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Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Seven patients with neuropathy associated with vitamin B12 deficiency are reported. Four of them had other signs of malabsorption aside from the abnormal Schilling test. The neuropathy was diagnosed on the basis of the whole clinical picture and the neurophysiological findings. The pathogenesis of the peripheral nerve disease is discussed in the light of the evidence in the literature.
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PMID:Peripheral neuropathy with vitamin B12 deficiency. 6 53

Fourteen patients with ileal dysfunction due to resection or bypass were encountered over an 18-month period. Symptoms had been present for a mean period of 1.8 years. Diarrhoea was a universal symptom, and varied from mild to incapacitating. Weight loss, due in part to malabsorption and in part to the patients' fear of eating, occurred in 10 of 14 patients. The chief metabolic abnormalities were steatorrhoea and hypokalaemia. Vitamin B12 deficiency, folate deficiency, anaemia, hypoalbuminaemia, hypocalcaemia, hypomagnesaemia, hyperoxaluria, and an abnormal prothrombin ratio were less frequently seen. Treatment with cholestyramine and/or long-chain fat restriction effectively reduced diarrhoea in every case, and this was supplemented by replacement of specific deficiencies. There was little added benefit from non-specific antidiarrhoeal agents. It was found that the major symptoms of ileal dysfunction are readily treated, but that attention should also be given to a number of nutritional deficiencies.
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PMID:Consequences of ileal dysfunction: an approach to management. 10 34

A baby girl, born prematurely and with Down's syndrome, is hospitalized at the age of 51 days for a megaloblastic anemia. The anemia was caused by a selective malabsorption of vitamin B12 (Imerslund's syndrome), even in presence of intrinsic factor. The pathogenesis of different causes of vitamin B12 deficiency is discussed and the favourable development of this case after four years of treatment is shown.
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PMID:[Congenital malabsorption of vitamin B12 (Imerslund's syndrome) in a premature girl with Down's syndrome (author's transl)]. 15 16

The case is described of an infant who suffered from progressive, severe dystrophy, hemolytic and megaloblastic anemia, hematuria, proteinuria and slight uremia. He died at 4 months of age following two acute episodes of heart failure. Abnormally increased excretion of methylmalonate and homocystine was detected by our screening program for metabolic disorders. Amino acid analyses showed that the plasma and urine levels of methionine were very low whereas those of cystathionine were raised. Vitamin B12 deficiency, malabsorption or abnormal cobalamin transport were excluded by a normal serum total cobalamin and normal transcobalamins. These findings suggested a congenital error of cobalamin metabolism. Treatment with vitamin B12 resulted in a biochemical though not a clinical response. Postmortem examination revealed severe vascular lesions with changes in the kidney characteristic of thrombotic microangiopathy supporting a diagnosis of hemolytic-uremic syndrome. It is assumed that the elevated plasma homocysteine induced the vascular lesions by causing detachment of endothelium.
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PMID:Congenital defect in intracellular cobalamin metabolism resulting in homocysteinuria and methylmalonic aciduria. I. Case report and histopathology. 52 29

Most, but not all, megaloblastic anemia is produced by "ineffective erythropoiesis" in the bone marrow due to either folic acid or vitamin B12 deficiency. In folic acid deficiency the cause frequently is inadequate dietary intake, whereas vitamin B12 deficiency is almost always conditioned by some specific type of malabsorption. Anemia with oval macrocytes, few reticulocytes, moderate leukopenia, and thrombocytopenia is typical of both. Aplastic anemia, refractory anemias with cellular marrow, preleukemia, aleukemia, and erythroleukemia may have somewhat similar blood findings but are usually recognizable from bone marrow biopsy. Decreased levels of folate or vitamin B12 are the most reliable criteria of megaloblastic anemia. With these available in advance, therapy with the appropriate vitamin can be begun at once. If serum levels are unavailable or available only in retrospect, initial treatment, especially of severe anemia, should be with both vitamins. Differentiation between folate and vitamin B12 deficiency is important but impossible by blood and bone marrow morphology alone. Thus, if serum levels are unavailable, the distinction must be made, sometimes retrospectively, on the basis of other laboratory examinations, such as gastric analysis, small-bowel x-ray films, and the Schilling test.
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PMID:Megaloblastic anemia. 70 1

A group of subjects had common features of megaloblastic anemia due to vitamin B12 deficiency, normal or high serum folate, and evidence of intestinal malabsorption. They were all former residents of the Caribbean area now living in New York City. Despite similar symptoms and diagnostic studies, two subjects were found to have pernicious anemia and three to have tropical sprue. Achlorhydria, serum anti-intrinsic factor antibody, the severity of small intestinal abnormalities, and posttherapy Schilling tests were helpful differential factors. These subjects illustrate the problems that may be encountered in differentiating tropical sprue and pernicious anemia.
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PMID:Anemia and intestinal dysfunction in former residents of the Caribbean. 83 16

