Hypocalcemia complicating acute leukemia

Eighteen of 54 adults with acute leukemia developed severe hypocalcemia during a 20 month period. Hypocalcemia (mean lowest serum calcium 6.3 mg/100 ml with a range of 4.1 to 7.0 mg/100 ml) lasted 2-29 days and was symptomatic in all but one patient. Six patients were hypocalcemic at the time of death, 5 died within 1 week of hypocalcemia, and 2 had antibiotic-induced respiratory arrest. All patients had severe infections; 17 of 18 were with gram-negative organisms. No patient had severe azotemia, diarrhea, alkalosis, or hypoalbuminemia. Hypophosphatemia was seen in 14 patients, suggesting no hypoparathyroidism. The serum calcium of patients with acute leukemia should be measured frequently, especially when they have infection. Hypocalcemia is a sign of poor prognosis and should signal the need for careful observation of ventilation, caution in the use of aminoglycoside antibiotics, and vigorous attempts at calcium administration.