Does bracing affect bone density in adolescent scoliosis?

STUDY DESIGN

This is a case-control, cross-sectional analysis of bone density.

OBJECTIVES

To determine if bracing during growth affects bone density in adolescent idiopathic scoliosis and whether the effect is local or systemic.

SUMMARY OF BACKGROUND DATA

Data concerning the effect of bracing on bone mass in adolescents with idiopathic scoliosis are nonexistent. We were concerned that bone mass loss resulting from long-term brace use may be permanent and may predispose to problems with osteoporosis.

METHODS

Healthy adolescent females (n = 85) with scoliosis measuring 20-45 degrees and treated either by brace or observation were studied. Dietary calcium, activity level, body mass index, and pubertal status were evaluated. Scoliosis was measured by Cobb angle. Bone mineral density at the hip and spine were measured by dual energy x-ray absorptiometry to differentiate local versus systemic effects of bracing. Lateral scans of the L3 vertebral body were used to minimize the influence of the pedicles, the effect of the scoliosis, and the interference of the ilium.

RESULTS

Mean age, height, and weight were similar between braced and observed groups. After adjusting for curve, Cobb angle, body mass index, activity, and diet, two-way analysis of covariance showed L3 and femoral bone mineral density was the same for braced and observed patients, and pubertal status affected spinal bone mineral density but had no effect on femoral bone mineral density. Pubertal status and body mass index accounted for 53% of the variation in spine bone mineral density and was not affected by brace use. Cobb angle, curve pattern, activity, and diet were not associated with bone mineral density.

CONCLUSION

Brace treatment does not adversely affect bone mass at the spine and hip in children with idiopathic scoliosis.

Metabolic bone disease in gastrointestinal, hepatobiliary, and pancreatic disorders and total parenteral nutrition

Privational vitamin D deficiency is assumed to be uncommon in the developed countries because of the routine fortification of foods with vitamin D. Malabsorption of vitamin D and calcium (especially in an environment of reduced sun exposure) therefore accounts for the majority of cases of metabolic bone disease seen in patients with various gastrointestinal disorders in the United States. Yet recognition of this often asymptomatic bone disease is unsatisfactory and frequently delayed for months or even years. This results in severe irreversible bone loss, putting patients at increased fracture risk for the remainders of their lives. As evident from the small number of published reports, it is obvious that little attention is given to understanding the pathogenesis and prevention of bone disease in patients with various gastrointestinal disorders. This review will summarize recent advances in the pathogenesis, prevention, and treatment of metabolic bone disease in patients with these disorders. We propose methods for identifying bone loss in such patients so that appropriate preventive measures can be instituted to avoid significant morbidity.

The management of hypercalcemia of malignancy

Hypercalcemia (HCM) occurs in 10-15% of all malignancies, predominantly in patients with solid tumors. This metabolic complication leads to significant morbidity and impairment of quality of life. Recent insights into the pathophysiology of HCM include an understanding of the role of parathyroid-hormone-related peptide and several cytokines secreted by tumors. The osteoclast plays a central role as the final common pathway through which these hormones and cytokines act to cause bone lysis. These findings have led to the development of new treatment strategies. Foremost among these has been the introduction of agents such as the newer bisphosphonates and gallium nitrate, which are potent inhibitors of osteoclast-mediated bone resorption. The clinician can now choose from an array of therapeutic approaches based on a consideration of the mechanisms of action, individual clinical circumstances, efficacy, toxicities and costs of available agents. In addition to their use in the management of HCM, non-toxic drugs that effectively inhibit osteoclast function, such as the bisphosphonates, are playing an emerging role in the palliative treatment of the more common clinical problems of painful lytic bone metastases and osteoporosis.