Three cases of congenital selective malabsorption of vitamin B12 (Imerslund-Grasbeck syndrome) are presented. Pathophysiological aspected and clinical symptoms of this disease are discussed together with other megaloblastic anaemias in childhood caused by vitamin B12 deficiency.
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PMID:[Megaloblastic anaemia in childhood due to vitamin B12 deficiency, report of 3 cases of congenital selective vitamin B12 malabsorption (author's tranls)]. 94 59

Because virtually all cases of vitamin B12 deficiency seen in this country are due to malabsorption, the availability of radioactive vitamin B12 for direct measurement of absorption of this essential nutrient has proved to be of great clinical value. These tests are useful not only in demonstrating vitamin B12 malabsorption but also often in defining the pathophysiological mechanism responsible for this abnormality. The urinary excretion test of Schilling remains the most useful test for vitamin B12 absorption. Minor precautions and modifications in technique make the test results more reliable and easier to interpret. The 8-hr plasma test for vitamin B12 absorption can no longer be considered acceptable. Some patients with vitamin B12 malabsorption have results in the normal range when studied by this method. Serum vitamin B12 assays utilizing radioactive vitamin B12 and the isotope dilution principle are not widely used and are useful screening tests. Low normal or borderline results observed in patients with clinical evidence suggestive of vitamin B12 deficiency should be interpreted with caution or confirmed by radioactive vitamin B12 absorption studies. Radioactive vitamin B12 can also be used for rapid, reliable assay of gastric intrinsic factor, antibody to intrinsic factor and unsaturated vitamin B12 serum. Methods using radioactive folate compounds for similar in vivo and in vitro studies are not yet applicable for routine use in nuclear medicine laboratories.
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PMID:Use of radioisotope techniques in the clinical evaluation of patients with megaloblastic anemia. 109 Sep 98

In a material of 14 cases of funicular myelosis the authors demonstrated frequent presence of peripheral signs, psychic changes and rare occurrence of such infrequent syndromes as transverse myelitis, cerebellar syndrome, optic nerve atrophy. Diagnostic difficulties are discussed in cases of pernicious anaemia without blood changes, without gastric achylia, or in patients with vitamin B12 deficiency, malabsorption syndromes and other more infrequent pathological conditions. The importance of such investigations as Schilling's test in atypical cases and the necessity of regular, long-term substitutive treatment with B12 are stressed.
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PMID:[Analysis of cases of funicular myelosis]. 118 51

Intrinsic factor is produced by the gastric parietal cell. Its secretion is stimulated via all pathways known to stimulate gastric acid secretion: histamine, gastrin, and acetylcholine. There is, however, a different mode of secretion for both substances: atropine, vagotomy, and H2 receptor antagonists inhibit both intrinsic factor and acid secretion, but secretin and the hydrogen-potassium ATPase antagonist omeprazole have no effect on intrinsic factor while substantially reducing acid secretion. Cobalamin in food is bound to animal protein. Cobalamin deficiency due to inadequate dietary intake is rarely seen in extreme vegetarians (vegans). In the stomach cobalamin is liberated from its protein binding by peptic digestion and bound to R-proteins. Hypochlorhydria or achlorhydria, whether medically induced or not, may impair cobalamin uptake. The cobalamin-R-protein complex is split by pancreatic enzymes in the duodenum, where cobalamin is bound to intrinsic factor. Pancreatic insufficiency may lead to cobalamin deficiency. Lack of intrinsic factor is the commonest cause of cobalamin deficiency; very rarely, aberrant forms of intrinsic factor are produced, but the clinical syndrome is similar. Gram-negative anaerobe bacteria bind the cobalamin-intrinsic factor complex, and bacterial overgrowth of the small intestine diminishes cobalamin resorption. Parasitic infections with fish tape-worm and Giardia lamblia are also associated with cobalamin malabsorption. The cobalamin-intrinsic factor complex binds to the ileal receptors in the terminal ileum. Cobalamin absorption may be impaired after resection or by diseases affecting more than 50 cm of the terminal ileum, such as Crohn's disease, coeliac disease, tuberculosis, lymphoma or radiation. There is clearly a wide diversity in the aetiology of cobalamin deficiency, which requires a versatile diagnostic approach.
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PMID:Intrinsic factor secretion and cobalamin absorption. Physiology and pathophysiology in the gastrointestinal tract. 177 33


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