Hypercalcemic hyperparathyroidism and hypophosphatemic osteomalacia complicating neurofibromatosis

Summary Neurofibromatosis is sometimes complicated by impaired renal tubular reabsorption of phosphate, hypophosphatemia, and osteomalacia. Hyperparathyroidism has also been reported in patients with neurofibromatosis. When hypercalcemia and elevated levels of parathyroid hormone are found in osteomalacia, however, it may be difficult to determine if the hyperparathyroidism was primary or tertiary. We describe a patient with neurofibromatosis, hypercalcemic hyperparathyroidism, hypophosphatemic osteomalacia, vitamin D deficiency, and clear-cell hyperplasia of all four parathyroid glands. Serial biomechanical, bone biopsy, and densitometric studies confirmed that treatment with ergocalciferol, calcium, and phosphate supplements significantly improved the osteomalacia but caused increased parathyroid overactivity. After subtotal parathyroidectomy, the parathyroid hormone concentration became normal and the bone mineral content increased at the spine and hip, but inappropriate phosphaturia persisted. The findings indicate that hyperparathyroidism, osteomalacia, and vitamin D deficiency adversely affect each other.     

Osteocyte ultrastructure in renal osteodystrophy

Summary The ultrastructure of the osteocyte has been studied in 80 needle biopsies from the iliac crest of uremic subjects with renal osteodystrophy.Different types of osteocytes were present in the osseous trabeculae. Those recognizable in completely uncalcified osteoid tissue looked like normal osteocytes, even though the matrix was not mineralized. Those present in hypomineralized areas showed enlarged and irregular lacunae when examined under the light microscope; under the electron microscope these osteolytic-like changes were not evident and were found to have been produced by defective calcification of the perilacunar matrix. Osteocytes placed in matrix whose mineralization was normal were often surrounded by a border of crystals protruding side-to-side from the bone matrix into the lacunar space. Other osteocytes were placed in unusually wide lacunae. They showed evidence of osteolytic activity, chiefly consisting of irregularity of the lacunar wall, presence of flocculent, granular and filamentous material in the pericellular space, and calcification of mitochondria. Degenerating and degenerate osteocytes were also recognizable.     

Endocrinology of bone mineralization: An update

Throughout the world, millions of people suffer from fragilizing osteopathies such as osteomalacia and osteoporosis. Osteomalacia is a rare disorder, corresponding to mineralization abnormalities in adult bone, as opposed to rickets in children. Renal phosphate loss and hypophosphatasia are the main causes of vitamin-resistant osteomalacia. Diagnosis is based on clinical history, phosphocalcic metabolism assessment and, if necessary, molecular characterization, and must be rapid in order to initiate the most appropriate treatment and consider new treatments such as burosumab if necessary. Osteoporosis is characterized by reduced bone mass and strength, which increases the risk of fragility fracture. Fracture-related burden is expected to increase over the coming decades linked to the aging of population and a treatment gap. In order to reduce this treatment gap, it is important to develop two strategies: improvement of screening and of treatment. Systematic screening using the FRAX® fracture risk assessment tool could be useful to increase anti-osteoporosis medical treatment and reduce fracture rates. The question of treatment sequencing in osteoporosis is another challenge, notably after denosumab cessation, complicated by a decrease in bone mineral density and increased risk of fracture. New treatments are also available, including romosozumab, a humanized monoclonal antibody, which promotes bone formation and inhibits bone resorption by inhibiting sclerostin. Romosozumab is approved in several countries, including France, for treating severe osteoporosis in postmenopausal women at high risk of fracture and free of cardiovascular comorbidity. Endocrinologists need to be aware of these fragilizing osteopathies in order to improve both diagnosis and treatment.     

Long-term Fracture Risk in Patients with Celiac Disease: A Population-Based Study in Olmsted County,Minnesota

Celiac disease is associated with decreased bone density, but there are conflicting data regarding fracture risk. We determined the fracture incidence relative to matched controls in a population-based cohort with celiac disease before and after diagnosis. Olmsted County residents with celiac disease (n = 83) diagnosed between 1950 and 2002 were compared with 166 gender and age matched controls. Fracture histories were ascertained from each subject’s medical records. Celiac disease is linked to an increased fracture risk before and after diagnosis. Before the index date, cases had a fracture rate twice that of controls (CI: 1.0–3.9, P = 0.045) and 2.5-fold greater after the index date (CI: 1.1–5.6, P = 0.026). Appendicular and axial fractures were 2.5 (CI: 0.9–6.5) and 3.2 times more likely (CI: 1.0–10.5) after the index date. These observations support a rationale for earlier detection of celiac disease, and active management of bone disease before bone effects have occurred, to reduce the persistent risk of fractures.     

9例骨软化症临床误诊分析

目的 通过骨软化症的误诊原因分析,提高临床对该病的诊治水平,使其能够被早期诊断与治疗.方法 采用病例回顾的方法,分析9例骨软化症的临床资料,包括一般资料、临床表现、实验室检查、影像检查、误诊情况及治疗转归等.结果 9例患者均被误诊为严重骨质疏松症,其中3例被误诊为强直性脊柱炎,2例被误诊为腰椎间盘突出症,3例被误诊为无菌性股骨头坏死,1例误诊为肿瘤骨转移.在明确诊断为骨软化症之前,治疗效果不佳.确诊后,按骨软化症采取相应治疗,病情显著改善.结论 骨软化症在临床上非常容易与以骨痛、身体活动受限、脆性骨折等为主要临床表现的骨质疏松症相混淆而误诊为骨质疏松症及其他疾病.临床对于以骨痛、脆性骨折、骨骼畸形、活动受限和肌无力为主要表现的就诊患者,应进行全面检查,可以鉴别诊断,减少误诊的发生.     

