Hypokalemia with hypercalcemia. Prevalence and significance in treatment.

Hypokalemia is a potentially life-threatening biochemical abnormality in patients with hypercalcemia. We studied a large group of patients with hypercalcemia to determine the prevalence of hypokalemia. One hundred three patients with normal renal function and no history of taking potassium-depleting drugs comprise the substance of this study. Thirty three of 103 patients (32%) were hypokalemic. A higher prevalence (52.3%) was found in patients with hypercalcemia associated with malignant disease than in those with primary hyperparathyroidism (16.9%). In addition, the degree and frequency of hypokalemia were greatest at the higher serum calcium levels. The presence of hypokalemia must be considered when treating severe hypercalcemia; otherwise, vigorous use of diuretics may result in profound hypokalemia and tachyrhythmias.