Drug-induced disorders of bone metabolism. Incidence, management and avoidance

Calcium homeostasis depends upon the interplay of intestinal calcium absorption, renal excretion and skeletal mobilisation of calcium, mediated through bone formation and resorption, which are closely coupled in the adult skeleton. Serum calcium is extremely important for maintenance of normal cellular functions and is regulated by the major calciotropic hormones, parathyroid hormone (PTH), 1,25-dihydroxy-vitamin D and calcitonin. Certain drugs can interfere with calcium metabolism by effects at different stages in calcium metabolism, and a knowledge of the mechanism of drug action is generally helpful in understanding the various resultant clinical skeletal syndromes. Corticosteroids, for example, have profound effects at multiple stages of calcium metabolism, resulting in decreased bone formation and enhanced bone resorption leading to accelerated osteoporosis. Drugs such as aluminium and anticonvulsants impair mineralisation, leading to osteomalacia. Other drugs, such as fluoride, are employed for their known effects on bone, but in excess dosage can be harmful by producing mineralisation defects. Management of these conditions will be discussed in this review.

Comparison of single- and dual-energy quantitative computed tomography for therapy control under antiosteoporotic treatment

Lumbar spine bone mineral density was determined in 50 female patients (mean age: 55.4 +/- 12.3 years), who were treated because of osteoporosis or osteopenia. Bone mineral density was assessed using single-energy QCT with 80 and 120 kV tube voltage and with dual-energy QCT. Compared to single-energy QCT, dual-energy QCT showed much higher variability of the bone density values obtained. Therefore we conclude that single energy QCT is a method that allows precise and reproducible determination of spinal bone mineral content under clinical conditions which cannot be further improved by the use of dual-energy QCT.

[The evolutionary effects of therapy on the skeletal lesions in beta-thalassemia]

Up to the mid-1960s, beta-thalassemia was treated with blood transfusions as frequent as needed to keep symptoms under control and to prevent transfusional hemosiderosis. In the following years, high transfusion regimens and iron chelation therapy with desferrioxamine were used. Because of these different treatment modalities, skeletal findings in thalassemia have markedly changed. In the past, thalassemic patients treated with a low transfusion regimen and without chelation therapy developed osteopenia--with widened medullary spaces, cortical thinning and trabecular atrophy--secondary to chronic expansion of red marrow, due to increased erythropoietin response to chronic anemic hypoxia. Typical radiographic patterns in the skull included widened diploic space, atrophic-especially outer--tables and, in some patients, the "hair-on-end" pattern. As for the face, obliteration of the paranasal sinuses and the typical "rodent facies" were observed. In the ribs, bulbous expansion of the posterior and anterior segments and the "rib within a rib" patterns were observed. As for the spine, coarse trabecular arrangement was seen. The "cobweb" pattern was seen in the pelvis and finally the lack of the normal concave outline was observed in the long bones. In the patients treated with high transfusion regimens and iron chelation therapy over the last 30 years, both skull anomalies and disfigurement are less frequent. The skull is almost normal, with the exception of osteopenia and thickened diploic space in the frontal bone only; the paranasal sinuses are usually not obliterated. The hands and rib are normal, just like long bones, pelvis, scapulae and vertebral bodies. Nevertheless, in some adequately treated patients new skeletal features have been recently observed in the long bones, which are similar to those occurring in rickets and/or scurvy, and in the vertebral bodies, resembling platyspondylia. These abnormal features might be caused by several factors--i.e., marrow expansion, transfusion regimens, direct/indirect effects of desferrioxamine, iron load, endocrine abnormalities, deficiency of some minerals and finally dysvitaminoses. Nevertheless, osteopenia remains the main negative factor of thalassemia.

