Rickets of prematurity: a case report

A case report is given, and an attempt made to summarize our knowledge about this disorder. An extremely premature infant (birth weight 750 grammes) developed progressive rickets resulting in fractures despite phosphate, calcium and calciferol (vitamin D) supplementation. The patient had mild respiratory distress syndrome but later developed broncopulmonary dysplasia. Initial biochemical evidence of rickets occurred by the 6th week of post-natal life (or 31 weeks post-conceptional age). Although the serum levels of vitamin D or 1-alphahydroxy vitamin D were not determined, it is assumed that the levels of the active metabolite was probably low since clinical, biochemical and radiologic cure of the rickets occurred following its usage.

Can vitamin D deficiency produce an unusual pain syndrome?

An unusual pain occurred in five patients in the presence of compromised vitamin D status and resolved 5 to 7 days after supplementation with vitamin D in the form of ergocalciferol. The pain had a hyperesthetic quality and did not respond to the use of analgesics, including opiate derivatives. Treatment with therapeutic levels of a tricyclic antidepressant did not bring relief of symptoms. In one case, months after treatment and subsequent improvement of vitamin D status and pain, the vitamin D status again declined and the pain recurred. The pain again resolved with vitamin D replacement and improvement of levels. There may be a pain syndrome associated with vitamin D depletion that appears as hyperesthesia worsened by light, superficial pressure or even small increments of movement. This pain restricts mobility and function and may lead to further complications, such as pressure sores.

[Bone metabolic disorders due to antiepileptic drugs and the therapeutic effect of vitamin D2]

Bone mineral content(BMC), serum calcium, phosphorus and AKP were measured in 64 epileptic patients on long-term treatment with antiepileptics and in 14 epileptic patients not taking antiepileptics. All these indices were also measured in a group of healthy controls. In the epileptic patients taking antiepileptics BMC was significantly lower than that in the control group. Serum calcium and phosphorus were also lower than normal, while AKP was elevated. In the epileptic patients not taking antiepileptics BMC was not significantly different from that in the control group. Serum calcium, phosphorus and AKP were all normal. After 3 months of treatment with vitamin D2, BMC and serum calcium level returned to normal, but AKP was still significantly lowered.

Marrow space star volume in the iliac crest decreases in osteoporotic patients after continuous treatment with fluoride, calcium, and vitamin D2 for five years

Iliac crest biopsies in osteoporotic patients were obtained before and after five years of continuous treatment with sodium fluoride (40-60 mg/d), vitamin D2 (18,000 IE/d), and calcium phosphate (45 mmol/d). Star volume of marrow space and trabeculae, mean trabecular thickness, and fractional amount of trabecular bone were estimated on so-called vertical sections before and after treatment. Results showed a significant decrease in marrow space star volume after five years of treatment (35 mm3 versus 19 mm3) (2p less than 0.02). No significant changes were observed in trabecular star volume (0.149 mm3 versus 0.104 mm3) (2p greater than 0.50) or mean trabecular thickness (85 microns versus 79 microns, 2p greater than 0.30). A slight but insignificant increase in the fractional amount of trabecular bone was found (9.7% versus 10.4%, 2p greater than 0.50). A rather close inverse correlation was obtained, however, between individual changes in trabecular bone volume fraction and marrow space star volume (r = -0.72, 2p = 0.011). The findings suggest that the large marrow "cavities" had been split into two or more "cavities" by some newly generated trabecular structures leading to increased trabecular connectivity. The strength of trabecular bone may be increased due to this beneficial effect of fluoride on trabecular bone structure.

