Pre- and postoperative bone metabolism of primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a well-known indicator of severe bone loss. However, the recovery process of bone mineral density after surgery in PHPT patients is not sufficiently clear. We examined postoperative bone metabolism in 24 PHPT patients.

Subjects were 24 patients with PHPT upon whom we performed parathyroidectomy in the Department of Surgery II, Fukushima Medical University. Mean age was 54.2 years and the male-to-female ratio was 10:14; mean time of follow-up was 27.3 months. Patients were divided histopathologically into 16 adenomas and eight hyperplasias, and classified by heredity into seven familial (six, MEN 1; one, MEN 2) and 17 sporadic types. Bone mineral density was measured by dual energy X-ray absorptometry (DXA) and digital image processing (DIP). Age-matched values of these parameters were obtained. Serum bone metabolic parameters; ionized calcium (CaF), phosphorus, intact PTH (iPTH), c-PTH, ALP, osteocalcin (OC) and PTHrP were measured.

PHPT patient preoperative bone mineral densities were significantly lower than those of healthy controls. Those by DIP method were lower than those by DXA. High CaF, iPTH, OC and ALP levels were indicated before surgery, but all parameters immediately became normal. Longitudinal bone mineral density changes of asymptomatic cases increased more than those of patients with renal stone and/or ostitis fibrosa. In adenoma cases, tumor weights were significantly inversely, which correlated with preoperative DIP bone density measurements.

Preoperative PHPT patients showed decreased bone density; bone loss in symptomatic cases was especially prominent compared to asymptomatic cases. Most PHPT patients had not completed the BMD recovery after surgery, so even asymptomatic and mild PHPT patients should undergo parathyroidectomy to minimize irreversible bone loss.