Thyrotoxicosis and hungry bone syndrome--a cause of posttreatment hypocalcemia

We report a case of a 54 year old woman with a history of recurrent Graves' disease, treated previously by thyroidectomy and later by radioiodine, who subsequently presented with tetany. Laboratory results revealed a profound hypocalcemia (total calcium 1.00 mmol/L; ionized calcium 0.53 mmol/L) and hyperphosphatemia (2.66 mmol/L) with low levels of parathyroid hormone. Although the patient's symptoms resolved after 5 days of treatment, hypocalcemia and elevated serum levels of bone-specific alkaline phosphatase (ALP, EC 3.1.3.1) activity and skeletal muscle isoenzyme (CK-MM) creatine kinase (EC 2.7.3.2) activity persisted to her discharge, 3 weeks later. Attention is drawn to the recognition and management of recalcification tetany due to the "Hungry (for calcium) Bone Syndrome," a biochemical and hormonal disturbance of calcium homeostasis and bone metabolism in the posttherapy thyrotoxic patient with hypoparathyroidism. This condition can be monitored by the use of calcium profile investigations, including bone-specific ALP, in addition to routine laboratory tests of thyroid function.

Management of osteopenia of liver disease with special emphasis on primary biliary cirrhosis

Bone disease occurring in the setting of chronic liver disease is being recognized increasingly often. The osteopenia may be an important cause of morbidity in these patients, particularly as effective treatments become available for the liver diseases and especially if these treatments actually worsen the coexistent bone disease. Although no specific treatments are of proven benefit for the bone disease in most instances, adequate exercise and calcium intake as well as vitamin D supplementation when deficiencies are present are recommended for all patients. Information is lacking about specific treatment for patients with PSC, hemochromatosis, and alcoholic liver disease. For patients with PBC, other than the above general measures, preliminary information suggests that supplemental estrogens in postmenopausal women and the use of calcitonin may offer promise; both measures are deserving of further study in this group of patients.

The medical care of iguanas and other common pet lizards

The majority of health problems in captive lizards result from improper diets, caging, and environmental conditions. This article discusses recommended husbandry and management techniques. A clinical approach to evaluating the health status of lizards, including assessing patient history, physical examination, clinical pathology, anesthesia, and surgery, is reviewed. Common health maladies of captive lizards are discussed, and rapid diagnosis and treatment are emphasized.

[Vitamin D prophylaxis in childhood]

The past 10 years have seen a return of rickets. Clinical and/or biochemical signs of vitamin D deficiency are still found in some children and adolescents, mainly during the winter. Sunlight exposure is able to prevent vitamin D deficiency and rickets but the dramatic influence of changes in solar ultraviolet-B radiation on cutaneous vitamin D3 synthesis, related to latitude and season effects, suggest that a vitamin D supplementation may be advisable. Moreover, human milk and common foods contain low quantities of vitamin D. So, we recommend routinely 400 IU of supplementary vitamin D per day in all infants. The vitamin D requirements in low-birth-weight infants are higher than at term infants; it is recommended the use of 1000-1600 IU per day in the first months of life. Intermittent high-dose of vitamin D and vitamin D metabolites are not advisable for prophylaxis of rickets.

The effect of low-frequency electrical fields on osteogenesis

An in vivo animal model of disuse osteopenia was used to determine the osteogenic potential of specific components of electrical fields. The ability of a complex pulsed electrical field to inhibit loss of bone was compared with the remodeling response generated by extremely low-power, low-frequency (fifteen, seventy-five, and 150-hertz) sinusoidal electrical fields. The left ulnae of thirty adult male turkeys were functionally isolated by creation of distal and proximal epiphyseal osteotomies and then were exposed, for one hour each day, to an electrical field that had been induced exogenously by means of magnetic induction. After a fifty-six-day protocol, the remodeling response was quantified by a comparison of the cross-sectional area of the mid-part of the diaphysis of the functionally isolated ulna with that of the intact contralateral ulna. Disuse resulted in a 13 per cent mean loss of osseous tissue, which was not significantly different than the 10 per cent loss that was caused by disuse treated with inactive coils. Exposure to the pulsed electrical fields prevented this osteopenia and stimulated a 10 per cent mean increase in the bone area. The osteogenic influence of the sinusoidal electrical fields was strongly dependent on the frequency; the 150, seventy-five, and fifteen-hertz sinusoidal fields, respectively, generated a -3 per cent, + 5 per cent, and + 20 per cent mean change in the bone area. These results suggest a tissue sensitivity that is specific to very low-frequency sinusoidal electrical fields, and they imply that the induced electrical fields need not have complex waveforms to be osteogenic. Since the frequency and intensity range of the sinusoidal fields producing the greatest osteogenic response are similar to the levels produced intrinsically by normal functional activity, these results support the hypothesis that electricity plays a role in the retention of the normal remodeling balance within mature bone.

