Body growth in primary de Toni-Debré-Fanconi syndrome

Body growth in nine children with primary de Toni-Debré-Fanconi syndrome was followed from birth to adolescence or adult life. At the time of diagnosis, corresponding to the start of treatment, the median age was 2.3 (range 0.4-13.9) years and height standard deviation score (SDS) was always decreased (median -3.5, range -6.8 to -2.1). Despite continuous electrolyte and bicarbonate supplementation only four patients showed a slight improvement in growth. At the time of the last observation at the age of 17.2 (4.5-20.1) years median height was -4.7 (-5.9 to -1.8) SDS. The median difference between height at last observation and target height was -4.5 SDS. Final height (n = 5) ranged between -1.8 and -5.5 (median -4.3) SDS. The pubertal growth spurt was absent in two children. Metabolic acidosis was identified as a significant growth-retarding factor. Mean serial blood bicarbonate levels and height SDS at the last observation were correlated (r = -0.87, P < 0.01). No correlation was observed between last height SDS and the degree of hypokalemia, hypophosphatemia, or hypercalciuria. In conclusion, patients with primary de Toni-Debré-Fanconi-syndrome present severe growth failure at the time of diagnosis which persists into adult life. Supportive therapy is frequently unable to prevent further loss of relative height.

Acute recumbency and marginal phosphorus deficiency in dairy cattle

Because of a mixing error at a local feed mill, a diet marginally deficient in phosphorus, compared with recommendation from the National Research Council, was fed to a high-producing dairy herd for 5 months. Two mature cows in early lactation became recumbent. Serum phosphorus concentration in 1 cow was low (1.8 mg/dl), but was not measured in the other cow. Ten other high-producing, first-lactation cows in the herd developed severe lameness. Results of analysis of rib bone samples from the recumbent cows were consistent with changes associated with demineralization. Bone ash, calcium, phosphorus, and magnesium concentrations were lower than published ranges for healthy cattle. Serum calcium, phosphorus, and magnesium concentrations in 8 unaffected cows were normal. For 6 unaffected cows, mean serum hydroxyproline concentration was higher during the period that the phosphorus-deficient diet was fed than when an adequate diet was fed. Moderate (15%) restrictions in dietary phosphorus intake, compared with National Research Council recommendations, can possibly result in health problems in high-producing dairy cattle.

Antacid-induced osteomalacia

The case of a 49-year-old woman suffering from generalized skeletal pain and multiple fractures accompanied by severe hypophosphataemia and low urinary phosphorus excretion is reported. She had been taking large amounts of antacids containing aluminum hydroxide for many years. A diagnosis of antacid-induced osteomalacia was made. It was confirmed by biological work-up, radiographs and bone biopsy. A dramatic biological, osteodensitometric, and clinical improvement was achieved by withdrawal of antacids and phosphorus administration. The literature concerning this unusual condition has been reviewed.

Use of a phosphorus-enriched dialysate in a hypercatabolic renal failure patient receiving intensive hemodialysis therapy

An elderly man with end-stage renal disease required intensive hemodialysis therapy because of sepsis-induced hypercatabolism. We were able to prevent the occurrence of hypophosphatemia by using a phosphorus-enriched dialysate during hemodialysis treatments.

High incidence of hypophosphatemia in surgical intensive care patients: efficacy of phosphorus therapy on myocardial function

OBJECTIVE

To determine the incidence of hypophosphatemia in a surgical intensive care unit and to determine whether or not a phosphorus challenge causes a change in cardiac performance in hypophosphatemic patients.

DESIGN

Prospective clinical study and case reports.

SETTING

Surgical intensive care unit in an university hospital.

PATIENTS

A total of 208 consecutive patients admitted to the surgical ICU were evaluated over a 6 months period.

INTERVENTIONS

All classical risk factors for hypophosphatemia were recorded. A group of 8 moderate or severe hypophosphatemic patients were evaluated for hemodynamic data before and after a phosphorus load. Glucose phosphate was given over 30 min by the intravenous route. Dosage regimen was 0.4 mmol/kg weight for moderate hypophosphatemia and 0.8 mmol/kg weight for severe hypophosphatemia.

RESULTS

Risk factors were present in 134 patients and 60 patients were hypophosphatemic (44.8%). Only 3 risk factors were discriminant for hypophosphatemia: sepsis, diuretics and total parenteral nutrition. The mortality was higher in the hypophosphatemic group than in the normophosphatemic group (30% versus 15.2%; p < 0.05). Cardiac performance improved after phosphatemia normalization in all patients (cardiac index: 3.82 +/- 1.87 versus 4.52 +/- 1.83 1/min.m2; p < 0.01).

