Study of serum calcium level in active pulmonary tuberculosis

ABSTRACT

In a study of 227 patients with active pulmonary tuberculosis, hypercalcemia was found in 59 [26%]. It was detected in 46 patients and developed in 13 patients 4 to 6 weeks after the start of antituberculous chemotherapy. The mean [ +/- SD] serum calcium level in those was 2.78 [ +/- 0.137] mmol/L. The majority of cases [67.6%] had a mild rise in the calcium level that remained below 2.8% mmol/L but 30% had a level that ranged between 2.8 and 3 mmol/L. Only 2.4% had serum level higher than 3.0 mmol/L, which could explain the predominant absence of hypercalcemia-related symptoms. Hypercalcemia was more common in patients older than 50 years [P < 0.05], but this did not correlate with the extent of the tuberculosis shown on radiological evaluation. Spontaneous return to normocalcemia occurred in all 40 patients who underwent serial assessments of their serum calcium concentration, 6 to 8 weeks after the start of chemotherapy. Saudi Arabia is known to have a high prevalence of vitamin D deficiency, but none of our patients were immobilized or had received vitamin D supplements or multivitamins. This supports the view that vitamin D intake does not play a major role in inducing hypercalcemia in cases of active pulmonary tuberculosis, as has been suspected