小剂量阿德福韦酯导致低血磷性骨软化症两例并文献总结

目的 分析小剂量阿德福韦酯（ADV）导致低血磷性骨软化症的临床特点、治疗及预后。方法 结合我院诊断的两例服用阿德福韦酯后发生低血磷性骨软化症患者资料和国内外文献,对该症的临床特点、治疗、预后和早期诊断进行总结。结果 服用小剂量阿德福韦酯治疗慢性乙型肝炎导致低血磷性骨软化症患者共12例,男9例,女3例,均来自亚洲人群,年龄在（22~74）岁,服用阿德福韦酯（18~64)个月发现低血磷,血磷波动在（0.37~0.79）mmol/L,血钙正常或偏低,血钾偏低,且均有不同程度的骨质疏松,予补充钙剂、骨化三醇、欧思美等治疗预后良好。结论 小剂量阿德福韦酯所致低血磷性骨软化症临床相对少见,容易漏诊,凡服用阿德福韦酯的患者,无论剂量大小,均应定期检查血肌酐、血钙、血磷及骨密度,以监测是否发生肾损害及低血磷性骨软化症,以期早期诊断,一旦各项指标异常应立即停药,同时可换用其他抗病毒药,如干扰素、恩替卡韦等。     

Osteomalacia of the mother —rickets of the newborn

During the last 4 years we observed four cases of neonatal rickets. The mothers of the infants suffered from osteomalacia for 1–3 years prior to its diagnosis shortly after the birth of their children. All four infants were born with craniotabes, and one infant had, in addition, a radial fracture. The diagnoses were confirmed by radiological and laboratory tests which revealed a rarefied bone structure, decreased serum 25-hydroxy-vitamin D and increased alkaline phosphatase levels in all patients. The disorder regressed under low-dose vitamin D₃ therapy. As osteomalacia seems to be predominant in oriental women living in Berlin, it is necessary to consider vitamin D deficiency when clinical symptoms of this disease arise and to treat these women at least during pregnancy.     

Basic and clinical evaluation of the measurement of bone resonant frequency

Summary A new computerized apparatus was constructed to measure the resonant frequency of human ulnain vivo with high sensitivity and reproducibility. Experimental studies using aluminum bar and dried human bone revealed the importance of the ulna being positioned parallel to the radius, approximately 90 degree flexion of the elbow joint, and minimal muscle activity in order to demonstrate maximum resonant frequency of ulna. Measurement of bone resonance in monkeysin vivo and after removal of the bonein vitro showed good agreement. Product of F (maximum resonant frequency in Hz) and L (ulnar length in cm), FL, indicating the speed of propagation of sound wave through the ulna, showed a significant positive correlation with bone mineral content/bone width (BM/BW) measured by Norland-Cameron apparatus and age-bound decline in both sexes. Patients with osteomalacia and primary hyperparathyroid bone disease tended to have higher FL values than expected from BM/BW. Two-dimensional display of FL and BM/BW thus appears to be useful in distinguishing osteoporosis from osteomalacia better than the use of BM/BW alone.     

The effect of growth retardation and of osteomalacia on the uptake of albumin by bone

Summary ¹²⁵I-labeled rat albumin injected intravenously into rats was taken up by growing bone. Some of this radioactive albumin could be removed from bone by washing with saline, the proportion so removed decreasing from 82.5% at 1 day to 7.4% at 8 days. Both the total radioactivity, and that remaining in bone after saline wash, were reduced when growth was slowed by alteration or restriction of the diet. Although the amount of¹²⁵I albumin in rachitic bone was reduced, autoradiography showed that radioactivity was present in rachitic osteoid. Immunoprecipitation using anti-rat-albumin serum showed that about half of the radioactivity released from normal bone by EDTA was still attached to albumin. These results suggest that albumin plays some part in the growth of bone.Part of this work was presented at a meeting of the Australian Physiological and Pharmacological Society in May 1974     

Vitamin D dependent rickets: Decreased sensitivity to 1,25-dihydroxyvitamin D

A patient with vitamin D dependent rickets with decreased sensitivity to 1,25-Dihydroxyvitamin D was observed. She suffered from bone pain of two years duration beginning at 12 years of age and was found to be suffering from hypocalcemia, secondary hyperparathyroidism and osteomalacia. Laboratory findings revealed normal serum 25-hydroxyvitamin D (27 ng/ml) and markedly elevated serum 1,25-dihydroxyvitamin D (131.9 pg/ml). The hypocalcemia was refractory in spite of administration of 25,000 units of vitamin D₂, but therapy with high doses of oral 1-hydroxyvitamin D₃ resulted in significant elevation of the serum calcium level. The clinical findings and course of the patient's disease were quite different from those of other patients with vitamin D dependent rickets reported by other authors.