CONCLUSION

This study underlines the high incidence (28.8%) of hypophosphatemia in surgical intensive care patients and its association with a high mortality rate (30%). A short course of phosphotherapy improves cardiac index (+18%).

Osteomalacia with hypophosphatemia and hypercalciuria: a possible new variant of osteomalacia

A 12-year-old girl had a severe genu valgum deformity and osteomalacia with hypophosphatemia, hypercalciuria, and modestly elevated levels of 1,25-dihydroxyvitamin D3 and intact parathyroid hormone. This patient seems to have a different type of hypophosphatemic osteomalacia from that previously described.

Hypothesis: myopia of prematurity is caused by postnatal bone mineral deficiency

Myopia is a frequent finding in preterm children. The close association between myopia and retinopathy of prematurity (ROP) suggested a causal relationship, but myopia of prematurity without ROP has yet to be explained. An alternative explanation is presented: myopia is caused by postnatal ellipsoid deformation of the spheric eyeball, i.e. excessive elongation of the optical, as a result of a dolichocephalic deformation of the skull with a short frontal axis. This deformation of the skull is the direct result of bone mineral deficiency frequently observed in very low birth weight infants with increasing postnatal age. This hypothesis is supported by the results of a historical comparison of very low birth weight infants without and with supplementation with calcium and phosphorus that was given in order to prevent postnatal bone mineral deficiency. In the unsupplemented group 4 of 23 children (61%) needed spectacles but only 6 out of 55 (11%) children who were supplemented as babies (questionnaire). Refraction measurements showed myopia stronger than -1 o.d. in group 1 in 5 of 14 infants, whereas in group 2 only 2 out of 22 infants were myopic (P < 0.05).

Calcium, phosphorus and magnesium intakes correlate with bone mineral content in postmenopausal women

Qualitative and quantitative differences in the dietary habits of postmenopausal women were studied to assess their influence on bone health and osteoporosis. A total of 194 postmenopausal women were studied with forearm DEXA densitometry. 70 were osteoporotic and 124 served as controls. Women had been menopausal for 5-7 years, and had never been treated with hormone replacement or drug therapy. A 3-day dietary recall was completed on Sunday, Monday and Tuesday after the examination: the results were processed by computer and daily calcium, phosphorus and magnesium intakes were related to bone mineral content (BMC). Data were compared with Student's t-test and significance was assessed at p < 0.05. Regression analysis was performed to correlate BMC and intake levels. The dietary intake of calcium, phosphorus and magnesium was significantly reduced in osteoporotic women and correlated with BMC. Calcium and magnesium intakes were lower than the recommended daily allowance even in normal women. The results suggest that nutritional factors are relevant to bone health in postmenopausal women, and dietary supplementation may be indicated for the prophylaxis of osteoporosis. Adequate nutritional recommendations and supplements should be given before the menopause, and dietary evaluation should be mandatory in treating postmenopausal osteoporosis.

Type I glycogenosis with renal tubular dysfunction (presentation of two cases)

Two patients with hepatic glycogenosis associated with Fanconi syndrome are presented. Both patients were treated with a neutral phosphorus solution, an oral alkaline solution, cholecalciferol and uncooked cornstarch. The proximal renal tubular functions were corrected in the patient who used cornstarch properly, which may indicate a causal relationship between Fanconi syndrome and glycogenosis.

Effect of parenteral calcium and phosphorus therapy on mineral retention and bone mineral content in very low birth weight infants

HYPOTHESIS

If calcium and phosphorus are administered to very low birth weight infants in amounts larger than those currently used in standard parenteral nutrition solutions, apparent retention of calcium and phosphorus (intake minus urinary excretion) will increase and bone mineralization will improve.

DESIGN

Randomized, controlled, double-blind trial.

SETTING

Neonatal intensive care unit.

PATIENTS

Twenty-four very low birth weight infants (< 1.2 kg) expected to receive parenteral nutrition exclusively for approximately 3 weeks beginning 3 days after birth.

INTERVENTIONS

Infants received parenteral nutrition solutions, either the standard mixture containing 1.25 mmol calcium and 1.5 mmol phosphorus per deciliter (group STAND: n = 12, birth weight 921 +/- 171 gm, gestational age 27 +/- 2 weeks (mean +/- SD)) or 1.7 mmol calcium and 2.0 mmol phosphorus per deciliter (group HIGH: n = 12, 857 +/- 180 gm, 27 +/- 2 weeks).

MAIN OUTCOME MEASURES

Intake, urinary excretion, and apparent retention of calcium, phosphorus, and magnesium every 3 days during parenteral nutrition therapy. Serum indexes of mineral status twice during therapy. Bone mineral content of the distal segment of the left radius at 1, 4, 8, and 26 weeks.

