RESUMEN
BACKGROUND: Thyrotoxic periodic paralysis (TPP) is a complication of hyperthyroidism. MATERIALS AND METHODS: We describe two patients with TPP. RESULTS: A 26-year-old man from Vietnam had weight loss, tachycardia, palpitations and heat intolerance for five months. Episodic leg and arm weakness developed three months after debut of symptoms. The second patient, a 23-year old woman from the Philippines, had had episodic leg weakness in the evenings after dinner for three weeks. Her attacks resolved spontaneously overnight. Physical examination of both patients revealed tachycardia and symmetrical proximal weakness involving both arms and legs. ECG and electrolyte analysis indicated a severe hypokalaemia; thyroid function tests showed hyperthyroidism. Both patients were diagnosed as having Graves' thyrotoxicosis and TPP. They were initially treated with propranolol and subsequently with carbimazole. The first patient had recurrence of thyrotoxicosis and paralysis after 16 months, whereas the second patient has remained symptom-free. INTERPRETATION: TPP is most common in Asian males, very few cases are reported in females. In Western countries TPP is rare, but with increasing immigration, TPP is likely to occur more frequently.