Intestinal lymphangiectasia is a very rare disorder that involves blocked or malformed lymphatic vessels in the small intestine. Lymph vessels are little tubes that run throughout the body and have several important functions. They function to drain excess fluids into the blood, to maintain a water-protein balance, to carry disease-fighting white blood cells, and to take up fats from the digestive tract.
In intestinal lymphangiectasia, lymph vessels don’t work, and can no longer drain excess fluids, or absorb fats or proteins properly. The lymphatic fluid instead drains into the small intestine, making it oedematous (swollen). This swelling often backs up even further than the intestine, leading to symptoms like swollen legs. The lymph vessel blockage and swelling cause other symptoms as well, some of which are very serious and potentially life-threatening. Intestinal lymphangiectasia can occur at any age but is most commonly diagnosed in very young children.
The symptoms of intestinal lymphangiectasia include:
The exact cause of intestinal lymphangiectasia is unknown. Still, there are two main mechanisms by which a person develops intestinal lymphangiectasia, and these mechanisms occur in distinct groups. The first mechanism is through malformed lymph vessels within the small intestine. This type of intestinal lymphangiectasia typically exists from birth and is diagnosed before the age of 3 years. People with intestinal lymphangiectasia since birth (congenital) usually have more severe symptoms than those who acquire the disease later in life.
The second mechanism of getting intestinal lymphangiectasia is through blocked, not malformed, lymph vessels. These blockages happen later in life, usually in the 40s-60s. They occur due to serious inflammatory conditions like amyloidosis, cancer, or pericarditis. This form of intestinal lymphangiectasia is acquired, not congenital.
There are no known risk factors of intestinal lymphangiectasia. It is an extremely rare disease, with less than 500 cases of it ever being reported. There is not enough data yet to understand which, if any, risk factors exist.
Intestinal lymphangiectasia is usually diagnosed by endoscopic biopsy. The process begins with a long, tube-like camera (called an endoscope) being placed into the mouth and pushed through the digestive tract. When the endoscope reaches the small intestine, where lots of swelling is happening, the doctor will cut out a small sample (called a biopsy) from the intestine and surrounding areas. The sample will be tested for the activity of certain enzymes, which can help demonstrate the processes of intestinal lymphangiectasia. The biopsy may also be looked at under very high-resolution microscopes to visualize the lymph vessels.
Intestinal lymphangiectasia does not have a cure. It is typically managed with a very strict low-fat diet. This special diet usually requires frequent visits to a doctor as well as to a registered dietician, to make sure the diet is being accurately followed. Less fat being ingested, means less fat for the lymph vessels to absorb. Overall, this reduces the risk that lymphatic vessels get blocked or burst, which would lead to increased swelling.
Alongside a low-fat diet, people with intestinal lymphangiectasia take vitamin supplements of the fat-soluble vitamins, Vitamins A, D, E and K. Without supplementation, they cannot absorb enough of these vitamins. They also take supplements of certain forms of more easily absorbed fats called medium-chain triglycerides. These triglycerides are absorbed directly into the blood and can by-pass the lymph vessels.
Sometimes a surgery called a small-bowel resection is done to treat intestinal lymphangiectasia. It involves cutting out a section of the small intestine, but it is only recommended in specific circumstances.