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

Phosphorylcholine and homocysteine have an important choleretic action and also potentiate exocrine pancreatic secretion by way of stimulation and a more effective preparation of the substrate against attack by lipolytic enzymes. The protection offered by pancreatic enzymes in the correction of the digestive insufficiency in the endoluminal stage is also known. An analysis was therefore made of the action of an association of phosphorylcholine homocysteine and digestive enzymes in cases of exocrine pancreatic insufficiency and primary or secondary malabsorption. This action was evaluated on the basis of the reduction of elimination of steatorrhoea. For this purpose, faecal lipids were determined with the method proposed by van de Kramer et al. The most significant results were obtained in cases where digestive insufficiency was most marked, where correction of the pancreatic enzyme deficiency and improved biliary function were particularly required.
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PMID:[Therapeutic effect of a pharmacologic combination of choleretics and digestive enzymes in exocrine pancreatic insufficiency]. 4 15

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

Subtle cobalamin deficiency states, where low serum cobalamin levels are not accompanied by megaloblastic anemia or malabsorption of free cobalamin, often display metabolic evidence of cellular depletion as shown by the deoxyuridine suppression test. However, the suppression test abnormalities are usually mild and are sometimes atypical; moreover, their response to cobalamin therapy has never been documented. Four patients with this subtle defect, at least three of whom had food-cobalamin malabsorption, were therefore tested before and after cobalamin treatment. Each patient had low serum cobalamin levels but did not have megaloblastic anemia, and all but one had normal serum levels of methylmalonic acid and total homocysteine. Two patients had mildly but typically cobalamin-deficient deoxyuridine suppression test results (baseline values 15.7% and 12.8%; normal less than 8.5%). The other two patients had normal or borderline baseline values (5.4% and 8.9%) that became abnormal on incubation with methyl tetrahydrofolate (16.1% and 12.3%), a pattern previously noted in subtle acquired and hereditary cobalamin deficiencies. After 6 months of cobalamin therapy, the deoxyuridine suppression test abnormalities reversed in all four patients. These findings show that the mild deoxyuridine suppression test stigmata of subtle cobalamin deficiency respond to therapy and thus represent true metabolic deficiency; the unusual abnormality induced in vitro by added methyl tetrahydrofolate responds as well, indicating that it, too, represents metabolic cobalamin deficiency. The findings provide further proof that subtle cobalamin deficiency often exists even when megaloblastic anemia and malabsorption of free cobalamin are lacking, and that the deoxyuridine suppression test can be a reliable tool for its identification.
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PMID:Reversal by cobalamin therapy of minimal defects in the deoxyuridine suppression test in patients without anemia: further evidence for a subtle metabolic cobalamin deficiency. 154 74

Low serum vitamin B12 levels are not uncommon in the elderly. Patients with vitamin B12 deficiency manifest a spectrum of clinical findings. Pernicious anemia and malabsorption syndrome are the usual causes of vitamin B12 deficiency. Pernicious anemia is confirmed by the presence of intrinsic factor blocking antibody or abnormal results on the Schilling test. Patients with neuropsychiatric symptoms of vitamin B12 deficiency may have a normal Schilling test and no evidence of macrocytic anemia. In such patients, vitamin B12 deficiency is confirmed by determining serum levels of homocysteine and methylmalonic acid.
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PMID:The spectrum of vitamin B12 deficiency. 227 93