RESULTS

Apparent calcium retention (1.2 +/- 0.2 vs 1.6 +/- 0.2 mmol.kg-1.d-1) and phosphorus retention (1.4 +/- 0.2 vs 1.8 +/- 0.4 mmol.kg-1.d-1) differed significantly (p < 0.01) between groups STAND and HIGH, respectively; neither changed with the duration of parenteral nutrition therapy. Serum calcium, magnesium, parathyroid hormone, 25-hydroxyvitamin D, and osteocalcin concentrations were similar in both groups. Serum phosphorus concentration was significantly higher in group HIGH than in group STAND (p = 0.025). The absolute bone mineral content and the rate of increase in bone mineral content between 1 and 4, 1 and 8, and 1 and 26 weeks were significantly greater in group HIGH than in group STAND.

CONCLUSIONS

Increased parenteral intakes of calcium and phosphorus resulted in greater retention of these minerals during parenteral nutrition therapy and in greater bone mineral content after therapy.

Effects of calcitriol and phosphorus therapy on the growth of patients with X-linked hypophosphatemia

Patients with X-linked hypophosphatemic rickets exhibit clinically evident derangements that include bowed legs and short stature. Although contemporary treatment may result in healing of the rachitic/osteomalacic disorder and straightening of the lower extremities, therapy often does not stimulate growth. Whether such persistent short stature is related to the variable physical manifestations of the disease, the baseline biochemistries, and/or the biochemical response to treatment remains unknown. Therefore, we studied 12 children with X-linked hypophosphatemia to determine if their growth response to calcitriol/phosphorus therapy was dependent upon anthropomorphic characteristics and/or the pre- and posttreatment biochemistries. We observed that growth responsive and resistant youths exhibited similar serum calcium, phosphorus, and creatinine levels at presentation and during therapy. In addition, sexual development was indistinguishable in both groups and growth kinetics appeared independent of physical deformity. In contrast, growth resistant youths presented at less than the 5th percentile whereas growth responsive children were at the 15th percentile or greater. Thus, our data indicate that growth response to calcitriol/phosphate therapy is not a consequence of the biochemical response to therapy or physical deformities. Rather, the criterion that best predicts the growth response is the height percentile at the inception of therapy.

Severe hypophosphatemia in postoperative patients

Severe hypophosphatemia may develop in postoperative patients for several reasons including alcohol withdrawal, diabetic ketoacidosis, nutritional recovery (refeeding) syndrome, and severe respiratory alkalosis. Severe hypophosphatemia may result in central nervous system abnormalities, muscle weakness, and renal, hepatic, cardiac, and respiratory dysfunction. Hypophosphatemia may be prevented by close monitoring of phosphorus concentrations in serum, especially in patients predisposed to developing this problem. Proper techniques for the maintenance and repletion of phosphate for both enteral and parenteral use are described.

Effect of cyclical therapy with phosphorus and etidronate on axial bone mineral density in postmenopausal osteoporotic women

Forty seven women with postmenopausal osteoporosis and at least one but no more than four vertebral compression fractures received sequential and cyclical therapy with phosphorus and etidronate (p/etid). During the same 2-year period of observation, three other groups of patients received either sodium fluoride (n = 12), estrogen replacement therapy (n = 12), or vitamin D and calcium (Ca++) alone (n = 15). Axial bone mineral density (BMD) was measured by means of dual-photon absorptiometry. Lateral thoracic and lumbar spine radiographs were taken to assess fractures. Bone mineral density increased from baseline during p/etid therapy: Mean 15.7 +/- 1.6% (SD) (P less than 0.001). During the same time, the patients in the sodium fluoride group showed a comparable increase in their BMD from baseline: mean 15.7 +/- 1.1% (P less than 0.001). During the first year of therapy, patients in the estrogen replacement group had an increase in their BMD from baseline: mean: 4.6% +/- 1.1% (P less than 0.05). No change in BMD was seen in the control group that received vitamin D and Ca++ alone. No patient who received p/etid, sodium fluoride, or estrogen replacement therapy had any new vertebral compression fractures or height loss, whereas in the control group that received vitamin D and Ca++ alone 6 out of 15 had height loss and at least one new vertebral fracture (P less than 0.01). p/etid therapy increases BMD in women with postmenopausal osteoporosis comparable to sodium fluoride but without side effects or toxicity and stabilizes vertebral compression fractures.

