An Unusual Case of Acute Muscle Weakness

A previously healthy 35-year old man presented to hospital with acute leg weakness following an alcohol binge. On assessment, tachycardia, urinary retention and bilateral upper and lower limb proximal weakness with preserved peripheral power were noted. Biochemistry revealed marked hypokalaemia, which responded to intravenous replacement, and biochemical thyrotoxicosis, leading to the diagnosis of Thyrotoxic Periodic Paralysis (TPP). Anti-thyroid therapy and beta-blockers were commenced and his neurological symptomatology resolved as he became progressively euthyroid. TPP is a rare acquired subtype of hypokalaemic periodic paralysis, typically causing proximal muscle weakness associated with thyrotoxicosis. It is most common in young Asian males. Acute treatment requires cautious oral potassium supplementation, beta-blockade, and anti-thyroid therapy. TPP is prevented by maintaining euthyroidism; otherwise recurrence is likely.