Calcium homeostasis in untreated pulmonary tuberculosis. I--Basic study

This study has been done to evaluate serum calcium, phosphorus (P), magnesium, parathyroid hormone (PTH), calcitonin (CT), and cyclic adenosine monophosphate (cAMP) in recently diagnosed pulmonary tuberculous patient, (n = 61) and the results were compared with the healthy control group (n = 22). Twenty four hours urine was collected for estimation of these electrolytes as well as cAMP. Nephrogenous cAMP (NcAMP) was calculated. Serum Ca and PTH were significantly reduced in TB groups, but CT was elevated. Serum Mg, P and cAMP as well as urinary Ca and Mg in TB groups were similar to that of the control group. Urinary P, cAMP NcAMP were increased in patient groups compared with the control. The reduced serum Ca could be due to impaired intestinal absorption of Ca, or deficient intake as a result of anorexia, decreased plasma albumin, decreased active metabolites of vitamin D or elevated CT. The rise in serum CT in TB might be due to increased CT secreted from the bronchial K-cells. Increased NcAMP might be due to the associated increase in serum antidiuretic hormone (ADH). The elevated urinary P in TB could be attributed to tissue breakdown, decreased serum PTH or increased CT.