A sensitive radioimmunoassay using a monoclonal antibody that is equipotent for ercalcitriol and calcitriol (1,25-dihydroxy vitamin D2 and D3)

A monoclonal antibody has been used in a sensitive radioimmunoassay that measures 1,25-dihydroxyvitamin D2 (ercalcitriol) and 1,25-dihydroxyvitamin D3 (calcitriol) with equal potency. This important characteristic has not been reported for any other radioimmunoassay for 1,25-dihydroxyvitamin D. The two forms can be assayed in human serum together or individually after HPLC separation. Sample preparation entails acetonitrile extraction followed by C18-Sep-pak chromatography and HPLC. The assay measures 98% of added analyte, and achieves inter- and intra-assay coefficients of variation of 10.7% at 34 pg/ml and 7.8% at 81 pg/ml respectively. The limit of detection is 1.25 pg/tube and 50% displacement of bound ligand is achieved at 14 pg/tube. The reference interval is 20-50 pg/ml, mean 35. The correlation between results from the monoclonal radioimmunoassay and an established polyclonal antibody method was r = 0.98, slope 0.99. The assay has particular application in patients treated with vitamin D2 since 1,25-dihydroxyvitamin D2 can now be measured accurately in the presence of 1,25-dihydroxyvitamin D3.

[Prevention of hypocalcemia in low-birth-weight newborn infants: a comparative clinical study on the efficacy of ergocalciferol (Vit. D2) and calcifediol (Vit. 25(OH)D3)]

During the first week of life, 400 IU per day of 25(OH)D3 were given to 126 preterm and 112 full-term, small for date newborn infants, while 1000 UI per day of Vitamin D2 were given to 18 preterm and 27 full-term, small for date newborn infants, in order to compare their effectiveness for the prevention of neonatal hypocalcemia. 67 preterm and 67 full-term newborns were included in the control group. The incidence of late hypocalcemia was reduced from 16.4% to 0 in full-term babies and from 6% to 2.4% in preterm babies by the 25(OH)D3 but not by Vit. D2 administration. The incidence of early hypocalcemia was not modified at all. The Authors suggest 25(OH)D3 administration to prevent the late hypocalcemia and, together with calcium support, to treat the early hypocalcemia in the low birth weight newborn.

Linear growth in patients with hypophosphatemic vitamin D-resistant rickets: influence of treatment regimen and parental height

The effects of different treatment regimens and the influence of parental height on the statural growth of 40 patients with hereditary vitamin D-resistant hypophosphatemic rickets were investigated. Three treatment regimens, each with oral phosphate, were used: vitamin D (0.5 to 2 mg/day), calcidiol (50 to 200 micrograms/day), and 1 alpha-hydroxyvitamin D3 (1 to 3 micrograms/day). Mean duration of follow-up was 9.5 +/- 5.1 years. The results show that (1) there was no acceleration of growth before puberty for the majority of children treated with vitamin D (12/16) or calcidiol (13/15), whereas 1 alpha-hydroxyvitamin D3 promoted catch-up growth in 10 of 16 patients; (2) height gain during puberty was normal, irrespective of the treatment; (3) most vitamin D-treated male and female subjects and calcidiol-treated male subjects had short adult stature, but the majority (75%) of the 1 alpha-hydroxyvitamin D3-treated groups had normal stature; (4) parental stature had little influence on the adult height of male subjects, but that of affected girls was positively correlated (p less than 0.002) with mid-parental height. These results demonstrate that 1 alpha-hydroxyvitamin D3 is superior to vitamin D or calcidiol for improvement of stature of patients with hypophosphatemic vitamin D-resistant rickets, and indicate the importance of parental height in determining the adult height of affected girls.

