What causes bile acid malabsorption?

What causes bile acid malabsorption?

Bile acid malabsorption is also known as bile acid diarrhea. It can result in many intestine-related problems, including chronic cases of diarrhea. It occurs due to the malabsorption of bile caused by gastrointestinal disease or it can be a primary disorder in itself, associated with excessive bile acid production.

What is bile acid malabsorption?

Bile acid is needed by the digestive system to better metabolize and absorb fat consumed in the diet. They are made in the liver and then released into the gallbladder found near the upper intestine. When food is consumed that has a high-fat content, it stimulates the gallbladder to excrete bile acid into the small intestine. Here it begins to break down digested food into their molecular form for optimal digestion. Excess bile acid is then reabsorbed and is stored in the gallbladder, where the process repeats when eating another meal high in fat.

The problem occurs when bile acid is not reabsorbed during the last part of food content break down. This might occur due to disease or malfunction of the area of the small intestine responsible for reabsorption. This leads to an excessive amount of bile acid in the intestinal tract not being reabsorbed, and in effect, it causes excess amounts of fluid to be pumped into the colon, causing diarrhea.

This often means that those who have this condition will need to find a bathroom urgently during times of bile acid malabsorption. Diarrhea could appear pale and greasy as a result, owing to the excess amounts of bile acid in the intestines. Malabsorption will also lead to cramp-like pains in the abdomen.

Causes and symptoms of bile acid diarrhea

Many diseases of the gut can cause bile acid malabsorption, especially diseases that affect the last part of the small intestine—the terminal ileum. Other conditions include surgical removal of the gallbladder, coeliac disease, diseases affecting the pancreas, and side effects of radiotherapy for cancer treatment. Bile acid malabsorption may also be caused by a number of medications, once of which is metformin, a common medication for the treatment of type 2 diabetes.

Here’s a breakdown of bile acid classifications:

Type 1: Bile acid malabsorption, secondary to ileal resection or ileal inflammation:

  • Crohn’s disease, ileal resections

Type 2: Idiopathic or primary bile acid malabsorption (cause unknown):

Type 3: Secondary to various gastrointestinal diseases:

  • Cholecystectomy, small intestinal bacterial overgrowth, post radiation, coeliac disease, chronic pancreatitis

Symptoms of bile acid malabsorption may include:

  • Watery diarrhea
  • Urgency to use the bathroom due to diarrhea
  • Diarrhea occurring in the middle of the night
  • Incidents of soiling the pants
  • Bloating
  • Abdominal cramps
  • Vitamin malabsorption—vitamin B12

Diagnosing bile acid malabsorption

An ideal test for bile acid malabsorption is called 75selenium homocholic acid taurine test (75SeHCAT). This is a nuclear medicine test whereby the patient swallows a capsule and then undergoes full body scanning, with a repeat scan done seven days later. This test is used to assess the ability of the small intestine to retain bile acid, with a retention rate of less than 15 percent considered positive for bile acid malabsorption.

Unfortunately, this test is not available in the United States, and doctors have to rely on the use of medication thought to be effective and observing the results. Another method for diagnosis requires a 24-hour stool collection. Though this method can provide a definite diagnosis of bile acid malabsorption, it is rarely done.

Bile acid malabsorption treatment

If the particular case of bile acid malabsorption has an identifiable cause, treatment is focused on treating that illness, with relief of the symptoms of bile acid malabsorption expected to resolve afterward. If no such underlying cause is found, the use of bile acid sequestrant can help reduce the about of bile left in the gut, reducing symptoms. Such medications include cholestyramine (Questran), colesevelam (WelChol) and colestipol (Colestid). These medications require a prescription and may lead to side effects such as abdominal pain and bloating.

The use of probiotics may help with digestive problems associated with an imbalance of intestinal bacteria. They may help with gas, bloating, and diarrhea in certain cases. Probiotics are considered safe and may be a good way to support the digestive process and correct problems with bile acid malabsorption.

Related: Throwing up bile: Causes and treatments



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