Musculoskeletal complications after renal transplantation: pathogenesis and treatment

Renal transplantation is associated with several abnormalities of function and structure of the musculoskeletal system. Some of these skeletal problems result from incomplete resolution of abnormalities of bone and mineral metabolism present at the time of transplantation. In this regard, persistent hyperparathyroidism, diabetes mellitus type 1, and accumulation of beta 2-microglobulin may lead to residual skeletal effects despite excellent function of the allograft. Persistent hyperparathyroidism may accelerate bone loss and increase the risk for osteonecrosis, as well as cause hypercalcemia and hypophosphatemia; some patients with severe hyperparathyroidism require parathyroid surgery. Osteonecrosis is the most debilitating skeletal complication after transplantation and frequently requires surgical therapy. Although osteomalacia associated with aluminum overload generally resolves after transplantation, bone complications due to dialysis amyloidosis and diabetes mellitus type 1 often fail to improve. Alternatively, skeletal abnormalities can be acquired after transplantation. Most of the new derangements of bone and mineral metabolism are due to the immunosuppressive medications. Toxic effects of glucocorticoids on bone contribute to the pathogenesis of osteonecrosis, increase the risk for fractures by decreasing cancellous bone mass and synthesis of bone matrix, and dampen the linear growth response in pediatric recipients. Whether cyclosporine independently causes appreciable toxic effects on bone metabolism is not yet clear, but use of this drug increases the prevalence of gout and dental problems. Osteonecrosis, osteopenia, and short stature remain important skeletal complications in recipients of renal allografts. Therapeutic efforts should be directed toward alleviating pretransplant bone disease and attenuating bone loss after transplantation.

A useful technique for measurement of back strength in osteoporotic and elderly patients

Improvement of back extensor strength (BES) can be used as a therapeutic method for patients with chronic back pain and osteoporosis. The method of evaluation must be reliable and accurate without compromising the condition of the patient. We report the development of a back isometric dynamometer (BID-2000) designed specifically by two of us to address these concerns in elderly patients with osteopenia or osteoporosis. As the demographics of the general population change, increasing numbers of patients will need the type of monitoring that the BID-2000 provides. Aging has been shown to cause a reduction in the number of functional muscle motor units. To examine this effect on BES, we tested 50 normal, healthy women who were 30 to 79 years old. Proper testing of BES in patients with fragile vertebrae should include isometric measurement in the prone position, maneuverability of the device to allow comfortable positioning of the patient, and simplicity of technique to minimize repetitious performance of maximal contraction. The BID-2000 incorporates each of these features and also provides meaningful results inexpensively. The device offers a safe, reliable (coefficient of variation = 2.33%), and valid (P = 0.001) method of evaluation. The results of our study demonstrated moderate, steady reduction of BES with increasing age and with each successive decade.

Disorders of calcium and phosphorus homeostasis

Calcium and phosphorus are, respectively, the fifth and sixth most abundant elements in the body; both play vital roles in a multitude of physiologic systems. Because the great bulk of these elements is found in the skeleton, a large part of the discussion of calcium and phosphorus metabolism focuses on skeletal disorders, the impact of which falls heavily on young children. This article reviews the physiology of calcium and phosphorus, the skeletal and systemic consequences of disorders of vitamin D nutrition and metabolism, and the metabolic bone disease of prematurity.

