Bone mineralization and bone mineral content in primary hyperparathyroidism

Elevated bone phosphorus/hydroxyproline ratio following jejunoileal bypass surgery

The degree of bone mineralization, estimated as the bone phosphorus/hydroxyproline ratio (P/Hypro), was studied in 33 patients who had undergone jejunoileal bypass surgery for massive obesity. Low values of bone P/Hypro are expected in osteomalacia. We found an elevated mean bone P/Hypro (p < 0.001) with the highest values in patients with the longest postoperative periods (rS = 0.65, p < 0.001). The study indicates that bypass surgery, in spite of vitamin D deficiency, is associated with an increased average degree of bone mineralization or a defect in bone collagen synthesis.

Bone composition and parathyroid function in chronic renal failure

The development of bone abnormalities has been studied in 24 patients with severe chronic renal failure. The glomerular filtration rate (GFR) was between 5 and 25 ml/min. The mean values of plasma calcium, degree of bone mineralization (P/Hypro) and bone mineral content (BMC) were subnormal, whereas the mean values of plasma phosphorus and serum parathyroid hormone (PTH) were elevated. Analysis of the data revealed that the various parameters became increasingly pathological with decreasing renal function. Serum PTH correlated inversely with both GFR and plasma calcium. The decrease in bone P/Hypro with decreasing renal function could be explained by an inverse correlation to serum PTH. Plasma alkaline phosphatase correlated inversely to both bone P/Hypro and BMC. The present study on individual patients with varying degrees of renal insufficiency shows that the development of secondary hyperparathyroidism correlates with a reduction in the degree of bone P/Hypro and suggests that significant bone changes appear when the GFR falls below 15 ml/min.

Primary hyperparathyroidism: changes in trabecular bone remodeling following surgical treatment--evaluated by histomorphometric methods

Iliac bone biopsies from 11 patients who underwent successful surgery for primary hyperparathyroidism were examined before and median 7 months after surgical treatment. Trabecular bone volume increased (p less than 0.05) and eroded (p less than 0.005) and osteoid covered surfaces decreased (p less than 0.005) in the postoperative period. Also, a decline in tetracycline labeled surfaces was noticed (p less than 0.02). Osteoid thickness, mineral appositional rate and mineralization lag time were unchanged. Bone formation rate at the level of the basic multicellular unit (BMU) was unaffected, but at the tissue level bone formation rate diminished (p less than 0.02). The surgical cure of primary hyperparathyroidism was found accompanied by a change in bone metabolism as the trabecular bone remodeling decreased from a high turnover to a low turnover state. The spongy bone mass increased after parathyroidectomy but the clinical significance of this finding was not clear.

Bone mineral changes in primary hyperparathyroidism

We studied 34 patients with primary hyperparathyroidism in order to assess their bone mineral status, to determine its relationship to biochemical parameters (serum calcium and parathyroid hormone) and surgical status, and to determine the relationship between peripheral cortical bone and spinal trabecular bone in this disease. These patients were studied with radiogrammetry of the metacarpals, Norland-Cameron photon absorptiometry of the radius, quantitative computed tomography (QCT) of the spine, industrial radiography of the hands, and conventional radiography of the thoracolumbar spine. We also calculated a spinal fracture index from thoracolumbar spine films. We found that the appendicular measurements correlated well together, but less well with spinal QCT. The spinal fracture index correlated best with QCT (r = -0.55), although significant dispersion was noted. We found that, in general, these hyperparathyroid patients had statistically significant decrements in bone mineral content in both the appendicular and the axial portions of the skeleton. However, the decrement in the appendicular skeleton did not correlate well with that in the axial skeleton. Therefore we conclude that it is necessary to measure both peripheral and central bone mineral content in order to reliably assess the skeletal demineralizing effects of primary hyperparathyroidism in an individual patient.

Bone mineral density and skeletal fractures in familial benign hypercalcemia (hypocalciuric hypercalcemia)

To determine whether familial benign hypercalcemia, or familial hypocalciuric hypercalcemia (FHH), has adverse effects on the skeleton, we measured bone mineral density (BMD) in 31 affected persons from 14 families (16 women and 15 men), ranging in age from 19 to 68 years. Forearm BMD was measured by single-photon absorptiometry, and spinal BMD was measured by dual-photon absorptiometry. In addition, we systematically queried 82 hypercalcemic and 52 normocalcemic family members about skeletal fractures. Both men and women with FHH had normal BMD (expressed as grams per square centimeter) in the lumbar spine, distal radius, and midradius. Osteoporotic-type fractures (vertebrae, hip, and distal radius) were virtually absent in both affected and unaffected family members. Detailed evaluation of larger numbers of of older affected persons may be necessary to resolve this issue definitively, but we conclude provisionally that FHH has no important adverse effects on skeletal health.

Asymptomatic hyperparathyroidism: an assessment of operative intervention

The incidental finding of hypercalcaemia during multi-channel screening was the initiating event in 33 (45 per cent) of 79 consecutive cases of surgically treated primary hyperparathyroidism. This subgroup was asymptomatic as defined. Although significant biochemical differences existed between symptomatic and asymptomatic cases, a range of metabolic indices of bone turnover fell postoperatively in almost all asymptomatic subjects, although initially abnormal in only 35 per cent. Achievement of normocalcaemia was significantly surgeon-dependent.

Primary hyperparathyroidism. Incidence, morbidity, and potential economic impact in a community

We examined the incidence and clinical and economic consequences of primary hyperparathyroidism in residents of Rochester, Minn, from 1965 through 1976; 90 cases were found. From January 1, 1965, to June 31, 1974, the average annual incidence was 7.8 +/- 1.2 (mean +/- S.D.) cases per 100,000 population. However, after the introduction of routine measurement of serum calcium, the average annual incidence rose to 51.1 +/- 9.6 cases per 100,000. Even after availability of routine measurement of serum calcium, the annual incidence of primary hyperparathyroidism among persons 39 years of age or younger remained below 10 cases per 100,000. However, the annual incidence increased sharply in persons 40 or more years of age, reaching 188 cases per 100,000 among women 60 years of age and over and 92 cases per 100,000 among men 60 and over. For the last 1.5 years of the study, the average annual age-adjusted incidence of primary hyperparathyroidism was 27.7 +/- 5.8 per 100,000. The frequency of urolithiasis fell from 51 to 4 per cent (P less than 0.001), and the proportion of cases without symptoms or complications of primary hyperparathyroidism rose from 18 to 51 per cent (P less than 0.005). The median charge in 1977 for diagnosis and treatment of primary hyperparathyroidism was $1700. (N Engl J Med 302:189-193, 1980).