Association of hypercalcemia, elevated calcitriol levels, and tuberculosison hemodialysis

Hypercalcemia is associated with numerous chronic granulomatous processes a nd chronic infections. Increased production of calcitriol by activated macr ophages has been shown to be the cause in most cases. In this article, we d escribe three cases of hypercalcemia associated with inappropriately elevat ed calcitriol levels and suppressed PTH in hemodialysis. In addition to con ventional techniques for tuberculosis diagnosis we used Ligase Chain Reacti on (LCR) to detect mycobacterial DNA in pleural effusion with acid-fast sta in and culture negativity. Antituberculous therapy was associated with a de crease in the levels of calcium, as well as in serum calcitriol concentrati ons, and a substantial increase in the levels of iPTH. The serum levels of 25(OH)D-3 remained unchanged. These findings suggested ectopic production o f calcitriol. The discussion reviews the previously reported cases of hyper calcemia and tuberculosis that occurred during hemodialysis, and concludes that ectopic production of calcitriol by tuberculous granulomas is extremel y unusual and its demonstration requires a high index of suspicion. Molecul ar techniques are a potentially useful approach for early and rapid diagnos is of tuberculous infection in dialysis patients.