[Diabetic osteopathies. 6. Treatment and its pitfalls]

The basic prerequisite of treatment of diabetic osteopenias is perfect metabolic compensation of diabetes. Insulin administration is an advantage in this respect, as it enhances calcium absorption from the gut and reduces its urinary excretion. Conversely, oral antidiabetics interfere in a negative way with vitamin D metabolism and thus also calcium metabolism and mineralization of bone. The combination of calcium, small doses of vitamin D, NaF and exercise used in the treatment of diabetic osteoporoses leads in general to a significant rise of the calcium serum level, an insignificant rise of the phosphorus level and it reduces alkaline phosphatase activity. A certain disadvantage is the elevated urinary calcium excretion. The main drug in diabetic osteomalacia are usually large doses of vitamin D. The rise of the serum calcium level improves the metabolic compensation of diabetes in a linear fashion. Thiazide diuretics used to reduce excessive calciuria cause slight deterioration of the glucose tolerance but the compensation does not cause major difficulties.

Heritable metabolic and dysplastic bone diseases

Endocrinologists may be challenged not only by the great diversity of rare heritable metabolic bone diseases, but also by an unusual array of genetically transmitted skeletal dysplasias. The striking impact that many such skeletal dysplasias have on bone leads physicians naturally to question whether there is a metabolic component that might respond to mineral or hormonal therapy. Indeed, overt derangements in mineral or hormonal therapy. Indeed, overt derangements in mineral homeostasis occur, and a few do respond to medical treatment. Accordingly, some skeletal dysplasias do "bridge the gap" with the disorders that are traditionally regarded as metabolic in origin. The skills of the endocrinologist may be called on for either group of patients.

The relationship of swimming exercise to bone mass in men and women

Exercise appears to be capable of exerting a positive effect on bone mass, but how exercise can be used to best advantage in the prevention and therapy of osteopenia is unclear. Weight-bearing activity has been commonly considered to be essential for the beneficial effects of exercise on the skeleton, and, therefore, swimming has been considered valueless in the maintenance of bone mass. To examine this issue we measured radial and vertebral bone mineral density in a group of subjects aged 40 to 85 years who had been swimming regularly for at least 3 years as well as in a similar group of nonexercising control subjects. The swimmers engaged in no other forms of regular exercise, and no subject had other conditions known to affect bone or mineral metabolism. Dietary calcium and protein intakes were similar in the two groups. At both radial (0.84 +/- 0.08 vs 0.81 +/- 0.09 g/cm2) and vertebral (123 +/- 27 vs 108 +/- 31 mg/cm3) sites the male swimmers had significantly greater bone mineral density than did the nonexercisers. In women, however, no relationship of swimming to bone mineral density could be identified. These results suggest that swimming exercise may be beneficial in the prevention or therapy of osteopenia and that its usefulness in this regard should be further investigated.

[Osteopenia in premature children: an emerging problem]

Osteopenia of preterm newborns is a condition of undermineralization which arises during the first years of life in very low birth-weight infants. The pathogenesis of disease is multifactorial, even if its main mechanism is the inadequate mineral intake (overall the inadequate phosphorus intake). A wide spectrum of signs and symptoms may be observed ranging from overt rickets to asymptomatic conditions. Diagnosis is usually based on either photon or biochemical findings (hypophosphoremia, hyper calciuria, hypophosphaturia). There is not agreement about the prevention and the treatment and about the benefit of any form of mineral supplementation. The aim of our study is a review of the recent studies concerning the osteopenia of prematurity to focus this new problem.

Importance of gonadal steroids to bone mass in men with hyperprolactinemic hypogonadism

STUDY OBJECTIVE

To determine the effects of alteration of gonadal steroids on bone mass in men with hyperprolactinemic hypogonadism.

DESIGN

Prospective survey of patients for a median period of 33 months.

SETTING

Neuroendocrine clinical center of a referral-based university medical center.

INTERVENTIONS

Reversal of hyperprolactinemia by bromocriptine therapy, transsphenoidal surgery, or radiation therapy, alone or in combination.

PATIENTS

Consecutive sample of 20 male patients with prolactin-secreting pituitary tumors.

