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)

Celiac disease is an intestinal disease due to an abnormal immuno-mediated response to gluten and other peptides from different cereals in genetically susceptible subjects. Several systemic alterations, including bone alterations, may be present in affected subjects. Once considered rare, it is now known to be quite frequent in both Europe and North America, as the recent availability of specific serological markers has drastically changed our perspective on its prevalence. The diagnosis of celiac disease may be very difficult because the clinical picture is highly variable and the characteristic intestinal signs and symptoms may be completely absent. Among the extra-intestinal alterations, bone mass decrease and bone metabolism derangement are frequently present and can be the only signs of an otherwise silent celiac disease. Clinical and epidemiological data are now plentiful but no conclusive data on the pathogenesis of bone involvement in celiac disease are available yet. Bone alterations were once thought to derive from calcium and vitamin D deficiency secondary to simple intestinal malabsorption, but now a more complex interaction between cytokines and local/systemic factors influencing bone formation and reabsorption is envisaged, Also, there is now substantial evidence supporting a lifelong gluten-free diet as the first-choice therapy for celiac disease, and as far as we know, this is the only effective measure to restore bone metabolism to an apparent normality. In the young, an early-started gluten-free diet can even lead to a satisfactory recovery of bone mass. In adults, however, there is no spontaneous recovery, and there are no conclusive data on the efficacy of standard therapies for osteoporosis in reducing the fracture risk. For these reasons, we feel that a review of the clinical findings on bone problems in celiac disease may be useful for both gastroenterologists and osteoporosis specialists.
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PMID:Bone and celiac disease. 1450 28

The goal of osteoporosis therapy is reduction of fracture risk. In randomized controlled trials, relative risk of fracture is determined by comparing the absolute fracture rate of a treatment group to a control group. Fracture risk cannot be measured in individual patients being treated for osteoporosis. Since osteoporosis is a silent disease, and some patients may not respond to therapy, a surrogate test for reduction of fracture risk is often used-most commonly a bone density test. A proposed definition of nonresponse is: A decrease in bone mineral density greater than the Least Significant Change at the 95% level of confidence. The Least Significant Change is a value based on bone density measurements in patients and calculated according to well-established standards. There are other candidates for measuring responsiveness to therapy, most notably biochemical markers of bone metabolism, but none is as well validated or standardized as bone density testing. Causes of nonresponse include poor adherence, co-morbid conditions, calcium and vitamin D deficiency, malabsorption, metabolic factors, wrong dose, wrong dosing interval, and lack of efficacy. A bone density increase or stability of bone density is associated with fracture risk reduction in approved osteoporosis therapies, while a bone density decrease is cause for clinical concern. The proposed definition of nonresponse identifies a subset of patients who may require a change of therapy and/or additional medical intervention. More data are needed to develop guidelines for clinicians. Further study is suggested.
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PMID:Nonresponders to osteoporosis therapy. 1471 42

Weight loss after biliopancreatic diversion or duodenal switch is due to decreased calorie absorption secondary to fat malabsorption. Fat malabsorption may also cause essential fat-soluble vitamin deficiencies, which may have severe clinical consequences and alter calcium metabolism. Serum vitamins A, D, E, and K, zinc, parathyroid hormone, corrected calcium, and alkaline phosphatase levels were measured in a cohort of patients who had previously undergone biliopancreatic diversion. Two bariatric surgery units were involved in the study: New York University School of Medicine (New York, NY), and the Wesley Medical Center (Brisbane, Australia). A total of 170 patients completed the study. The incidence of vitamin A deficiency was 69%, vitamin K deficiency 68%, and vitamin D deficiency 63% by the fourth year after surgery. The incidence of vitamin E and zinc deficiency did not increase with time after surgery. The incidence of hypocalcemia increased from 15% to 48% over the study period with a corresponding increase in serum parathyroid hormone values in 69% of patients in the fourth postoperative year. There is a progressive increase in the incidence and severity of hypovitaminemia A, D, and K with time after biliopancreatic diversion and duodenal switch. Calcium metabolism is affected with an increasing incidence of secondary hyperparathyrodisim and evidence of increased bone resorption in 3% of patients. Long-term nutritional monitoring is necessary after malabsorptive operations for morbid obesity.
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PMID:Serum fat-soluble vitamin deficiency and abnormal calcium metabolism after malabsorptive bariatric surgery. 1474 35

