Background: The features of primary hyperparathyroidism (PHPT) in developing countries have rarely been examined. This study explored the clinical characteristics of PHPT in India with the hypothesis that this may improve understanding of the pathogenesis of the disease worldwide.
Methods: Consecutive patients with PHPT (24 women, five men) were examined prospectively before and after parathyroidectomy.
Results: All patients had osteitis fibrosa cystica with a median symptom duration of 2.5 (range 1-26) years. Single or multiple fragility fractures were present in 14 patients (eight were bedridden); 20 had brown tumours. Mean preoperative serum calcium was 3.1 mmol/l, while mean serum intact parathyroid hormone (iPTH) and total alkaline phosphatase (ALP) levels were 17-fold and 12-fold higher than normal respectively. Nine patients had overt renal damage, mainly nephrocalcinosis. Parathyroidectomy invariably resulted in severe hypocalcaemia, necessitating long-term vitamin D treatment. The mean parathyroid gland weight was 8.6 (range 2.0-36.6) g and features of carcinoma were found in four patients. Serum calcidiol level correlated inversely (P < 0.05) with serum iPTH and ALP, and parathyroid gland weight.
Conclusion: PHPT in Indians is a severe, symptomatic disorder with skeletal, muscular and renal manifestations at a young age. The presence of this severe variant of PHPT in vitamin D-sufficient Indians, and the lack of skeletal disease in other vitamin D-deficient populations, raises the possibility of additional pathogenetic factors.