Cobalamin levels are frequently low in patients with dementia, but it is unclear if they represent definable deficiency and what the mechanisms are. Therefore, patients being evaluated for dementia who had low cobalamin levels but no obvious evidence of deficiency were studied hematologically, neurologically and with metabolic tests and were re-evaluated after cobalamin treatment. Abnormalities suggestive of or diagnostic for deficiency were documented in most of the 16 demented and nondemented patients. Metabolic results: 50% of patients tested had abnormal deoxyuridine suppression and 44% had increased serum methylmalonic acid and/or homocysteine levels; these test results correlated with each other. Neurologic results: 73% of patients had clinical abnormalities, primarily mild neuropathies, not attributable to other causes, 75% had electroencephalographic abnormalities, 77% had abnormal visual evoked potentials and 33% had abnormal somatosensory potentials. Metabolic and neurologic dysfunction were present together or absent together in all but 2 cases. Cobalamin therapy improved 50-100% of the various types of abnormalities, although it did not improve cognitive function in the 13 demented patients. Food-cobalamin malabsorption was found in 60% of the patients. Despite the absence of megaloblastic anemia and rarity of traditional malabsorption of free cobalamin, low cobalamin levels in demented patients frequently represent mild cobalamin deficiency and are often associated with food-cobalamin malabsorption. Perhaps most importantly, this is accompanied not only by metabolic changes but by evidence of mild neurologic dysfunction. Their frequent reversibility by cobalamin confirms that these defects indeed arise from cobalamin deficiency. Although the long-standing dementia does not improve, treating such patients with cobalamin has other concrete benefits.
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PMID:The frequently low cobalamin levels in dementia usually signify treatable metabolic, neurologic and electrophysiologic abnormalities. 778 70

We prospectively studied 41 consecutive elderly patients with serum cobalamin (vitamin B12) levels lower than 125 pmol/l. The protein-bound cobalamin absorption test (PBAT) was performed in 34 of them and in 27 selected elderly control patients. The lower decision limit was 0.18% and an abnormal test was detected in only 9 (26%) of the 34 patients with low serum cobalamin level. When the PBAT was compared to the Schilling (Dicopac method) test, a concordant result was found in 80%. Serum methylmalonic acid and/or total homocysteine concentrations were elevated in 75% (26/35) of the patients with low serum cobalamin levels but also in 30% (5/17) of the control patients. Of the 12 and 9 cobalamin-deficient patients with elevated serum levels of methylmalonic acid and homocysteine, normalization after cobalamin therapy was obtained in 11 and 5 respectively. In conclusion, determination of serum metabolites and their response to cobalamin therapy are a sensitive index of significant cobalamin deficiency and a useful means of distinguishing between cobalamin and folate deficiency. The PBAT offers little advantage over the Schilling test in diagnosing cobalamin malabsorption in elderly patients.
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PMID:Cobalamin absorption and serum homocysteine and methylmalonic acid in elderly subjects with low serum cobalamin. 834 41

Elderly persons are more likely to have low values for serum and erythrocyte folate, and for serum cobalamin. Many of those with low vitamin levels have biochemical abnormalities consistent with true deficiency, including increased formiminoglutamic acid excretion, abnormal marrow deoxyuridine suppression, and raised serum levels of methylmalonic acid and homocysteine. Therapy with the appropriate vitamin reverses the biochemical defect. Despite this, the clinical consequences for most elderly persons are remarkably few. True megaloblastic anaemia is rare, and the small number of therapeutic trials to date have not improved the levels of haemoglobin in the treated subjects, although the mean corpuscular volume has decreased significantly. There has been recent concern that these low blood vitamin levels might be important causes of nervous system damage, but studies specifically of the elderly have not demonstrated overall improvements in neurological function following therapy. Vascular damage from high blood homocysteine levels secondary to cobalamin or folate deficiency remains a potential hazard. Dietary insufficiency, malabsorption of protein-bound vitamin B12 secondary to atrophic gastritis, and defective absorption of folyl polyglutamates seem the likeliest possible causes. Pernicious anaemia, although a common cause of severe megaloblastic anaemia in the elderly, is an infrequent cause for the low cobalamin levels in population studies. Although the benefits are uncertain, the balance of the evidence suggests that one should treat elderly persons with low values of cobalamin or folate. Crystalline vitamin B12 and folic acid are absorbed normally and are therefore suitable for replacement therapy, provided that pernicious anaemia is excluded.
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PMID:Cobalamin and folate deficiency in the elderly. 853 67