Hyperparathyroidism is a disease characterized by hypercalcemia with hypophosphoremia resulting from increased secretion of parathyroid hormone (PTH). The disease may be divided into 3 forms: a) primary, b) secondary, c) tertiary (secondary refractory form). Primary hyperparathyroidism is rare in children; hyperplasia is more frequent during the early years of life (neonates and infants) and is difficult to distinguish from adenoma in children. The disease may be asymptomatic; elevated calcemia levels (>12 <13.5 mg/dl) are accompanied by anorexia, asthenia and persistent stipsis; severely elevated concentrations (>13.5 mg/dl) are accompanied by nausea, vomiting, polyuria due to osmosis, with dehydration and progressive onset of lethargy, stupor and coma. Osteopenia or osteitis fibrosa cystica may be present due to augmented bone resorption. Height and weight increases are altered due to anorexia and dehydration. Differential diagnosis includes iatrogenic causes of hypercalcemia (excessive vitamin D intake, prolonged immobilization, etc.) and idiopathic familial hypercalcemia. Emergency treatment is required in cases of extremely elevated hypercalcemia (Ca >13.5-14 mg/dl), due to risk of injury to the heart, the central nervous system, the gastrointestinal tract and the kidneys. The 4 cardinal points of treatment are: hydration, calciuresis, inhibition of bone calcium resorption, treatment of the cause underlying hyperparathyroidism. Secondary hyperparathyroidism is found in cases where chronic hypocalcemia is present, particularly in chronic renal failure, untreated deficiency rickets, chronic intestinal malabsorption, hepatobiliary disease, types I and II vitamin D-dependent rickets, tubular acidosis or Fanconi's syndrome. The tertiary form is distinguished by the autonomous nature of the parathyroid glands which have become hypertrophic/hyperplastic due to uncontrollable, chronic severe renal failure. It can also be of iatrogenic origin due to excessive intake of inorganic phosphates in familial hypophosphatemic rickets or chronic vitamin D deficiency.
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PMID:Hyperparathyroidism. 1524 24

Chronic pancreatitis is a longlasting inflammatory disease manifested clinically in the advanced stage by malabsorption syndrome. Its manifestations include also changes in the calcium metabolism and the occurrence of osteoporosis and osteomalacia or their combination. The objective of the study was to assess the vitamin D3 blood concentration in patients with chronic pancreatitis. The group comprised 15 patients (8 men and 7 women), median age 45.0 years. The authors found a significantly reduced serum concentration of vitamin D3 (p < 0.01) in patients with chronic pancreatitis. They assume that vitamin D deficiency is one of the decisive causes of bone complications in prolonged pancreatitis. Supplementation with vitamin D or its metabolites is then a necessary part of preventive and therapeutic provisions.
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PMID:[Vitamin D deficiency as one of the causes of bone changes in chronic pancreatitis]. 1564 Dec 50

