Thyrotoxic periodic paralysis in Caucasian patients: a diagnostic challenge

Secondary hypokalemic periodic paralysis is rare. However, when it occurs, it is usually associated with Graves' disease and it is mostly diagnosed in Asiatic male patients. In this report, we analyze the diagnostic procedure in three cases of hypokalemic periodic paralysis associated with Graves' disease, diagnosed in three different emergency care units over the last 3 years. Three Caucasian men (26, 30, and 39 years of age) came to the emergency care unit for acute tetraparesia. One of them had suffered 15 stereotypical episodes of tetraparesia during the last 2 years. Goiter was present in each case. Kalemia was 1.8, 2.1, and 3 mmol/l, respectively. Triggering events such as considerable sugar intake and physical exercise were present in two cases. In all cases, low TSH levels, high FT4 levels, and anti-TSH receptor antibodies led to the diagnosis of Graves' disease. All patients were treated with potassium supplementation and neomercazole. Outcome was good with a follow-up of 6, 9, and 24 months, respectively. Emergency care practitioners should be aware of this diagnosis, which may affect Caucasian patients presenting with transient tetraparesia in a primary care unit.