of patients.