Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 14-year-old boy presented with the clinical and radiological features of rickets. Serum inorganic phosphate levels were constantly low, whereas serum calcium and parathyroid hormone levels were within the normal range. Laboratory investigation did not show any evidence for vitamin-D deficiency, chronic renal insufficiency, Fanconi syndrome, tubular acidosis, hepatic disease or intestinal malabsorption. A family study comprising 34 members over four generations revealed 10 other individuals to be affected and the mode of inheritance to be autosomal dominant. In addition to hypophosphataemia and normocalcaemia, the disease is characterized by elevated serum 1,25 dihydroxyvitamin D levels and hypercalciuria. This hereditary syndrome of renal hypophosphataemia differs from the common familial X-linked hypophosphataemia and the recently described autosomal recessive hypophosphataemic rickets with hypercalciuria by its dominant mode of inheritance; it differs from hypophosphataemic non-rachitic bone disease by the elevated serum 1,25 dihydroxyvitamin D levels and hypercalciuria.
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PMID:Autosomal dominant hypophosphataemia with elevated serum 1,25 dihydroxyvitamin D and hypercalciuria. 315 20

Two patients with extensive tumoral calcinosis were treated with aluminium hydroxide. Initial metabolic studies showed positive calcium and phosphorus balances which became negative with aluminium hydroxide treatment. One subject, who had renal impairment, developed transient hypercalcaemia, parathyroid suppression, low levels of 1,25-dihydroxyvitamin D and calcium malabsorption during treatment with aluminium hydroxide. The second patient developed calcium malabsorption due to vitamin D deficiency. When she was replete with vitamin D there were supranormal levels of 1,25-(OH)2D in the serum and enhanced calcium absorption during treatment with aluminium hydroxide. Both subjects developed hypercalciuria and there was dissolution of many of the calcific tumours. The patient with renal impairment accumulated aluminium in the bone.
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PMID:Tumoral calcinosis: clinical and metabolic response to phosphorus deprivation. 365 64

To define the mechanism for the hypercalciuria in spontaneously hypertensive rats (SHR), Ca clearance was evaluated in fasted 23-wk-old SHR and normotensive Wistar Kyoto (WKy) controls. There was no exaggerated calciuria before or after parathyroidectomy. Ca balance was therefore measured in the nonfasted animals, which revealed hyperabsorption in SHR of both sexes with increments 10-fold that of Ca excretion, supporting the primacy of intestinal hyperabsorption. In situ duodenal Ca uptake was also increased in the SHR. Parathyroidectomy did not affect the hyperabsorption. Hypercalcemia (total and ionized) and hypercalciuria in SHR associated with reduced adenosine 3',5'-cyclic monophosphate excretion, were abolished by fasting. Correction of hypertension for 6 mo failed to abolish the hypercalciuria. Bone Ca deposits were increased in 1-yr-old SHR. Ten-week-old SHR, in contrast, displayed mild malabsorption. Our data do not support the "renal leak" hypothesis. Instead, the adult SHR is characterized by increased Ca retention due to primary hyperabsorption, absorptive hypercalciuria, and increased bone Ca deposition. These phenomena are independent of sex, parathyroid hormone, and treatment of the established hypertension.
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PMID:Evidence for an intestinal mechanism in hypercalciuria of spontaneously hypertensive rats. 649 32

The state of vitamin D nutrition depends on synthesis in the skin under the influence of sunlight as well as on dietary intake. In European countries that do not fortify milk with vitamin D, reduced sun exposure is the major factor leading to a fall in body stores of vitamin D with age and to a high frequency of hypovitaminosis D in the elderly sick. In the US, because vitamin D is added to milk and the use of vitamin D supplements is more common, the dietary intake of vitamin D is relatively more important than in Europe, and the total vitamin D intake and body stores of vitamin D are generally higher. Nevertheless, body stores of vitamin D probably fall with age in the US as they do in Europe, and it is likely that some sick elderly persons in the US, especially among those confined to institutions, become vitamin D deficient. For several reasons, the vitamin D requirement increases with age, and a total supply of 15 to 20 micrograms/day (600 to 800 IU) from all sources is recommended. Special attention should be paid to persons most likely to need supplementation, such as the housebound, persons with malabsorption, and persons with interruption of the enterohepatic circulation. Osteomalacia, the bone disease produced by severe vitamin D deficiency, is less common in the US than in Europe, but subclinical vitamin D deficiency may contribute to the pathogenesis of hip fractures, both through increased liability to fall and through PTH-mediated bone loss. The extent to which vitamin D deficiency contributes to hip fractures in the US is unknown, and is an important area for future research. Excess intake of vitamin D or of its metabolites may result in hypercalcemia and extra-osseous calcification, particularly in arterial walls and in the kidney, leading to chronic renal failure. The dose of vitamin D that causes significant hypercalcemia is highly variable between individuals but is rarely less than 1000 micrograms/day. Smaller doses can cause hypercalciuria and nephrolithiasis and possibly impaired renal function. Vitamin D administration may raise plasma cholesterol but there is no convincing evidence that the risk of myocardial infarction is increased. The recommended total supply for the elderly of 20 micrograms/day is most unlikely to be harmful, except in patients with sarcoidosis or renal calculi.
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PMID:Vitamin D and bone health in the elderly. 676 68

