What Is Malabsorption?

Malabsorption syndrome is a syndrome caused by the small intestine's absorption of nutrients, which is clinically divided into two types: primary and secondary. Primary malabsorption syndrome is caused by a small defect in the small intestinal mucosa, which affects the absorption of substances and the re-esterification of fatty acids in cells. Secondary malabsorption syndrome is seen in dyspepsia or malabsorption caused by a variety of factors. The main factors are: lack of carmine salt and pancreatic digestive enzymes caused by liver, gallbladder, and pancreatic diseases; major gastric resection, short bowel synthesis Signs, changes in the pH of the digestive tract, and small intestinal or mesenteric diseases can affect the absorption and digestive function of the small intestine; digestive and insufficiency caused by systemic diseases and partial immune deficiency, including glutenic bowel disease and tropical Mouth inflammatory diarrhea.

Malabsorption syndrome

Malabsorption syndrome is a syndrome caused by malabsorption of nutrients in the small intestine for various reasons. The symptoms of malabsorption syndrome in the elderly are often atypical, with abdominal distension, diarrhea, anemia, or bone pain as the main manifestations. The elderly are prone to malabsorption syndrome. The main reason is related to the degenerative changes in the digestive system of the elderly. The most significant changes are the stomach, small intestine and pancreas. When people reach old age, the small intestinal hairs become shorter, the absorption area decreases, the pancreas gradually shrinks, and the interstitial fibrous connective tissue proliferates. These changes have caused the intestinal bacteria to grow excessively, and the gastrointestinal diverticulitis and diverticulosis significantly increased. Insufficient caloric intake and malnutrition can cause or aggravate malabsorption syndrome.

Malabsorption syndrome disease description

Causes of malabsorption syndrome

I. Digestive Disorders

1. Pancreatic enzyme deficiency Pancreatic deficiency: chronic pancreatitis, advanced pancreatic cancer, post-pancreatic resection.

2. Lack of bile salts affects the formation of micelles. (1) Reduced bile salt synthesis: severe chronic hepatocyte disease. (2) Impaired enterohepatic circulation: distal ileal resection, borderline ileitis, biliary obstruction or biliary cirrhosis . (3) Bile salt decomposition: excessive growth of small intestinal bacteria (such as gastric acid deficiency, diabetes, or primary intestinal dyskinesia after gastrectomy). (4) Combination of bile salts and drugs: such as neomycin, calcium carbonate, cholestyramine, colchicine, irritant laxatives, etc.

3. Uneven mixing of food with bile and pancreatic juice. Stomach-jejunum anastomosis was performed after Bias .

4. Intestinal mucosa brush-like enzymes lack lactase, invertase, and enterokinase.

Obstacles to absorption mechanism

1. Insufficient absorption area for large bowel resection, intestinal fistula, gastrointestinal short circuit surgery.

2, mucosal damage celiac disease, tropical steatosis and so on.

3. Impairment of mucosal transport glucose-galactose carrier deficiency, vitamin B12 selective absorption deficiency.

4. Invasive lesions or injuries of the small intestinal wall Whipple disease, lymphoma, radiation enteritis, Crohn's disease, amyloidosis, eosinophilic enteritis, etc.

Third, abnormal transport

1. Lymphatic obstruction Whipple disease, lymphoma, tuberculosis.

2. Mesenteric blood flow disorders Mesenteric arteriosclerosis or arteritis.

4. Carcinoid syndrome, diabetes, adrenal insufficiency.

Pathophysiology of malabsorption syndrome

I. Digestive mechanism disorder: It mainly refers to indigestion of fat, sugar and protein, especially fat indigestion. Pancreatic exocrine insufficiency is one of the more common causes of malabsorption in important senile patients. The malabsorption caused by pancreatic exocrine function by-election is usually milder due to a decrease in daily fecal fat and bile salt concentrations. When bile salts are deficient, it affects the absorption of fat-soluble vitamins. Both acute and chronic liver diseases can be caused by combined bile salt synthesis and Excretory disorders occur with steatosis.

