Conn's Syndrome, Subclinical Cushing's Syndrome and Thyrotoxicosis Presenting as Hypokalemic Periodic Paralysis: A Case Report - Case Report

Abstract
Thyrotoxicosis and primary hyperaldosteronism both cause hypokalemic periodic paralysis. Here we report a 51-year-old woman presenting with severe hypokalemia due to both thyrotoxicosis and primary hyperaldosteronism. At first presentation, she had a potassium level of 1.5 mEq/L and thyrotoxicosis due to a hot nodule, and was diagnosed as having thyrotoxic hypokalemic periodic paralysis. After treatment with propylthiouracil and potassium, she completely regained muscle strength. Nevertheless, a decrease in potassium level was observed again when the replacement of potassium was discontinued. The further diagnostic work-up of the patient, who had also history of hypertention, revealed primary hyperaldosteronism and subclinical Cushing's syndrome due to adrenal adenoma on the left side. Whether thyrotoxicosis contributed to the hypokalemic periodic paralysis in this patient is a matter of debate. Adrenal hyperfunction should be considered in all patients with hypertension and hypokalemia regardless of the presentation of the case.