Causes of Malabsorption Syndromes

Malabsorption is the inadequate absorption of nutrients. It is often accompanied by a variety of conditions including diarrhea, muscle wasting and, in children, failure to thrive. Malabsorption can be caused by a wide spectrum of diseases.

Bassen-Kornzweig syndrome, also known as apolipoprotein B deficiency, is an inherited disease in which the intestine is unable to effectively absorb fats. Without the ability to absorb fats, other parts of the body remain underdeveloped.

The disease, primarily seen in males, is caused by mutations in one of two genes: apolipoprotein B or microsomal triglyceride transfer protein. Without adequate dietary fats, systems in the body, especially the nervous and muscular systems, are not able to develop normally. The symptoms of Bassen-Kornweig syndrome make this easily apparent. Symptoms include:

A diagnosis is made by conducting blood tests and stool sample examinations. Genetic testing may also be performed. The only way to treat this condition is through dietary changes. Certain types of triglycerides are avoided while other types of triglycerides are recommended in the diet. In children with the disease, large doses of dietary supplements are given to treat developmental problems and failure to thrive.

Biliary atresia is a congenital condition (present at birth) where the bile ducts do not properly develop. The bile ducts are necessary for bile to flow from the liver to the intestine, but if the bile ducts are not fully developed, the waste gets backed up in the liver, leading to liver damage, cirrhosis of the liver and eventually liver failure.

Symptoms for biliary atresia develop fairly quickly. The baby may look normal at birth, but by the second or third week, symptoms become very apparent. One of the first symptoms of biliary atresia is jaundice. As more time passes, other symptoms may appear, including:

Biliary atresia is diagnosed by a combination of blood tests, abdominal x-rays and ultrasounds, and a biopsy of the liver. The main treatment option for biliary atresia is a surgical procedure called the Kasai procedure. The Kasai procedure bypasses the improperly developed bile ducts by connecting the liver to the small intestine, allowing bile to leave the liver. The Kasai procedure is most successful if the infant is younger than ten to twelve weeks old. Even with a successful Kasai procedure, damage to the liver may be severe enough that a liver transplant is required.

Celiac disease, otherwise known as nontropical sprue or simply sprue, is an immunologic disease that causes damage to the intestinal villi whenever products containing gluten (found in wheat, barely, rye and oats) are ingested. When damaged, the villi flatten, thus decreasing the overall surface area of the intestine. With the decreased surface area, fewer nutrients are absorbed. If enough damage is done to the villi, malabsorption occurs.

The causes of celiac disease are unknown, although it is known that people with family members affected by celiac disease are at an increased risk of being affected as well. The disease seems to be more common in Caucasians, especially those of European descent, and in women. Celiac disease was once believed to be rare, but recent studies suggest that approximately one out of every 133 Americans has it. Still, only a small percentage of the people with celiac disease have actually been diagnosed.

The symptoms of celiac disease can vary greatly, making it a particularly difficult disease to diagnose. Symptoms include:

If the disease is suspected, diagnosis is made through blood tests and a biopsy of the intestine. Treatment for celiac disease is mainly limited to making changes in diet; most people with celiac disease follow a gluten-free diet, thus preventing further aggravation to the intestines and allowing the villi to heal. Nutritional supplements may be given to correct any nutritional deficiencies, and corticosteroids may be used under certain circumstances.

Intestinal parasites, such as Giardia lamblia, Strongyloides stercoralis, and Necator americanus are known to influence digestion, often resulting in malabsorption. These intestinal parasites typically make their home in the intestines and either disrupt the digestive processes or absorb nutrients meant for the body, thus depriving the body of needed nutrients.

The symptoms for intestinal parasites differ according to the type of parasite and the severity of the infection, but some of the symptoms shared among most intestinal parasites include:

Many people with intestinal parasites are asymptomatic, especially if they only have a mild or moderate infection.

