ABSTRACT
BACKGROUND: Thyreotoxic hypokalaemic periodic paralysis (THPP) is a rare and potentially life-threatening syndrome. It principally affects men of East-Asian origin and has rarely been described in a white person. CASE DESCRIPTION: A 34-year-old Dutch man, suffering from Graves' disease, presented with weakness in his lower limbs. Laboratory investigation showed severe hypokalaemia (1.8 mmol/l) and increased creatinine kinase levels. An electrocardiogram showed atrial fibrillation with a prolonged QTc-interval. The patient was admitted, cardiac rhythm was monitored, and he received potassium supplements. Laboratory investigation of thyroid function showed thyrotoxicosis. The patient was treated with propranolol and thiamazol. At follow-up, thyroid function, potassium levels and muscle strength had normalized. CONCLUSION: Hypokalaemia due to thyrotoxicosis should be considered in cases of unexplained paralysis. The treatment of THPP consists of treating for hyperthyroidism plus propranolol. Since the hypokalaemia is self-limiting, potassium supplementation is only necessary in cases of rhythm disturbances or cardiac-conduction disturbances. Despite adequate treatment, there is a risk of recurrence. Regular monitoring is indicated until euthyroidism is achieved.
