Causes of malabsorption

Malabsorption is insufficient absorption of nutrients. This medical condition is also accompanied by vitamin and mineral deficiency. There is a variety of medical conditions that can lead to malabsorption. They are basically connected with improper functioning of certain parts of the gastrointestinal tract.

Bassen-Kornzweig Syndrome

This syndrome is a hereditary condition and features inappropriate absorption of fats. Without a sufficient amount of fats, the body cannot develop and function properly. This syndrome predominantly affects men, and the actual cause lies in the defect of one or two specific genes. Fats are of great importance for the nervous and muscular systems.

The symptoms of Bassen-Kornzweig Syndrome include inappropriate development, the presence of stool rich in fats, muscular problems such as bad coordination, and weakness of muscles. Additionally, patients may complain about problems with vision and speech.

Biliar Atresia

Biliar atresia is a congenital disease. It features inadequate development of the bile ducts. The consequence of this is accumulation of the bile inside the liver. The patient develops cirrhosis of the liver, and, in the terminal stage of the disease, liver failure.

Bile is essential for the absorption of fats. In people who are suffering from biliary atresia, bile cannot reach the intestines, therefore the fats cannot be properly absorbed.

Celiac Disease

Celiac disease is another medical condition that causes malabsorption. Namely, the patient with celiac disease cannot tolerate gluten, a substance that is present in certain foods. Intake of food rich in gluten leads to the destruction of the intestinal villi, and if large portions of the intestines are damaged absorption of nutrients becomes insufficient.

However, if the disease is found on time just by simple elimination of the food rich in gluten, one can prevent excessive damage to the intestine and reduce the chance of malabsorption.

Intestinal Parasites

Some intestinal parasites, including Giardia lamblia, Necator americanus, and Strongyloides stercoralis, can interfere with digestion of the food. They can either directly 'steal' the food from the host or their presence is what makes absorption difficult.

In many patients suffering from intestinal parasites, malabsorption can be the only symptom of the disease, and it can lead the patient to see his/ her doctor.

Pancreatitis

Destruction of pancreatic tissue, especially if it is caused by autoimmune diseases, as well as acute and chronic inflammation of this gland, in all cases, leads to malabsorption. This can be explained by the fact that the structure of the pancreas has been significantly damaged by inflammation, and the gland cannot produce enzymes necessary for digestion. Malabsorption particularly affects fats since the purpose of pancreatic enzymes is the digestion of these substances.

Small intestine is the part of the gastrointestinal tract where much of the absorption takes place due to its large surface area provided by the numerous microvilli covering intestinal villi and the digestive enzymes on its surface actively secreted to optimize uptake of dietary substances. Adequate absorption takes place when there are mechanically intact digestive organs to produce the necessary enzymes as well as an adequate blood supply, motility, and microflora. Malabsorption develops when malfunction in any of these components leads to failure of absorption of nutrients resulting from a wide variety of causes

Regardless of the cause, malabsorption syndrome refers to the clinical picture comprising diarrhea, steatorrhea, malnutrition, weight loss, abdominal pain, and anemia. Undigested food produces diarrhea, due to its voluminous effect in the bowel lumen. Although all three major nutrients (fat, carbohydrate, and protein) may be malabsorbed, clinical symptoms usually only develop with carbohydrate and fat malabsorption.
The indication for a small intestinal biopsy is usually the work-up of malabsorption, a clinicopathologic picture caused by a number of infectious and noninfectious inflammatory conditions. The biopsy is generally taken through an endoscope, by either forceps or suction, from the duodenum or proximal jejunum. Depending upon the underlying condition, morphological abnormalities are seen in malabsorption range from normal mucosa with increased intraepithelial lymphocytes (gluten-sensitive enteropathy, viral gastroenteritis, food allergies, etc.), villous shortening with crypt hyperplasia (celiac disease (CD), treated CD, tropical sprue, and bacterial overgrowth), to completely flat mucosa (CD, refractory sprue, enteropathy-induced T-cell lymphoma, and autoimmune enteropathy).
Infectious agents that affect gastrointestinal tract can be grouped as food-borne and water-borne bacteria, opportunistic infections (bacterial, fungal, and viral), viral infections (extremely rarely biopsied), and parasitic and helminthic infections. The majority of these infections are, however, self-limited. Although biopsy is more invasive, the use of this procedure allows detection of other causes, including Whipple's disease, other protozoan forms of diarrhea (e.g., cryptosporidiosis, isosporiasis, or cyclosporiasis), Crohn's disease, or lymphoma that may also present as diarrhea and malabsorption.

Small intestinal biopsy is an indispensable component of the diagnostic work-up of patients with malabsorption and/or chronic diarrhea secondary to mucosal damage. Though complete villous flattening usually indicates CD when coexisting crypt hyperplasia is present, there are entities that may cause villous flattening and crypt hyperplasia other than CD. The majority of disorders causing malabsorption, on the other hand, produce mild to moderate villus blunting and crypt hyperplasia without any specific diagnostic feature. Pathologists can also be faced with a patient with malabsorption or chronic diarrhea and a biopsy that appears normal or near-normal architecturally on microscopy.

✓ Fact confirmed: The Malabsorption Syndrome and Its Causes and Consequences Arzu Ensari; 2014 Aug 21.