Treatments for intestinal parasites vary according to the parasite, but medications are often used to eradicate the parasites from the body. Supplements may also be given to those suffering from nutritional deficiencies.

The pancreas is a large gland behind the stomach that secretes digestive enzymes to aid in the digestive process. The digestive enzymes are normally inactive until they reach the intestine but if they become active inside the pancreas, the enzymes start "digesting" the organ itself, causing major damage to the gland. This autodigestion of the pancreas is called pancreatitis. Pancreatitis can be classified as either acute or chronic.

How Pancreatitis Causes Malabsorption People suffering from pancreatitis (acute or chronic) begin to lose proper functioning of the pancreas, leading to a reduction in certain digestive enzymes required by the intestine. This results in incomplete digestion of food and inadequate absorption of nutrients.

 

Chronic Pancreatitis: Chronic pancreatitis is long-term damage to the pancreas, resulting in pain and the formation of scar tissue. Excessive, long-term consumption of alcohol is the main cause for chronic pancreatitis, although the use of drugs, cystic fibrosis, high levels of blood calcium, high levels of blood fats and certain autoimmune conditions may also be the culprits.

Symptoms of chronic pancreatitis include:

Treatment for chronic pancreatitis is focused on pain relief. Once the pain is under control, dietary changes are made: A diet high in carbohydrates and low in fat is the most desirable. Severe cases of chronic pancreatitis may warrant surgery to relieve pain.

Shwachman-Diamond syndrome (SDS) is a rare inherited disease involving the pancreas, the bone marrow and the skeleton. It is one of the second most common causes of pancreatic insufficiency in children.

 

SDS and Cystic Fibrosis Cystic fibrosis and SDS are often mistaken for one another. One of the major differences between the two is that children with SDS test normal for the sweat test.

 

People with SDS often have inadequate absorption of nutrients because of the incomplete digestion of the food. The incomplete digestion is due to improperly functioning pancreatic cells, which are responsible for the production of digestive enzymes.

The disease is inherited, so it is evident almost from birth. Infants with SDS often have diarrhea (and smelly, greasy stools), and failure to thrive is a problem. People with SDS often have decreased blood cell counts due to dysfunctions of the bone marrow, and they may also develop abnormalities in the bone.

Diagnosis is made through a series of blood tests, stool sample examinations and skeletal surveys. SDS is normally detected soon after birth because parents are concerned about their baby's failure to thrive.

Treatment depends on a variety of factors, including the extent of the disease and the child's health, but usually involves pancreatic enzyme replacement, where supplemental digestive enzymes are given to the child to aid in digestion. Dietary changes and nutritional supplements may be necessary to treat the child's failure to thrive. Infections as a result of a low blood cell count are usually treated with antibiotics.

Resources

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Centers for Disease Control and Prevention (CDC). (updated 1999). Fact sheet: Hookworm infection.

Children's Hospital Boston. (2001). Shwachman-Diamond syndrome.

Cystic Fibrosis Foundation. (updated 2005). What is CF?

Khoury, G. (updatd 2005). Pancreatitis.

National Digestive Diseases Information Clearinghouse. (updated 2004). Pancreatitis [NIH Publication No. 04-1596].

National Library of Medicine. (updated 2003). Bassen-Kornzweig syndrome. MedlinePlus Medical Encyclopedia.

National Library of Medicine. (updated 2004). Biliary atresia. MedlinePlus Medical Encyclopedia.

National Library of Medicine. (updated 2003). Celiac disease—Sprue. MedlinePlus Medical Encyclopedia.

National Library of Medicine. (updated 2004). Malabsorption. MedlinePlus Medical Encyclopedia.

Ohio State University College of Biological Sciences. (nd). Strongyloides stercoralis.

Schwarz, S. (updated 2004). Biliary atresia.

Shwachman-Diamond Syndrome Foundation. (updated 2005). Disease information.

Spoto-Cannons, A.C. (updated 2002). Shwachman-Diamond syndrome.