Hypercalcemia has been described in patients with a number of granulomatous diseases, including sarcoidosis and mycobacterial infection. Disordered vitamin D metabolism is the root cause for the elevated serum calcium levels. A similar mechanism of abnormal vitamin D metabolism explained the hypercalcemia occurring in patients with lymphoma. Crohn's disease is a granulomatous disorder that is more commonly associated with hypocalcemia caused by poor calcium intake and decreased intestinal calcium absorption related to vitamin D deficiency as a consequence of malabsorption. A man with Crohn's disease who presented with hypercalcemia and acute renal failure is described. Biochemical parameters showed an elevated 1,25-dihydroxyvitamin D level, with a low-normal 25-hydroxyvitamin D level and decreased parathyroid hormone level. Inflammatory bowel disease had been clinically active during the preceding 2 months. With resolution of gastrointestinal symptoms, serum calcium, vitamin D, and parathyroid hormone levels returned to normal. Serum creatinine levels decreased toward normal. Angiotensin-converting enzyme (ACE) levels have been reported to be elevated in patients with sarcoidosis, particularly in the setting of active disease with hypercalcemia. Controversy exists about ACE levels in the face of active Crohn's disease: 1 report noted elevated levels, whereas other publications reported depressed levels. Our patient had an elevated ACE level in the setting of active bowel disease and hypercalcemia, and ACE levels returned to normal with resolution of gastrointestinal symptoms.
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PMID:Hypercalcemia due to excess 1,25-dihydroxyvitamin D in Crohn's disease. 1569 36

A significant number of Australians are deficient in vitamin D--it is a fallacy that Australians receive adequate vitamin D from casual exposure to sunlight. People at high risk of vitamin D deficiency include elderly people (particularly those in residential care), people with skin conditions where avoidance of sunlight is advised, those with dark skin (particularly if veiled), and those with malabsorption. Exposure of hands, face and arms to one-third of a minimal erythemal dose (MED) of sunlight (the amount that produces a faint redness of skin) most days is recommended for adequate endogenous vitamin D synthesis. However, deliberate sun exposure between 10:00 and 14:00 in summer (11:00-15:00 daylight saving time) is not advised. If this sun exposure is not possible, then a vitamin D supplement of at least 400 IU (10 microg) per day is recommended. In vitamin D deficiency, supplementation with 3000-5000 IU ergocalciferol per day (Ostelin [Boots]; 3-5 capsules per day) for 6-12 weeks is recommended. Larger-dose preparations of ergocalciferol or cholecalciferol are available in New Zealand, Asia and the United States and would be useful in Australia to treat moderate to severe vitamin D deficiency states in the elderly and those with poor absorption; one or two annual intramuscular doses of 300 000 IU of cholecalciferol have been shown to reverse vitamin D deficiency states.
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PMID:Vitamin D and adult bone health in Australia and New Zealand: a position statement. 1618 Feb 68

A nearly 5 year-old boy presented with proximal muscle weakness, reduced muscle bulk, a positive Gower sign and Trendelenburg gait. He was known to have cholestatic liver disease. Investigations revealed markedly low serum total calcium, elevated alkaline phosphatase, very low serum 25-hydroxyvitamin D, and radiographs consistent with active rickets despite the ongoing administration of a water-soluble preparation of vitamin D. Only i.v. calcitriol acutely corrected the hypocalcemia, despite trying several oral preparations, suggesting that malabsorption secondary to chronic liver disease was the cause of his rickets. Intramuscular calciferol quickly corrected his muscle weakness and X-ray findings. Myopathy secondary to vitamin D deficiency is an uncommon diagnosis in children. Intermittent calciferol is an inexpensive and practical treatment for vitamin D deficiency, especially if associated with malabsorption.
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PMID:Treatment of malabsorption vitamin D deficiency myopathy with intramuscular vitamin D. 1612 49