A 60-year-old woman was evaluated for bone pain and incapacitating weakness. Initial laboratory studies showed a serum calcium level of 10.1 mg/dL, severe hypophosphatemia (1.1 mg/dL), and an elevated alkaline phosphatase level. X-ray films showed changes consistent with osteomalacia. Further studies revealed hypercalciuria (448 mg/24 hr) but absent urinary phosphorus. These data indicated phosphate malabsorption. Excessive use of an aluminum hydroxide-containing antacid was the cause of this patient's failure to absorb dietary phosphate. The features of this syndrome are reviewed to increase physicians' awareness of this illness, which occurs particularly in the elderly and is easily treated.
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PMID:Osteomalacia and weakness from excessive antacid ingestion. 743 92

The effects of endocrine disease on bone mass continue to attract attention. Investigations include the effects on the skeleton of thyroid disease, primary hyperparathyroidism, and their treatment. The effect of growth hormone replacement in adults with panhypopituitarism has also been investigated; children with treated growth hormone deficiency appear to reach adulthood with low bone mass. The indications for surgery in asymptomatic primary hyperparathyroidism have recently been reviewed. The associations between autoimmune thyroid disease and connective tissue disease have been investigated. Although patients with Graves' disease are frequently positive for antinuclear antibodies, there appears to be no increased risk of systemic autoimmune disease. The possible pathogenesis of diabetic bone disease via calcium malabsorption, hypercalciuria, reduced bone formation, and collagen abnormalities has been reviewed. A long-term study has clarified the links among diabetic control, limited joint mobility, nephropathy, and retinopathy. The possible mechanisms by which pregnancy may induce remission in rheumatoid arthritis have been discussed.
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PMID:Endocrine disease. 843 94

1. The best way to prevent early growth failure in children with renal disease is by the use of specified nutrition and appropriate buffer, activated vitamin D, and calcium-containing phosphate binders as needed. With prenatal diagnosis of anatomically abnormal kidneys available, this type of early intervention may be much more feasible in the 1990s. 2. Supplemental sodium and water in children with polyuria and intravascular volume depletion may prevent growth failure. Cow milk is detrimental in this group of individuals because of high solute and protein load, often causing intravascular volume depletion, hyperphosphatemia, and acidosis. 3. Children with acquired glomerular disease may need sodium restriction and, if treated with steroids, a diet low in saturated fat. 4. Children with nephrotic syndrome and severe edema should be evaluated for malabsorption and subsequent malnutrition. Protein intake should be supplemented only at the RDA and to replace ongoing losses. Long-term sodium restriction is appropriate. Hyperlipidemia should be monitored: if nephrosis is chronic, a low saturated fat diet should be instituted. Angiotensin-converting enzyme inhibitors can decrease urinary protein loss and may ameliorate hyperlipidemia. Children resistant to therapy can have very high morbidity. 5. Children with <50 % of normal creatinine clearance should have PTH measured and activated vitamin D therapy should be started if PTH is elevated more than two to three times normal. Thereafter careful monitoring of calcium, phosphorus, and PTH is crucial to prevent renal osteodystrophy, low turnover bone disease, and hypercalcemia with hypercalciuria and nephrocalcinosis. 6. Children with tubular defects with severe polyuria also may benefit from low-solute, high-volume feedings. 7. All physicians caring for children with renal disease should have pediatric nephrology consultation available. Prevention of growth failure is much more cost effective than pharmacologic therapy. Before initiating growth hormone treatment for growth retardation, assiduous treatment of co-existing renal osteodystrophy and provision of optimal nutritional intake should be accomplished.
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PMID:Nutritional management of the child with mild to moderate chronic renal failure. 876 44

