CONDITIONS OF MALABSORPTION
Malabsorption is the inability of the digestive system to absorbone or more of the major vitamins (especially vitamin B12), min-erals (ie, iron and calcium), and nutrients (ie, carbohydrates, fats, and proteins). Interruptions in the complex digestive process may occur anywhere in the digestive system and cause decreased ab-sorption. Diseases of the small intestine are the most common cause of malabsorption.
The conditions that cause malabsorption can be grouped into the following categories:
• Mucosal (transport) disorders causing generalized mal-absorption (eg, celiac sprue, regional enteritis, radiation enteritis)
• Infectious diseases causing generalized malabsorption (eg, small bowel bacterial overgrowth, tropical sprue, Whipple’s disease)
• Luminal problems causing malabsorption (eg, bile acid defi-ciency, Zollinger-Ellison syndrome, pancreatic insufficiency)
• Postoperative malabsorption (eg, after gastric or intestinal resection)
• Disorders that cause malabsorption of specific nutrients (eg, disaccharidase deficiency leading to lactose intolerance)
Table 38-2 lists the clinical and pathologic aspects of malabsorptive diseases.
The hallmarks of malabsorption syndrome from any cause are di-arrhea or frequent, loose, bulky, foul-smelling stools that have in-creased fat content and are often grayish. Patients often have associated abdominal distention, pain, increased flatus, weakness, weight loss, and a decreased sense of well-being. The chief result of malabsorption is malnutrition, manifested by weight loss and other signs of vitamin and mineral deficiency (eg, easy bruising, osteoporosis, anemia). Patients with a malabsorption syndrome, if untreated, become weak and emaciated because of starvation and dehydration. Failure to absorb the fat-soluble vitamins A, D, and K causes a corresponding avitaminosis.
Several diagnostic tests may be prescribed, including stool studies for quantitative and qualitative fat analysis, lactose tolerance tests, D-xylose absorption tests, and Schilling tests. The hydrogen breath test that is used to evaluate carbohydrate absorption is performed if carbohydrate malabsorption is suspected. En-doscopy with biopsy of the mucosa is the best diagnostic tool. Biopsy of the small intestine is performed to assay enzyme activity or to identify infection or destruction of mucosa. Ultrasound studies, CT scans, and x-ray findings can reveal pancreatic or intestinal tumors that may be the cause. A complete blood cell count is used to detect anemia. Pancreatic function tests can assist in the diagnosis of specific disorders.
Intervention is aimed at avoiding dietary substances that ag-gravate malabsorption and at supplementing nutrients that have been lost. Common supplements are water-soluble vitamins (eg, B12, folic acid), fat-soluble vitamins (ie, A, D, and K), and minerals (eg, calcium, iron). Primary disease states may be man-aged surgically or nonsurgically. Dietary therapy is aimed at re-ducing gluten intake in patients with celiac sprue. Folic acid supplements are prescribed for patients with tropical sprue. Anti-biotics (eg, tetracycline, ampicillin) are sometimes needed in the treatment of tropical sprue and bacterial overgrowth syndromes. Antidiarrheal agents may be used to decrease intestinal spasms. Parenteral fluids may be necessary to treat dehydration.
The nurse provides patient and family education regarding diet and the use of nutritional supplements (Chart 38-2). It is impor-tant to monitor patients with diarrhea for fluid and electrolyte imbalances. The nurse conducts ongoing assessments to deter-mine if the clinical manifestations related to the nutritional deficits have abated. Patient education includes information about the risk of osteoporosis related to malabsorption of calcium.
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