We describe a 39-year-old woman with an 8-month history of abdominal pain, diarrhea, and weight loss. Clinical and laboratory evaluation indicated the presence of a malabsorption syndrome. Endoscopy revealed multiple gastric ulcerations and an abnormal "picture" of the duodenal mucosa. At duodenal biopsy, necrosis confined to the distal parts of the enteric villi and a polymorphonuclear leukocyte response were found. Further evaluation revealed intestinal ischemia as a result of mesenteric atherosclerosis. After a revascularization procedure was performed, the symptoms disappeared. The macroscopic and microscopic picture of the bowel normalized. In our search for risk factors of atherosclerosis, we found a substantially increased basal plasma homocysteine concentration. This case suggests that hyperhomocysteinemia may have a causal role in the development of symptomatic, premature atherosclerosis of the mesenteric circulation.
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PMID:Malabsorption syndrome associated with ulceration of the stomach and small bowel caused by chronic intestinal ischemia in a patient with hyperhomocysteinemia. 917 39

We compared the sensitivity and specificity of the two metabolite tests, methylmalonic acid (MMA) and total homocysteine (Hcy) in serum, and serum cobalamin (Cbl) in patients referred to our hospital because of suspected cobalamin deficiency and a serum cobalamin value at the referring unit <200 pmol/L. All 111 patients included were investigated using upper gastrointestinal endoscopy with biopsy specimens taken from the gastric and duodenal mucosa to find a morphological basis for cobalamin malabsorption as well as the Schilling test for the validation of the serum tests. All patients were treated with cobalamin and new blood samples were taken after 4 weeks. We found no difference in sensitivity and specificity between serum MMA, Hcy, and Cbl in identifying patients with and without conditions compatible with cobalamin malabsorption. Elevated serum MMA and Hcy were also found in about 15% of the group of patients with normal Schilling tests and without a morphological basis for cobalamin malabsorption. Moreover, most patients in this group responded with decreased values of the metabolite tests following cobalamin treatment, suggesting that neither elevated metabolites nor a decrease in these values following cobalamin treatment are specific for cobalamin deficiency.
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PMID:Serum methylmalonic acid and total homocysteine in patients with suspected cobalamin deficiency: a clinical study based on gastrointestinal histopathological findings. 939 84

Cobalamin (vitamin B12) deficiency is more common in the elderly than in younger patients. This is because of the increased prevalence of cobalamin malabsorption in this age group, which is mainly caused by (autoimmune) atrophic body gastritis. Cobalamin supplementation is affordable and nontoxic, and it may prevent irreversible neurological damage if started early. Elderly individuals with cobalamin deficiency may present with neuropsychiatric or metabolic deficiencies, without frank macrocytic anaemia. An investigation of symptoms and/or signs includes the diagnosis of deficiency as well as any underlying cause. Deficiency states can still exist even when serum cobalamin levels are higher than the traditional lower reference limit. Cobalamin-responsive elevations of serum methylmalonic acid (MMA) and homocysteine are helpful laboratory tools for the diagnosis. The health-related reference ranges for homocysteine and MMA appear to vary with age and gender. Atrophic body gastritis is indirectly diagnosed by measuring serum levels of gastrin and pepsinogens, and it may cause dietary cobalamin malabsorption despite a normal traditional Schilling's test. The use of gastroscopy may also be considered to diagnose dysplasia, bacterial overgrowth and intestinal villous atrophy in healthy patients with atrophic body gastritis or concomitant iron or folic acid deficiency. Elderly patients respond to cobalamin treatment as fully as younger patients, with complete haematological recovery and complete or good partial resolution of neurological deficits. Chronic dementia responds poorly but should, nevertheless, be treated if there is a metabolic deficiency (as indicated by elevated homocysteine and/or MMA levels). Patients who are at risk from cobalamin deficiency include those with a gastrointestinal predisposition (e.g. atrophic body gastritis or previous partial gastrectomy), autoimmune disorders [type 1 (insulin-dependent) diabetes mellitus and thyroid disorders], those receiving long term therapy with gastric acid inhibitors or biguanides, and those undergoing nitrous oxide anaesthesia. To date, inadequate cobalamin intake has not proven to be a major risk factor. Intervention trials of cobalamin, folic acid and pyridoxine (vitamin B6) in unselected elderly populations are currently under way.
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PMID:Age-related changes in cobalamin (vitamin B12) handling. Implications for therapy. 957 92


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