CALCIUM-METABOLISM AND ITS REGULATING HORMONES IN PATIENTS WITH LEPROSY

Calcium metabolism was studied in 47 patients with borderline or lepro matous leprosy. Total and ionized calcium, phosphorus, creatinine, tot al alkaline phosphatase, parathyroid hormone (PTH), 25-hydroxy vitamin D [25(OH)D], and 1, 25-dihydroxy vitamin D [1, 25(OH)2D] were measure d in serum; calcium and total hydroxyproline were determined in urine. Total subperiosteal diameter and medullar cavity diameter were measur ed on an X-ray of the hand of all patients. Average values were within normal ranges for all of the biochemical determinations. Total serum calcium was moderately below the normal range in eight patients but io nized calcium levels were within the normal ranges in all of the patie nts. Four patients, all of them with lepromatous leprosy, had levels o f 1, 25(OH)2D higher than normal but none of them was hypercalcemic an d PTH levels were within normal range. Although all values were within the normal ranges, lepromatous leprosy patients had lower total calci um, higher alkaline phosphatase, and higher urinary hydroxyproline tha n borderline leprosy patients (9.1 +/- 0.4 vs 9.4 +/- 0.3 mg%, p < 0.0 01; 10.3 +/- 2.9 vs 7.4 +/- 2.3 King-Armstrong units, p < 0.02 and 27. 2 +/- 12 vs 19.4 +/- 5.6 mg/24 hr, p < 0.02, respectively). No differe nces were found between patients and controls in the average micrometr ic measurements of the second metacarpal bone but significant osteopen ia was found in 19% of the patients. The main finding of the present s tudy in a representative sample of leprosy patients is that the averag e total serum calcium was in the lowest limit of the normal range, but the ionized serum calcium was in the middle of the normal range. Some patients had levels of 1, 25(OD)2D higher than normal but in none of them was the serum calcium increased. Therefore, it is possible that c alcium homeostasis is normal in most patients with leprosy and only in exceptional patients would it be possible to find significant alterat ions.