Endocrine Abstracts

Background: Musculoskeletal symptoms are common but unrecognized symptoms of thyroid dysfunction. We present a case report of an elderly man presenting with acute paraparesis as the first manifestation of thyrotoxicosis.

Case report: A 73-year man presented with 1-week history of weakness in both legs and inability to mobilize or stand. Neurological examination revealed severe proximal muscle weakness (grade 0/5 power) of both lower limbs with reduced tendon reflexes and normal plantar response. He did not have cranial nerve, sensory, cerebellar signs or bladder and bowel involvement. He did not have the classical symptoms of thyrotoxicosis. There was no tachycardia, tremor, goiter or evidence of thyroid eye disease. Biochemical profile revealed elevated free T₃, 11.1 pmol/l (NR 3.6–6.4) and free T₄, 53.0 pmol/l (NR 8.0–22.0) with suppressed, TSH <0.05 mU/l (NR 0.30–6.0). Anti thyro-globulin antibodies were negative. Serum electrolytes were normal and creatinine kinase was mildly elevated. Ultrasound thyroid revealed enlarged, heterogeneous thyroid gland with mixed echo texture and hypervasularity. Thyroid uptake scan showed diffuse increase in uptake in both lobes, consistent with Graves’ disease. He was treated with Lugol’s iodine (for 7 days) and carbimazole. Muscle weakness improved dramatically and he was able to walk unaided in a week with complete resolution of myopathy. He was subsequently rendered bio-chemically euthyroid with radioiodine.

Conclusion: This case report highlights a rare manifestation of common endocrine condition. It emphasizes the importance of considering thyrotoxicosis as a cause of acute myopathy among elderly patients presenting without the classical thyrotoxic symptoms and signs.