Case of Thyrotoxic Periodic Paralysis Accompanied by Atrioventricular Block Associated with Hypokalemia and Hypophosphatemia

ABSTRACT

Thyrotoxic periodic paralysis (TPP) occurs in 2% of the asian patients with hyperthyroidism and is characterized by bilateral flaccid paralysis of the extremity, especially lower limbs. It is well-known that hypokalemia is usually accompanied by TPP. However, hypophosphatemia is usually mild and well neglected. Although paralysis is generally recovered without treatment, in some cases, patients with TPP may die due to cardiopulmonary complications, such as cardiac arrhythmia. Therefore, proper and rapid replacement of potassium is essential. But it should be acknowledged that replacement may cause a rebound. TPP is often unrecognized and over-treated in the emergency room due to its non-specific symptoms. This is why clinicians must be familiar with this disease and its diagnostic clues such as Echocardiography change and clinical features. This is a case report of a 29-year-old male presenting with TPP accompanied by hypokalemia, hypophosphatemia and second degree atrioventricular block, who showed rebound hyperkalemia and hyperphosphatemia after rapid replacement of electrolytes. EKG changed to the normal sinus rhythm in the end after the correction of the electrolytes.