Concentrations of vitamin D-binding protein and vitamin D metabolites in plasma of patients with liver cirrhosis

Plasma levels of vitamin D-binding protein (DBP) and vitamin D metabolites in patients with decompensated and compensated liver cirrhosis were assayed. Plasma levels of DBP in the decompensated group were significantly lower than those in the compensated group, but both were lower than the normal range. The plasma levels of 25-hydroxyvitamin D (25-OH-D) and 1 alpha,25-dihydroxyvitamin D [1,25(OH)2D] in the compensated group were within the respective normal ranges, whereas both values in the decompensated group were significantly lower than those in the compensated group. Most of 25-OH-D (higher than 96%) was confirmed to be circulated as a bound form with DBP in the plasma of not only the compensated but also the decompensated group. When vitamin D2 was given to the decompensated group, a significant increase of 1,25(OH)2D levels in the plasma could not be observed while 25-OH-D levels were increased. On the other hand, the administration of 1 alpha-hydroxyvitamin D3 (1 alpha-OH-D3) to the decompensated group caused a significant increase in the plasma levels of 1,25(OH)2D. Therefore, we suggest that the administration of 1 alpha-OH-D3 is useful for the treatment of bone disease induced by liver cirrhosis.

[Vitamin D deficiency and its correction in children with terminal stage of chronic kidney failure]

Content of vitamin D, evaluated by the level of 25(OH]D2 (calcidiol), was decreased in 68 patients with chronic kidney insufficiency, among which 16 patients required hemodialysis, 52 patients exhibited a terminal step of chronic kidney insufficiency and were treated with programme-assigned hemodialysis. Content of the vitamin was more distinctly decreased in the patients, kidney insufficiency of which developed simultaneously with congenital and hereditary kidney diseases. Phosphorus-calcium metabolism in the patients was corrected using both high doses of vitamin D2 (20,000 IU) and I alpha-hydroxycholecalciferol (oxidevite) combined with small doses of vitamin D2 (2,000 IU). The later procedure was more effective. After the treatment calcidiol was normalized within a month and maintained within a year at a level close to normal values. Blood calcium was normalized within 2 months, while normalization of parathormone and thyrocalcitonine occurred within a year. After treatment with vitamin D2 at a dose of 20,000 IU distinct hypercalcediolemia as observed in all the patients within 4 months. In 25% of the patients we noted hypercalcemia, which might lead to metastatic calcification.

Vitamin D metabolism in biliary atresia: intestinal absorptions of 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3

In children with biliary atresia, defective intestinal absorption of vitamin D and impaired hepatic uptake and 25-hydroxylation of vitamin D lead to a deficiency of vitamin D and rickets. We recently observed severe rickets in a 3-year-old boy with corrected biliary atresia resulting in jaundice, despite oral treatment with 1 alpha-hydroxyvitamin D3 (1 alpha-OHD3) or 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]. He had low 25-hydroxyvitamin D (25-OHD) and high 1,25-(OH)2D serum levels. Intramuscular vitamin D2 administration produced radiological and biochemical evidence of recovery. Oral 1,25-(OH)2D3 (0.1 microgram/kg) and 25-OHD3 (10 micrograms/kg) tolerance tests were done to assess the ability to absorb vitamin D and the effectiveness of using these drugs orally. Eleven children with corrected biliary atresia, aged 9 months to 7 years, were studied. In oral 1,25-(OH)2D3 tolerance tests, the increments above the baseline serum levels of 1,25-(OH)2D were 140.7 +/- 27.4 pg/ml in nonjaundiced patients (n = 5). In jaundiced patients (n = 3), 1,25-(OH)2D3 absorption in two patients with high basal 1,25-(OH)2D values was lower than that of nonjaundiced patients; however, the absorption in the third patient with a low basal value was similar to that of nonjaundiced patients. In oral 25-OHD3 tolerance tests, the mean increase of serum 25-OHD was 48.9 +/- 30.6 ng/ml in nonjaundiced patients (n = 5) and 23.7 +/- 9.5 ng/ml in jaundiced patients (n = 4), the peak serum 25-OHD levels being reached 6-12 h after 25-OHD3 loading.(ABSTRACT TRUNCATED AT 250 WORDS)

Verhoeff's query: is vitamin D effective against retinoblastoma?

