Malabsorption Syndrome Health Article

Definition

Malabsorption syndrome is an alteration in the ability of the intestine to absorb nutrients adequately into the bloodstream.

Causes and symptoms

Protein, fats, and carbohydrates (macronutrients) normally are absorbed in the small intestine; the small bowel also absorbs about 80% of the 8.4–10.5 qt (8–10 l) of fluid ingested daily. There are many different conditions that affect fluid and nutrient absorption by the intestine. A fault in the digestive process may result from failure of the body to produce the enzymes needed to digest certain foods. Congenital structural defects or diseases of the pancreas, gall bladder, or liver may alter the digestive process. Inflammation, infection, injury, or surgical removal of portions of the intestine may also result in absorption problems; reduced length or surface area of intestine available for fluid and nutrient absorption can result in malabsorption. Radiation therapy may injure the mucosal lining of the intestine, resulting in diarrhea that may not become evident until several years later. The use of some antibiotics can also affect the bacteria that normally live in the intestine and affect intestinal function.

Risk factors for malabsorption syndrome include:

• family history of malabsorption or cystic fibrosis
• use of certain drugs such as mineral oil or other laxatives
• travel to foreign countries, which may introduce parasites into the body
• intestinal surgery
• excess alcohol consumption

Individuals may experience symptoms of malabsorption, the most common of which include:

• anemia, with weakness and fatigue due to inadequate absorption of vitamin B₁₂, iron, and folic acid
• diarrhea (sometimes explosive diarrhea with greasy, foul-smelling stools), steatorrhea (excessive amount of fat in the stool), and abdominal distention with cramps, bloating, and gas due to impaired water and carbohydrate absorption, and irritation from unabsorbed fatty acids
• edema (fluid retention in the body's tissues) due to decreased protein absorption
• malnutrition and weight loss due to decreased fat, carbohydrate, and protein absorption; weight may be 80–90% of usual weight despite increased oral intake of nutrients
• muscle cramping due to decreased vitamin D, calcium, and potassium levels
• muscle wasting and atrophy due to decreased protein absorption and metabolism
• perianal skin burning, itching, or soreness due to frequent loose stools

Irregular heart rhythms may also result from inadequate levels of potassium and other electrolytes. Blood clotting disorders may occur due to a vitamin K deficiency. Children with malabsorption syndrome often exhibit a failure to grow and thrive.

Several disorders can lead to malabsorption syndrome, including cystic fibrosis, chronic pancreatitis, lactose intolerance, and celiac disease (gluten enteropathy, non-tropical sprue).

Tropical sprue is a malabsorptive disorder that is uncommon in the United States, but seen more often in people from the Caribbean, India, or southeast Asia. Although its cause is unknown, the disorder is thought to be related to environmental factors, including infection, intestinal parasites, or possibly the consumption of certain food toxins. Symptoms often include a sore tongue, anemia, weight loss, along with diarrhea and passage of fatty stools.

Celiac disease, also known as non-tropical sprue, gluten enteropathy, or celiac sprue, is an inherited disorder resulting in malabsorption because of an allergic reaction after consumption of a protein called gluten. Gluten is found in wheat, rye, barley, and oats.

Whipple's disease is a relatively rare malabsorptive disorder that affects mostly middle-aged men. The cause of the disorder is possibly related to bacterial infection, resulting in nutritional deficiencies, chronic low-grade fever, diarrhea, joint pain, weight loss, and darkening of the skin's pigmentation. Other organs of the body may be affected, including the brain, heart, lungs, and eyes.

Short bowel syndromes—which may be present at birth (congenital) or the result of surgery—reduce the surface area of the bowel available to absorb nutrients and can also result in malabsorption syndrome.

Bacterial overgrowth that is triggered by intestinal diverticulosis, intestinal disorders, blind loops, fistulas, and strictures may cause malabsorption, resulting in fat malabsorption and flatulence.

Intestinal lymphangiectasia, also called idiopathic hypoproteinemia, is a disorder affecting children and young adults in which the lymph vessels supplying the lining of the small intestine become enlarged. Lymph vessel enlargement may be a birth defect or may have been due to inflammation of the pancreas, called pancreatitis or a condition called constrictive pericarditis, which is characterized by a stiffening of the sac around the heart (constrictive pericarditis). These conditions increase pressure on the lymphatic system. Symptoms of intestinal lymphangiectasia are severe edema, and perhaps nausea, vomiting, mild diarrhea, fatty stools, and abdominal pain. The number of lymphocytes in the blood may decrease. As well, cholesterol and protein levels in the blood are low.