MEASUREMENTS AND MAIN RESULTS

In patients who had a reversal of hyperprolactinemia and a restoration of gonadal function, a significant increase in bone density of the radial shaft was noted (mean +/- SE, 0.77 +/- 0.03 to 0.84 +/- 0.03 g/cm2; P less than or equal to 0.05). These patients also had a minimal change in the density of vertebral bone (109 +/- 9 to 115 +/- 10 mg of potassium phosphate, dibasic/cm3). Patients who remained hypogonadal despite the reversal of hyperprolactinemia had no change in radial (0.76 +/- 0.03 to 0.76 +/- 0.04 g/cm2) or vertebral bone density (105 +/- 10 to 103 +/- 9 mg of potassium phosphate, dibasic/cm3). There was a positive correlation between the change in testosterone level and the change in radial (r = 0.67, P less than or equal to 0.003) or vertebral bone density (r = 0.70, P less than or equal to 0.003).

CONCLUSIONS

The reversal of hypogonadism, independent of the prolactin concentration, is associated with an improvement in bone mass. Our findings emphasize the importance of gonadal steroids in maintaining skeletal integrity in men.

Osteopenia

Osteopenia in the elderly is responsible for 1.3 million fractures per year in the United States. The acute care costs associated with this disorder are between $6 and $10 billion dollars annually. Although much has been learned over the last few years of the factors that predispose patients to osteoporosis and how these factors may be avoided, the precise pathophysiologic mechanisms for bone loss remain obscure. Significant technological advances have been made in the 1980s in the development of noninvasive methods for measuring bone mineral density that give indirect assessments of bone mass. However, these methods are very controversial, are not suitable for mass screening for detecting subjects potentially at risk, and have a limited place in routine clinical care. Osteoporosis is characterized by thinning and fragmentation of trabecular bone, which is probably irreversible when it is far advanced. The most reasonable therapeutic approach may be prevention, which can be achieved in many patients by estrogen therapy in the perimenopausal years and insuring an adequate dietary calcium intake, particularly in adolescents and in the elderly. Physical activity throughout life is also likely to be important in maintaining adequate bone mass. It is important to differentiate osteoporosis from other causes of osteopenia, for example, osteomalacia, primary hyperparathyroidism, and malignant diseases such as myeloma, since these bone diseases have a different natural history, pathophysiology, and treatment.

Metabolic bone disease in alcoholic cirrhosis: a comparison of the effect of vitamin D2, 25-hydroxyvitamin D, or supportive treatment

In a study of 56 alcoholics with liver cirrhosis, 18 (32%) had decreased bone density and low levels of serum 25-hydroxyvitamin D (25-OH-D) (less than 20 ng per ml). To compare the efficacy of vitamin D2 and 25-OH-D treatment in correcting the metabolic bone disease in alcoholic cirrhosis, the 18 patients were randomized in the following manner, in groups of six patients each: Group 1, control (received no supplemental vitamin D treatment); Group 2, given vitamin D2 (50,000 IU p.o.) two to three times weekly, and Group 3, treated with 25-OH-D (20 to 50 mg p.o.) daily as required to attain normal serum 25-OH-D levels. The study period lasted 6 to 12 months (mean, 10.7 months). Initial histomorphometric study of transiliac bone biopsy with double tetracycline labeling in nine patients in whom biopsy was feasible showed only osteoporosis without evidence of osteomalacia. By the end of the study, serum 25-OH-D levels in the control group (Group 1) raised slightly while showing marked improvement in Groups 2 and 3. Bone density results remained unchanged in control patients but demonstrated a significant increase in both treatment groups. Vitamin D2 and 25-OH-D were equally effective in increasing bone density measurements. Posttreatment biopsies were performed in three patients of Group 2 and two patients of Group 3. While the histomorphometric results in Group 3 were not conclusive, in Group 2 improvement in static measures of bone remodeling was noted. Osteoporosis is the usual form of bone disease in alcoholic cirrhosis and a response to either vitamin D2 or 25-OH-D treatment is suggested.