Bile acid diarrhea, also known as bile acid malabsorption or choleric diarrhea, is a condition where too much bile acid reaches the colon. This excess bile acid causes chronic watery diarrhea that can significantly impact quality of life.
What causes bile acid diarrhea?
Bile acids are produced in the liver to help digest fats. Normally, most bile acids are reabsorbed in the end of the small intestine (terminal ileum). Bile acid diarrhea occurs when there is a problem with this reabsorption, leading to excess bile acids entering the colon.
There are three main causes of bile acid malabsorption:
- Primary bile acid diarrhea – this is an inherited genetic condition that impairs the ileal bile acid transporter responsible for bile acid reabsorption.
- Secondary bile acid diarrhea – this is the most common cause resulting from ileal disease, resection, or inflammation that damages the ability to reabsorb bile acids. Causes include Crohn’s disease, radiation therapy, medications, celiac disease, and chronic infections.
- Idiopathic bile acid diarrhea – this refers to bile acid malabsorption without a known cause.
What are the symptoms of bile acid diarrhea?
The main symptom of bile acid diarrhea is chronic, watery diarrhea. Other symptoms may include:
- Urgent need to have a bowel movement
- Abdominal pain or cramps
- Bloating
- Flatulence
- Fatigue
- Unintended weight loss
The diarrhea often occurs shortly after meals, as the presence of food in the small intestine stimulates the release of bile acids. The diarrhea may wake you up at night and require urgently running to the bathroom.
What does bile acid diarrhea stool look like?
In bile acid diarrhea, the stool is often described as:
- Watery and liquid
- Light brown, yellowish, or greenish color
- Foul smelling
- Floating
- Greasy or frothy appearance
The stool may contain undigested food particles. There is often a large volume of stool passed with bile acid diarrhea bowel movements.
What does bile acid diarrhea pain feel like?
Some common descriptions of abdominal pain with bile acid diarrhea include:
- Cramping pain
- Stabbing pain
- Throbbing pain
- Bloating
- Discomfort
- Constant ache
The abdominal pain may start shortly after eating a meal. It may be episodic, coming and going. The pain may radiate to the back or remain localized to one area of the abdomen. It can range from mild to severe.
What causes the abdominal pain?
The excess bile acids irritate the lining of the colon, resulting in the pain. The bile acids cause the colon to secrete more fluid and contract excessively, leading to cramps. Inflammation from the irritation leads to swelling of the colon tissue, which generates the pain signals.
What tests diagnose bile acid diarrhea?
If bile acid diarrhea is suspected, some tests that may help confirm the diagnosis are:
- Blood tests – help rule out inflammation and infection
- Stool tests – check for blood, fat, bacteria, or parasites
- Hydrogen breath test – measures small intestinal bacterial overgrowth
- Fecal bile acid test – directly measures bile acid levels in stool
- SeHCAT scan – special imaging scan to assess bile acid absorption and transit time
- Colonoscopy – visualizes the colon and takes biopsies looking for inflammation
- CT scan – views anatomy for signs of disease
Response to a bile acid sequestrant medication trial also supports the diagnosis of bile acid diarrhea. The SeHCAT scan is considered the gold standard test.
What conditions are associated with bile acid diarrhea?
Some medical conditions associated with secondary bile acid diarrhea include:
- Crohn’s disease
- Celiac disease
- Ulcerative colitis
- Radiation enteritis
- Small intestine infections
- Small bowel resection
- Cholecystectomy
- Pancreatic disease
Bile acid diarrhea has also been linked with diabetes, hypothyroidism, fibromyalgia, chronic kidney disease, and a variety of medications including metformin and aspirin.
Differential diagnoses
Other conditions that can present similarly with chronic diarrhea include:
- Irritable bowel syndrome
- Microscopic colitis
- Lactose intolerance
- Small intestinal bacterial overgrowth
- Inflammatory bowel disease
- Celiac disease
- Chronic infections
- Medication side effects
What is the treatment for bile acid diarrhea?
Treatment focuses on slowing the transit of bile acids through the colon to allow for increased reabsorption:
- Bile acid sequestrants – medications like cholestyramine and colesevelam bind to bile acids so they are excreted rather than irritate the colon
- Anti-diarrheal agents – medications like loperamide slow intestinal motility giving more time for bile acid absorption
- Probiotics – may promote bile acid metabolism by gut bacteria, reducing free bile acid levels
- Bile acid reuptake inhibitors – experimental agents that increase ileal bile acid transporter activity
- Surgery – ileal resection or bile acid transporter gene therapy may be options in refractory cases
Lifestyle measures like a low fat diet, adequate fluid intake, and exercise can also help improve diarrhea symptoms.
Sample treatment plan
| Medication | Dosage |
|---|---|
| Cholestyramine | 4 grams 1-3 times per day |
| Loperamide | 2-4 mg up to 4 times per day as needed for diarrhea |
| Culturelle Probiotic | 1 capsule daily |
Plus recommend low fat diet, exercise 30 minutes most days, and increase water intake to 8 glasses daily.
Follow up and monitoring
Expect follow up doctor’s visits every 2-4 weeks to monitor symptoms and adjust medications. Repeat lab tests like SeHCAT scan every 6-12 months to assess treatment efficacy. Immediately report any concerning symptoms like blood in stool, fever, dizziness, or swelling.
What is the prognosis for bile acid diarrhea?
With appropriate treatment, many patients see significant improvement or resolution of their diarrhea and pain symptoms. However, bile acid diarrhea is a chronic, relapsing condition. Long term medication use is often required to manage symptoms. Periodic flares are not uncommon.
Studies report the following statistics with treatment:
- 47-89% see improved frequency of bowel movements
- 61-82% experience less fecal urgency and incontinence
- 45-71% have less abdominal pain
The prognosis is best when treatment begins early before complications arise. Poor prognosis is associated with severe malnutrition, weight loss, and reduced quality of life.
Potential complications
Without proper treatment, some potential complications of bile acid diarrhea include:
- Dehydration and electrolyte imbalances
- Malnutrition
- Weight loss
- Fat soluble vitamin deficiencies
- Osteoporosis
- Kidney stones
- Anemia
- Skin irritation
- Depression and anxiety
There is also a theoretical increased risk of colon cancer associated with the chronic inflammation from bile acid exposure.
How is quality of life impacted by bile acid diarrhea?
Bile acid diarrhea can significantly impair quality of life due to:
- Constant need for proximity to a bathroom
- Isolation and embarrassment over symptoms
- Abdominal pain and discomfort
- Sleep disturbances from nighttime diarrhea
- Dietary restrictions to control diarrhea
- Fatigue and reduced energy from dehydration and poor nutrition
- Work or school absenteeism
- Anxiety over unpredictable symptoms
- Depression from chronic illness
- Lower social functioning and intimacy concerns
One study found 74% of patients reported bile acid diarrhea had a major adverse effect on their life. Seeking support groups and therapy can help cope with the psychological aspects of this condition.
Conclusion
In summary, bile acid diarrhea is a debilitating condition characterized by chronic watery diarrhea, abdominal pain, and impaired quality of life. Excess bile acids entering the colon due to defects in ileal reabsorption result in secretory diarrhea. Treatment focuses on slowing intestinal transit time and binding bile acids. While long term medication use is often needed to control symptoms, the prognosis can be good with early effective treatment to prevent complications.