RESUMO
Thyrotoxic periodic paralysis (TPP) is a rare complication of hyperthyroidism, often presents with limb muscle paralysis, hypokalemia with elevated-free T3, T4, and low thyroid-stimulating hormone (TSH). We herein reported an unusual presentation of TPP with acute hypercapnic respiratory failure. A 28-year-old female had complaints of nausea and vomiting. Laboratory investigations showed a serum potassium level of 1.2 mEq/L. Thyroid function test revealed the TSH level of 0.021 µlU/mL and free T4 at 2.01 ng/dL. She suddenly suffered from dyspnea and drowsiness. Acute hypercapnic respiratory failure with CO2 retention was found. Noninvasive ventilation was used. Rapid correction of hypokalemia and administration of propylthiouracil, propranolol, and 5% Lugol's solution were performed. After the normalization of potassium levels, the patient's respiratory pattern stabilized and noninvasive ventilator (NIV) use was discontinued. Respiratory failure is an unusual but lethal complication of TPP. Rapid correction of hypokalemia and temporarily NIV can successfully avoid endotracheal intubation for respiratory failure.