2. Mucosal uptake and intracellular processing obstacles: Absorptive cells with complete structure and function rely on the solubility of the lipid components of the cells to absorb the fat composed of the micellar complex with bile salts into the cells to form chylomicrons. In tropical steatosis, gluten enteropathy and viral enteritis, the absorption cells are damaged, and the less mature crypt cells proliferate to replace the damaged absorption cells. These cells have imperfect structures and functions for processing fat.

3. Lymphatic blood flow transport disorders: Whipple disease, alpha heavy chain disease, ulcerative colitis, small intestinal multiple lymphoma, and small intestinal amyloidosis can cause damage to the intestinal wall, exfoliate or swell and deform the small intestine, resulting in intestinal Lymphocytic disorders and fat malabsorption.

4. Intestinal mucosal abnormalities: Deficiency of intestinal mucosal enzymes such as lactase, invertase, trehalase deficiency, and monosaccharide transport disorders can affect the digestive and absorption processes of the small intestine and cause malabsorption.

V. Excessive reproduction of small intestinal bacteria: bacteria break down nutrients to produce small molecule fatty acids, hydroxyl long chain fatty acids, and decompose bile.

Small intestine incision diagram Salt causes the small intestine to absorb water and electrolyte barriers, and intestinal mucosal cells secrete water and electrolytes into the intestinal cavity, causing diarrhea.

6. Ingestion of substances that are not easily absorbed: When multivalent ions of magnesium, phosphorus, sulfur, mannitol, and lactulose are ingested in large quantities, the intestinal osmotic pressure can be increased and loose stools or even diarrhea can occur.

Diagnostic tests for malabsorption syndrome

I. Diagnosis

A detailed medical history and a serious and determined physical examination, combined with laboratory tests and X-rays, enteroscopy (mucosal biopsy) and special tests can make a diagnosis to understand the organs that cause digestive malabsorption and the possible causes. A detailed medical history is an important clue to the diagnosis of dyspepsia in the elderly. Elderly patients with diabetes should consider diabetic bowel disease. Those who have gastrointestinal surgery are prone to cause overgrowth of blind bacteria. Short bowel syndrome often occurs in patients with a history of small bowel resection. Gastrinoma with persistent ulcers with diarrhea and indigestion should be alert.

Laboratory inspection

1. Blood tests: Anemia is common, mostly large cell anemia, normal cells or confounding anemia, decreased plasma albumin, low potassium, sodium, calcium, phosphorus, magnesium, low cholesterol, increased alkaline phosphatase, and thrombin The original time is extended. In severe cases, serum, folate, carotene, and vitamin B12 levels were also reduced.

2. Fecal fat quantification test: Most patients have steatosis. Fecal fat quantitative test is the only method to confirm the existence of steatosis. Van de Kamer assay is generally used to collect 24h feces from patients with high-fat diets (daily intake of more than 100g of fat) for quantitative analysis. It is normal to have a fat content less than 6g or an absorption rate greater than 90% in 24h, but the fecal fat quantitative test Positive can only indicate the presence of malabsorption syndrome and cannot explain its pathophysiology and make a targeted diagnosis.

3. Determination of serum carotene concentration: The normal value is greater than 100U / dI, which is lower than normal when the malabsorption caused by small intestinal diseases is normal, and it is normal or slightly reduced when pancreatic dyspepsia.

4. Small intestine absorption function test

(1) D-xylose absorption test: Normal people take D-xylose 25 g on an empty stomach, and the amount of D-xylose excretion in urine is 5 g or more. The urine of the small intestine of the proximal intestine or excessive growth of small intestine bacteria can be seen in urine The excretion of sugar is reduced, and the output is 3-4.5g, which is suspected to be abnormal by members; those who are less than 3g can be identified as small intestinal malabsorption. D-xylose is excreted in the urine of elderly patients with renal insufficiency, but the blood concentration is normal, and the normal small intestinal blood concentration> 20mg / dI can be determined by oral administration for 2 hours.

