Thyrotoxic Periodic Paralysis: An Unusual Cause of Quadriparesis.

Thyrotoxic periodic paralysis (TPP) is an uncommon disorder characterized by acute onset of hypokalemia (serum potassium level less than 3.5 mmol/L) and paralysis secondary to thyrotoxicosis. Patients can present with TPP as the first clinical manifestation of thyrotoxicosis. In patients presenting with acute episodes, the presence of hypokalemia and elevated levels of thyroid hormones with low thyroid-stimulating hormone levels (less than 0.35 µIU/mL) are important diagnostic clues. We report one case of TPP in which the acute onset of paralysis was the first clinical presentation of underlying thyrotoxicosis. After treatment with propranolol and carbimazole, the patient became symptom-free and euthyroid.