In 1966, Verhoeff suggested that retinoblastomas might be sensitive to vitamin D because they sometimes undergo calcification and spontaneous regression. In recent years, the antineoplastic effect of vitamin D has been established in vitro and in vivo. This study presents evidence that vitamin D2 inhibits the growth of the human retinoblastoma cell line (Y-79) grown in athymic mice. In mice treated with ergocalciferol, the subcutaneous retinoblastomas were smaller and showed increased tumor necrosis and calcification. Unfortunately, the vitamin D caused significant toxic reactions. Further studies that reduce the toxicity of vitamin D will be needed before its use in children with retinoblastomas can be advocated. To our knowledge, this is the first demonstration of the activity of ergocalciferol against a tumor in vivo and it suggests that ergocalciferol or one of its derivatives may be an effective chemotherapeutic agent against retinoblastomas in humans.

Vitamin D-deficiency in the elderly: treatment with ergocalciferol and hydroxylated analogues of vitamin D3

The purpose of the present work was to study the effect of vitamin D and its metabolites in correcting hypovitaminosis D in the elderly. Thirty elderly people (mean age 78.4 years) participated in this study. They all had low serum levels of 25-hydroxyvitamin D (25-OH-D), of 24,25-dihydroxyvitamin D [24,25(OH)2D] and of 1,25-dihydroxyvitamin D [1,25(OH)2D]. These low levels did not increase in nine subjects after oral administration of vitamin D2 (3,000 IU/day for 12 weeks). However, administration of 1 alpha-hydroxyvitamin D3 (1 alpha-OH-D3) to 12 other subjects (0.5 micrograms/day for 8 weeks) led to a significant increase in the serum levels of 1,25(OH)2D. The other vitamin D metabolite levels remained unchanged. A significant increase in the levels of all three main vitamin D metabolites was obtained following administration of 25-hydroxyvitamin D3 (25-OH-D3) to a third group of nine subjects (25 micrograms/day for 1 week). These results suggest that vitamin D nutrition in elderly people insufficently exposed to the sun could be maintained by regular administration of 25-OH-D, whereas the administration of native vitamin D (ergocalciferol) in the doses used was inadequate for vitamin D nutrition.

Bone and mineral metabolism in adult celiac disease

Bone mineral density (125I photon absorptiometry) was lower in 20 untreated adult celiac patients than in sex- and age-matched controls (p less than 0.001), and plasma alkaline phosphatase, parathyroid hormone, urinary hydroxyproline/creatinine levels were higher than normal (p less than 0.05, less than 0.001, less than 0.05, respectively). Gluten-free diet was started, and the patients were divided randomly into two treatment groups, one which received oral 25-hydroxyvitamin D 50 micrograms/day and one which did not. After 12 months' treatment, bone turnover markers showed a decrease, which did not reach statistical significance, and bone mineral density did not show significant modifications compared with base line in either group. It was found that a gluten-free diet followed for 1 yr can prevent further bone loss, but no significant differences were detected between the two groups.

Primary hypoparathyroidism in the dog. Report of 15 cases and review of 13 previously reported cases

Fifteen dogs with primary hypoparathyroidism diagnosed at the University of California Veterinary Medical Teaching Hospital were compared with 13 previously reported cases. Age, sex, breed, and historical and physical findings were similar in both groups of dogs. Middle-aged females were affected primarily. A history of neurologic or neuromuscular disease was present in all 28 dogs, with 18 dogs having seizures. Posterior lenticular cataract formation secondary to hypocalcemia was suspected in six dogs. The most characteristic biochemical finding in all dogs was profound hypocalcemia (less than 6.5 mg/dl) and mild hyperphosphatemia. Serum magnesium concentrations were decreased in two dogs. Serum parathyroid hormone concentrations were consistent with the diagnosis of primary hypoparathyroidism in eight of nine dogs. Lymphocytic parathyroiditis was diagnosed in the 12 dogs from which tissue was submitted for histopathology. Successful management of the patient depended on frequent monitoring of the serum calcium concentration during initial and maintenance therapy.