Small intestine indigestion image (2) Vitamin B12 absorption test: firstly intramuscularly inject 1 mg of vitamin B12, and then orally take 122Cog of 57Co or 58Co labeled vitamin B to collect 24h urine, measure urine radioactivity content, and excrete radioactive vitamin B12> 7% in urine within 24h of normal people. Intestinal bacteria multiply excessively, and after ileal malabsorption or removal, urine output decreases.

(3) Breath test: normal people take oral 14C glycinic acid 10mCi, the excretion of fecal 14CO2 is less than 1% of the total in 4h, the excretion is less than 8% in 24h, the small intestine bacteria multiply, return to small excision or dysfunction 14CO2 in the feces, 14CO2 in the lungs, and 14CO2 in the lungs increased significantly, up to 10 times normal. The lactose-H2 breath test can detect lactase deficiency.

Fat digestion process (4) Secretin test: used to detect pancreatic exocrine function, malabsorption caused by pancreatic insufficiency. This test shows abnormalities.

(5) X-ray examination of the gastrointestinal tract: there may be functional changes in the small intestine, dilation of the middle and distal jejunum, inadequate passage of barium, large mucosal wrinkles, smooth bowel wall with a "wax tube" sign, barium segmentation or knotting Block (imprint sign). X-ray examination can also exclude organic diseases such as Crohn's disease of intestinal tuberculosis.

(6) Small enteroscopy: The normal small intestinal mucosa is similar to the duodenal mucosa under the endoscope. The upper jejunal mucosa has a circular wrinkle, and the wrinkles down to the terminal ileum are reduced. The small intestinal mucosa of patients with malabsorption may not be specifically changed, and some may have mucous membranes, stained, low level of annular wrinkles, and reduced number. Histological changes showed atrophy, widening of the villi, different degrees of villus fusion, distortion or even disappearance, deepening of the crypts, proliferation of Brinell's glands, infiltration of a large number of lymphocytes and plasma cells in the lamina propria, and epithelial cells being chaotically filled with confusion , The length varies, the microvilli are in the shape of a measuring cylinder or burn a wide distance, and the microvilli is fused or multiple sticks are in a "bouquet-like" microvilli part or the whole is dissolved.

5. Routine examination of stool: Attention should be paid to traits, red and white cells and undigested food, Sudan III staining for examination of fat globules, quantitative determination of stool fat, aerobic and anaerobic culture of stool; those with anemia on routine blood examination should be bone marrow puncture, Determine the nature and extent of anemia; determine liver function, serum albumin, immunoglobulin, and protein electrophoresis; if necessary, perform a D-xylose test, a fat balance test, and a 14C-glycine-respiratory test.

6. Barium examination in the small intestine: Pay attention to the location and scope of the lesion, whether there is thickening and widening of mucosal folds, barium is distributed in segments, floc or snowflakes, and the emptying time of barium is prolonged.

7. Fiber enteroscopy: if necessary, perform intestinal mucosal biopsy, or use a small intestinal biopsy device to take small intestinal mucosa for histopathological examination and culture of aerobic and anaerobic bacteria.

8. Other tests: if necessary, glucose tolerance test, pancreatic exocrine function test, B-mode ultrasound, plain abdominal film and CT scan to exclude pancreatic malabsorption; do relevant thyroid and adrenal function tests to exclude secondary endocrine Malabsorption due to disease.

Treatment plan for malabsorption syndrome

I. Nutrition support treatment

Choose according to the degree of digestive and absorption disorders and low nutritional status. Daily fecal fat above 30g is severe digestive and absorption disorder, 7-10g is mild, and the middle is moderate. Those with low serum total protein and total cholesterol should be regarded as severely hypotrophic. In mild cases, only diet therapy can improve the condition. When the diet is low-fat (10g / d), high-protein [1.5g / (kg / d)], high-calorie [1003212540kJ (24003000kcal) / d or 167 209kJ (40-50kcal) / (kg / d)], low fiber. Dehydration, electrolyte disturbance, severe anemia and hypoproteinemia should be corrected by intravenous fluid replacement and blood transfusion. Patients with severe digestive and malabsorption problems and intestinal nutritional replenishment should undergo central intravenous nutrition.

