Thyrotoxic periodic paralysis in a white woman. (Case Report).

A 24 year old white woman presented with sudden onset of flaccid quadriparesis and hypokalaemia. She was later found to be thyrotoxic. Paralysis resolved with potassium supplements, and after initiation of antithyroid medication she had no further episodes of hypokalaemic paralysis. To the best of the authors' knowledge, and after a Medline search, thyrotoxic periodic paralysis has not been described previously in a white woman.

A 24 year old white woman of English ancestry presented with a sudden onset of flaccid quadriparesis. There was no history of recent strenuous physical exercise. She denied any symptoms of hyperthyroidism: there was no weight loss, palpitations, heat intolerance, irritability, diarrhoea, or menstrual disturbance. She had no significant past medical history and no family history of thyroid disease or muscle disease.

On examination, pulse rate was 100 beats/min, blood pressure 120/70 mm Hg, and there was reduced tone and absent reflexes in all four limbs. She had a mild tremor but no lid lag and no signs of thyroid eye disease. She had a moderate size goitre with a soft bruit.

Investigations showed a serum potassium of 2.1 mmol/l (3.7-5.0) with normal sodium, urea, and creatinine. Electrocardiography showed a sinus tachycardia. She was given intravenous and …