Search:

Malabsorption syndromes

By:

Malabsorption is characterized by suboptimal absorption of fats, fat-soluble and other vitamins, proteins, carbohydrates, electrolytes and minerals, and water. At the ost basic level, it is the result disturbance of at least one of the following normal digestive function.

1. Intraluminal digestion, in which proteins, carbohydrates and fats are broken down into assimilable forms. The process begins in the mouth with saliva , receives a major boost from gagstric peptic digestion and continues in the small intestine assisted by the detergent action of bile salts.
2. Terminal digestion, which involvesthe hydrolysis of carbohydrates and peptides by disaccharidases and peptidases in the brush border of the small intestinal mucosa.
3. Transepithelial transport, in which nutrients, fluid and electrolytes are transported across the epithelium of the small intestine for delivery to the intestinal vasculature. Absorbed fatty acids are coverted to tryglycerides and with cholesterol are assembled into chylomicrons for delivery to the intestinal lymphatic system.

In many malabsorptive disorders, a defect in one pathophysiologic process predominates, but others may contribute. Although many causes of malabsorption can be established clinically diagnosis may require small intestinal mucosal biopsy to exclude celiac sprue satisfactorily.

Clinically the malabsorption syndromes resemble each other more than they differ. The consequences of malabsorption affect many organ systems as follows:

Alimentary tract: Diarrhea (both from nutrient malabsorption and from excessive intestinal secretions, flatus,abdominal pain, weight loss, and mucositis resulting from vitamin deficiencies.

Hematopoietic system :Anemia from iron, pyridoxine, folate or vitamin B12 deficiency and bleeding from vitamin K deficiency.

Musculoskeletal system : Osteopenia and tetany from calcium, magnesium, vitamin D, and protein malabsorption

Endocrine system :Amenorrhea impotence, and infertility from generalized malnutrition and hyperparathyroidism from protracted calcium and vitamin D deficiency

Epidermis : Purpura and petchiae from vitamin K deficiency; edema from protein deficiency; and dermatitis and hyperkeratosis from deficiencies of vitamin A zinc, essential fatty acids, niacin

Nervous system: Peripheral neuropathy from vitamin A and vitamin B12 deficiencies

The passage of abnormally bulky , frothy, greasy, yellow or gray stools (steatorrhea) is a prominent feature of malabsorption, accompanied by weight loss, anorexia , abnormal destention, borborygmi, and muscle wasting. The malabsorptive disorders most commonly encountered in the United States are celiac sprue, pancreatic insufficiency and Crohn disease.

Pancreatic insufficiency, primarily from chronic pancreatitis or cystic fibrosis is a major cause of defective intraluminal digestion. Excessive growth of normal bacteria within the proximal small intestine (bacterial overgrowth ) also impairs intraluminal digestion and can damage mucosal epithelial cells. Immunologic deficiencies, inadequate gastric acidity and interstinal stasis as from surgical alteration of small interstinal anatomy predispose to bacterial overgrowth. Typical features of defective intraluminal digestion are an osmotic diarrhea from undigested nutrients and steatorrhea, which is excess output of undigested fat in stool. The intestinal mucosa in bacterial overgrowth either is normal or is minimally damaged.

Article Source: http://www.diet-article.com

For more information about disease and disorders visit www.medicalhealthcenter.net

Please Rate this Article

Not yet Rated