Second, cause treatment

1. Lactase deficiency and lactose malabsorption limit lactose-containing foods. Lactase preparations are given at a ratio of 1g to 10g lactose.

2. Pancreatic dyspepsia is an absolute indication for digestive enzymes. The amount of digestive enzymes should be large, 3-5 times the usual amount.

3. For bile acidic diarrhea caused by excision of the terminal ileum, etc., 10-10g / d of cholestyramine can be used.

4. Patients with intestinal lymphangiectasis and fat transport disorders restrict long-chain fatty acid intake and give medium-chain fatty acids.

5, gluten-type bowel disease avoid eating gluten diet, such as barley, wheat, oats and oatmeal, etc., can remove the gluten in flour before eating.

Third, other treatments

1. According to the routine nursing of digestive diseases.

Intestinal digestion 2, eat less residue and low-fat digestible diet; those with celiac disease, avoid wheat, barley, oats and other gluten-containing foods; those with lactase deficiency should not eat dairy foods. In severe cases, intravenous hypernutrition therapy can be given. Fat emulsions, compound amino acids, albumin, etc. can be given, and plasma can be transfused if necessary.

3. Active treatment for the cause: malabsorption caused by Whipple's disease, tropical spruce, and blindfold syndrome, which need to be treated with antibiotics, such as tetracycline, fluazinic acid, and metronidazole. Celiac disease can be treated with hormones. Malabsorption caused by lymphoma and clonal disease can be treated surgically. Pancreatic malabsorption can be treated with pancreatin tablets or animal pancreas drying.

Diagnosis of malabsorption syndrome 4, add a variety of vitamins: such as vitamins A, D, K, B12, and other B vitamins and folic acid. People with iron deficiency anemia can take ferrous sulfate pills or surafil.

5. Symptomatic treatment: those with severe diarrhea should be treated with bismuth hypocarbonate, compound phenethylpiperidine or Yimeng stop, while correcting water and electrolyte balance disorders. If critically ill patients have been ruled out of infection or cancer, they can try glucocorticoid therapy.

6. TCM syndrome differentiation and treatment: those with weak spleen and stomach type are supplemented with spleen and spleen, and Shenlingbaizhu powder is added and subtracted; those with spleen and kidney yang deficiency type are supplemented with spleen and kidney, and supplemented by Sishen Wan or Fuzi Lizhong Decoction; To reconcile the liver and spleen, use Tongxie to add flavor.

Health Tips for Malabsorption Syndrome

1. High protein and high heat energy: high protein, high heat energy, low fat semi-liquid diet or soft food, protein above 100g / d, fat below 40g / d, total heat energy is 10.46MJ (2500kcal), choose food with low fat content and easy digestion, Such as fish, chicken, egg white, tofu, skim milk and so on. Vegetable oil should not be too much. Those with severe diarrhea can give medium chain fatty acids. Those with severe diarrhea can use intravenous high nutrition or elemental diet and homogenized diet to ensure heat energy and positive nitrogen balance.

Malabsorption syndrome 2. Add sufficient vitamins: In addition to food supplements, inject supplements if necessary. Combined with clinical symptoms, focus on supplementing corresponding vitamins, such as vitamin A. Multivitamin B, Vitamin C, Vitamin D and Vitamin K.

3, pay attention to electrolyte balance: especially in severe diarrhea electrolyte supplement is extremely important, early intravenous supplementation. Fresh juice, oil-free broth, mushroom soup, etc. are given in the diet. People with iron deficiency anemia can eat foods rich in iron, such as animal liver, and take iron orally if necessary.

4, a small number of meals: choose soft and easy to digest food, not only ensure adequate nutrition, but will not increase the intestinal burden. Pay attention to the cooking method, it is advisable to cook, braise, burn, steam, etc., to avoid frying, frying, stir frying, etc. to reduce the amount of fat supply.

5, gluten-free diet: celiac disease should strictly and long-term consumption of gluten-free diet, and do not drink beer. Treatment with a gluten-free diet is usually effective for 1 to 2 weeks.