It is well recognized that patients with postmenopausal osteoporosis usually exhibit some degree of calcium malabsorption and commonly have low serum concentrations of 1,25-dihydroxyvitamin D (calcitriol). Administration of calcitriol has been shown to normalize calcium absorption in patients with osteoporosis and, over the long term may have a stimulating effect on bone formation. Clinical trials have shown a significant reduction in osteoporotic fractures among calcitriol-treated patients. Hypercalcemia and hypercalciuria are infrequent complications of calcitriol therapy with physiologic doses (0.25 microgram twice daily), and are most commonly related to excessive calcium intake (i.e., > 1000 mg daily).
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PMID:The role of vitamin D in the pathogenesis and treatment of osteoporosis. 885 46

Osteoporosis is increasingly recognised in men. Low bone mass, risk factors for falling and factors causing fractures in women are likely to cause fractures in men. Bone mass is largely genetically determined, but environmental factors also contribute. Greater muscle strength and physical activity are associated with higher bone mass, while radial bone loss is greater in cigarette smokers or those with a moderate alcohol intake. Sex hormones have important effects on bone physiology. In men, there is no abrupt cessation of testicular function or 'andropause' comparable with the menopause in women; however, both total and free testosterone levels decline with age. A common secondary cause of osteoporosis in men is hypogonadism. There is increasing evidence that estrogens are important in skeletal maintenance in men as well as women. Peripheral aromatisation of androgens to estrogens occurs and osteoblast-like cells can aromatise androgens into estrogens. Human models exist for the effects of estrogens on the male skeleton. In men aged > 65 years, there is a positive association between bone mineral density (BMD) and greater serum estradiol levels at all skeletal sites and a negative association between BMD and testosterone at some sites. It is crucial to exclude pathological causes of osteoporosis, because 30 to 60% of men with vertebral fractures have another illness contributing to bone disease. Glucocorticoid excess (predominantly exogenous) is common. Gastrointestinal disease predisposes patients to bone disease as a result of intestinal malabsorption of calcium and colecalciferol (vitamin D). Hypercalciuria and nephrolithiasis, anticonvulsant drug use, thyrotoxicosis, immobilisation, liver and renal disease, multiple myeloma and systemic mastocytosis have all been associated with osteoporosis in men. It is possible that low-dose estrogen therapy or specific estrogen receptor-modulating drugs might increase BMD in men as well as in women. In the future, parathyroid hormone peptides may be an effective treatment for osteoporosis, particularly in patients in whom other treatments, such as bisphosphonates, have failed. Men with idiopathic osteoporosis have low circulating insulin-like growth factor-1 (IGF-1; somatomedin-1) concentrations, and IGF-1 administration to these men increases bone formation markers more than resorption markers. Studies of changes in BMD with IGF-1 treatment in osteoporotic men and women are underway. Osteoporosis in men will become an increasing worldwide public health problem over the next 20 years, so it is vital that safe and effective therapies for this disabling condition become available. Effective public health measures also need to be established and targeted to men at risk of developing the disease.
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PMID:Osteoporosis in men. New insights into aetiology, pathogenesis, prevention and management. 988 98

In order to examine the etiology of refractory rickets, we evaluated the case records of patients presenting between 1990 and 2002. Subjects with impaired renal functions were excluded. Of 131 patients, 25.9 % each had hypophosphatemic rickets and distal renal tubular acidosis (RTA), 19.6 %vitamin D dependent rickets (VDDR), 11.3 % proximal RTA, 9.1 % liver disease and 6.1 % malabsorption. A significant proportion of patients with VDDR and proximal RTA showed deformities in the first year of life, whereas those with distal RTA and hypophosphatemic rickets presented later. Patients with hypophosphatemic rickets had predominant involvement of lower limbs; hypercalciuria was found in 4. Distal RTA was associated with marked rickets and normal levels of alkaline phosphatase. Hypophosphatemia and low tubular reabsorption of phosphate, though characteristic of hypophosphatemic rickets, was also seen in patients with VDDR (19.2%) and distal RTA (17.6 %). Our findings suggest that application and interpretation of appropriate investigations are useful in determining the cause of non-azotemic refractory rickets allowing initiation of specific therapy.
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PMID:Non-azotemic refractory rickets in Indian children. 1569 54


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