Vitamin D3 is synthesized in the skin during summer under the influence of ultraviolet light of the sun, or it is obtained from food, especially fatty fish. After hydroxylation in the liver into 25-hydroxyvitamin D (25(OH)D) and kidney into 1,25-dihydroxyvitamin D (1,25(OH)2D), the active metabolite can enter the cell, bind to the vitamin D-receptor and subsequently to a responsive gene such as that of calcium binding protein. After transcription and translation the protein is formed, e.g. osteocalcin or calcium binding protein. The calcium binding protein mediates calcium absorption from the gut. The production of 1,25(OH)2D is stimulated by parathyroid hormone (PTH) and decreased by calcium. Risk factors for vitamin D deficiency are premature birth, skin pigmentation, low sunshine exposure, obesity, malabsorption and advanced age. Risk groups are immigrants and the elderly. Vitamin D status is dependent upon sunshine exposure but within Europe, serum 25(OH)D levels are higher in Northern than in Southern European countries. Severe vitamin D deficiency causes rickets or osteomalacia, where the new bone, the osteoid, is not mineralized. Less severe vitamin D deficiency causes an increase of serum PTH leading to bone resorption, osteoporosis and fractures. A negative relationship exists between serum 25(OH)D and serum PTH. The threshold of serum 25(OH)D, where serum PTH starts to rise is about 75nmol/l according to most surveys. Vitamin D supplementation to vitamin D-deficient elderly suppresses serum PTH, increases bone mineral density and may decrease fracture incidence especially in nursing home residents. The effects of 1,25(OH)2D and the vitamin D receptor have been investigated in patients with genetic defects of vitamin D metabolism and in knock-out mouse models. These experiments have demonstrated that for active calcium absorption, longitudinal bone growth and the activity of osteoblasts and osteoclasts both 1,25(OH)2D and the vitamin D receptor are essential. On the other side, bone mineralization can occur by high ambient calcium concentration, so by high doses of oral calcium or calcium infusion. The active metabolite 1,25(OH)2D has its effects through the vitamin D receptor leading to gene expression, e.g. the calcium binding protein or osteocalcin or through a plasma membrane receptor and second messengers such as cyclic AMP. The latter responses are very rapid and include the effects on the pancreas, vascular smooth muscle and monocytes. Muscle cells contain vitamin D receptor and several studies have demonstrated that serum 25(OH)D is related to physical performance. The active metabolite 1,25(OH)2D has an antiproliferative effect and downregulates inflammatory markers. Extrarenal synthesis of 1,25(OH)2D occurs under the influence of cytokines and is important for the paracrine regulation of cell differentiation and function. This may explain that vitamin D deficiency can play a role in the pathogenesis of auto-immune diseases such as multiple sclerosis and diabetes type 1, and cancer. In conclusion, the active metabolite 1,25(OH)2D has pleiotropic effects through the vitamin D receptor and vitamin D responsive elements of many genes and on the other side rapid non-genomic effects through a membrane receptor and second messengers. Active calcium absorption from the gut depends on adequate formation of 1,25(OH)2D and an intact vitamin D receptor. Bone mineralization mainly depends on ambient calcium concentration. Vitamin D metabolites may play a role in the prevention of auto-immune disease and cancer.
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PMID:Vitamin D physiology. 1656 71

Osteomalacia is characterized by defective mineralization and low bone mineral density (BMD). Clinical and biochemical improvements typically occur within a few weeks of starting treatment, though the bone mineral deficits may take longer to correct. We report a case series of 26 patients with frank osteomalacia (pseudo fractures on X-rays, elevated serum total alkaline phosphatase and parathyroid hormone, normal/low serum calcium and phosphorus, and low serum 25-hydroxy vitamin D) who were followed-up for changes in BMD during treatment using dual- energy X-ray absorptiometry (DXA). There were 23 patients with nutritional vitamin D deficiency, 2 with malabsorption syndrome, and 1 with renal tubular acidosis. All patients were treated with vitamin D and calcium; the 3 patients with associated disorders were treated accordingly. At baseline, there was low BMD at all sites tested. The rate of increase in vertebral and hip BMD was rapid in the initial few months, which subsequently slowed down. In contrast to the large increases in BMD at the femoral neck and lumbar spine, the radial BMD did not recover. At the time when most patients had marked clinical and biochemical improvement (2.8+/-1.4 mo), the vertebral and hip BMD, although improved from baseline, had not completely recovered. Bone loss at the forearm (cortical site) appears to be largely irreversible. Although the clinical correlates of these changes are presently unclear, BMD measurements are useful in assessing the initial severity of bone loss as well as the response to therapy.
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PMID:Changes in bone mineral density following treatment of osteomalacia. 1673 41


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