Hypercalcemic hyperparathyroidism complicating oncogenic osteomalacia. Effect of successful tumor resection on mineral homeostasis

Described herein is a case of oncogenic osteomalacia that ran a course of at least 16 years before curative resection of a mixed mesenchymal tumor. Hypercalcemic hyperparathyroidism developed in the patient, and review of the literature indicated that this occurs in about 10 percent of reported cases. Changes in serum parathyroid hormone levels with and without phosphate supplement therapy and before and after tumor resection suggested that both the high intake of phosphate and the effect of the neoplasm on vitamin D bioactivation engendered the parathyroid overactivity. Despite marked hyperparathyroidism, serum 1,25-dihydroxyvitamin D levels were subnormal preoperatively but showed a sevenfold increase within 48 hours of tumor resection. Thereafter, a gradual increase in the maximal tubular reabsorption of phosphate occurred during several months. Biopsy of the iliac crest confirmed that tumor removal was followed by resolution of osteomalacia, but there was no accompanying increase in vertebral mineral density as assessed by quantitative computed tomography or in total-body bone mineral as measured with dual-photon absorptiometry. The findings presented are consistent with secretion by the tumor of a factor with a short half-life that is potent enough to inhibit renal 25-hydroxyvitamin D-1 alpha-hydroxylase despite hyperparathyroidism. The resulting subnormal circulating 1,25-dihydroxyvitamin D levels may have secondarily contributed to decreased renal tubular reabsorption of phosphate.

Calcium and vitamin D supplements: effects on calcium metabolism in elderly people

Calcium and vitamin D status were studied in 193 healthy elderly French people. Calcium intake was less than 500 mg/d in 62% of the patients and the vitamin D intake was less than 5 micrograms/d in all patients. They also exhibited reduced levels of serum calcium (SCa) and 25-hydroxyvitamin D (25-OHD) and high levels of parathyroid hormone (PTH) and alkaline phosphatase (SAP). The response to calcium (1000 mg/d) and ergocalciferol (20 micrograms/d) supplementation given for 6 mo was evaluated in 65 patients with 69 subjects taken as controls. The treatment induced a significant increase in SCa and in 25-OHD levels, and a subsequent decrease in PTH levels without modification of the mean calcitriol levels. The biochemical changes were more marked in long-stay hospital patients than in outpatients. All these changes were significantly different from those observed in the control group. Increasing the calcium and vitamin D intake reduces the biochemical signs of secondary hyperparathyroidism in elderly people.

Hyperparathyroidism and low serum osteocalcin despite vitamin D replacement in primary biliary cirrhosis

Thirty-six patients with primary biliary cirrhosis (PBC) receiving calcium and calciferol supplements (100,000 IU monthly by im injection) were investigated for their calcium, vitamin D, PTH, and osteocalcin status. The corrected plasma calcium concentrations in PBC patients were significantly greater than those in normal subjects. While the mean serum 25-hydroxycholecalciferol and 1,25-dihydroxyvitamin D concentrations in these patients were similar to those in normal subjects, the mean serum PTH concentration was significantly greater, and it was supranormal in 11 patients. Three patients had elevated corrected calcium concentrations; 1 of them had a concomitant increase in ionized calcium and a supranormal PTH level, and another had a high normal PTH. Ionized calcium concentrations were normal in the rest. Serum osteocalcin concentrations were significantly lower in the patients compared with those in normal subjects. These results indicate that PTH concentrations are frequently elevated in PBC patients despite adequate vitamin D supplementation and normal or even supranormal plasma calcium concentrations. Nonsuppression of PTH concentrations and autonomy of PTH secretion suggest that vitamin D deficiency and secondary hyperparathyroidism in such patients probably occur much earlier in the natural history of this disease than is currently realized. Persistent nonsuppressible hypersecretion of PTH probably contributes to the bone disease of primary biliary cirrhosis. The low osteocalcin concentrations probably reflect diminished osteoblastic activity, which may also contribute to osteopenia in these patients.