Effects of dietary ammonium chloride and variations in calcium to phosphorus ratio on silica urolithiasis in sheep

Ammonium chloride was added to diets varying in Ca content to evaluate its potential in preventing silica urolith formation in sheep. A 2 x 2 factorial experiment involved wether lambs with ad libitum access to a diet of 50% grass hay and 50% ground oats plus supplement. The basal diet contained on a DM basis 3.3% SiO2, .31% Ca, .22% P, 11.6% CP, and 26% ADF. Treatments (38 to 39 lambs/treatment) consisted of a control (C), limestone to increase dietary calcium to .6% (L), 1% ammonium chloride (A), and L + A (LA). After a 118-d experimental period, siliceous kidney deposits were found only in C and L, with silica making up 93% to 95% of the urolithic ash. Urolith incidences were 13% (C) and 18% (L), respectively. The lack of urolith development in lambs fed A and LA (ammonium chloride effect, P less than .01) and a trend toward a lower urolith incidence in C vs L (P less than .02) support the hypothesis that acid-forming effects of the diet and a reduction in the dietary Ca to P ratio reduce silica urolith formation.

Potential role of acute hypophosphatemia during hypokalemic periodic paralysis attack

A paralysis attack was induced by glucose load in a patient with hypokalemic periodic paralysis. A profound drop in serum phosphorus was observed (from 3.0 to 0.8 mg/dl) in parallel to the serum potassium decrease. The potential role of phosphorus metabolism in the pathophysiology of muscle weakness in this disease is discussed.

[Oncogenic hypophosphatemic osteomalacia]

In the courses of six years a severe hypophosphataemic osteomalacia, painful motor impairment and multiple rib fractures developed in a 51-year-old man. The symptoms gradually improved within one year under treatment with 3 micrograms daily of 1,25-dihydroxycholecalciferol, 3 g phosphorus and 3 g calcium, and biochemical parameters and the bone scintigram became normal. Ultimately, computed tomography, scintigraphy and digital subtraction angiography revealed a highly vascularized tumour in the condylar aspect of the right femur, and it was chiselled out. Histologically it was a mesenchymal phosphaturic tumour of haemangiopericytoma type of questionable benignity. After the operation the patient was symptom-free for some weeks without any drug treatment, but the latter was then resumed because of renewed bone pain. By now, two years later, he is essentially without pain and has full mobility. However, repeat scintigraphy and angiography revealed renewed tumour growth in the right femoral condyle.

Absent intestinal response to calciferols in hereditary resistance to 1,25-dihydroxyvitamin D: documentation and effective therapy with high dose intravenous calcium infusions

We describe a patient with an absent intestinal response to 1,25-dihydroxyvitamin D [1,25-(OH)2D] and the beneficial effects of treatment with high dose iv calcium infusion. The patient presented with severe rickets despite therapy with extraordinarily high doses of 1 alpha-hydroxyvitamin D3 or 1,25-(OH)2D3. Unidirectional intestinal fractional calcium absorption when he was not treated with any calciferol was 14% (normal, 20-70%), as measured with stable calcium isotopes; no increase in calcium absorption occurred when serum 1,25-(OH)2D levels were more than 50-fold elevated. Cultured skin fibroblasts contained no detectable 25-hydroxyvitamin D3-24-hydroxylase activity in response to 1,25-(OH)2D3 (10(-9)-10(-6) mol/L). High dose iv calcium infusions and oral phosphorus supplementation for 135 days improved or normalized biochemical parameters and resulted in radiographic healing of the rachitic lesions. We conclude that 1) this patient had no response to 1,25-(OH)2D3 in vivo and in vitro; 2) long term parenteral calcium infusions were effective therapy in managing the patient's severe resistance to 1,25-(OH)2D; and 3) stable calcium isotopes are useful for measuring low levels of fractional calcium absorption.

Evaluation of mineral metabolism and bone turnover in osteoporotic females treated with phosphorus and salmon calcitonin

Twenty-five patients with radiological and clinical evidence of osteoporosis were studied. Nineteen patients received oral phosphorus at a dose of 1,000 mg/die for 10 days followed by salmon calcitonin (100 U MRC/die) for 20 days. Six patients received only oral calcium at a dose of 1,000 mg/die). In the first group, a significant increase in serum osteocalcin and parathyroid hormone, after administration of phosphorus and persisting after treatment with salmon calcitonin, was found. No variation in the controls was observed. In a later study, a significant increase in serum 1,25 dihydroxyvitamin D (1,25(OH)2D3), after receiving phosphorus and persisting after salmon calcitonin, was demonstrated. In accordance with the authors' results, phosphorus could be considered a useful activator of bone formation and this stimulus by parathyroid hormone was mediated. Finally, the positive effects of phosphorus on circulating 1,25(OH)2D3 must be considered for a good treatment protocol of osteoporosis.

Phosphorus deficiency syndrome in very low birth weight infants

Inadequate dietary phosphorus intake is a contributing factor to the occurrence of metabolic bone disease in very low birth weight infants. This article reviews the clinical presentation and the pathophysiology of the phosphorus deficiency syndrome in premature infants. Recommendations for therapy and prevention of phosphorus deficiency are presented.