Bile Acid Diarrhea: When, Why, How?

March 2, 2024

2,827 3 minutes read

Presented in 13th World Gastroenterology, IBD & Hepatology Conference in Holiday Inn Dubai, Al Barsha, UAE & Virtual from December 15-17, 2023.

Speaker Name: Dr. Cuckoo Choudhary
Biography: MD, FACP, AGAF, Associate Professor of Medicine Division of Gastroenterology and Hepatology, Thomas Jefferson University ( UAS)

Global Journal of Gastroenterology & Hepatology Research [GJGHR]

Bile Acid Diarrhea:

Several diarrheal diseases have a component of bile acid diarrhea
Epidemiology & pathophysiology (why and when)
Clinical presentations (how)
Diagnosis (how)
Management (how)

Synthesis, Secretion, and Enterohepatic Circulation of Bile salts

Synthesis, secretion, Enterohepatic circulation

Bile acids are synthesized from cholesterol in the liver; stored in the gall bladder
Primary bile acids: Chenodeoxycholic acid (CDOA) and Cholic acid (CA)
Released into the small intestines after meals: help in fat digestion
95% of the bile acids that enter the ileum are actively re-absorbed there; of the 5% that go into the colon, most reabsorbed there passively
bile acids are deconjugated and dehydroxylated in the colon to deoxycholic acid and lithocholic acid; Ursodeoxycholic acid also produced in the colon

Epidemiology

25-50% of patients with functional diarrhea (IBS-D) will have a component of bile acid diarrhea (BAD)
4% of our population has IBS
Therefore,1% of our population has bile acid diarrhea
Remember that 1% of population has celiac!!!
- Just like we think about Celiac and have a low threshold to screen for Celiac, we should have a low threshold to think about and screen for BAD

Different Types of BAD: Pathophysiology

Idiopathic Bile Acid Diarrhea

FGF-19 is a protein that functions as a hormone and regulates bile production
Studies from Dr. Walters have shown that the production of FGF-19 in the ileum of patients with idiopathic BAD is reduced
Low FGF-19 stimulates liver to produce bile
When ileal enterocytes absorb bile, they stimulate the receptors in the enterocytes to produce FGF-19
If ileum diseased, absorption decreases, less production of FGF-19, and more production of bile by liver (enterohepatic circulation)

Clinical Symptoms

Increased frequency of liquid, watery stools
Abdominal pain
Urgency
Fecal incontinence

Bile Acid Diarrhea: Quality of Life

Diagnosis

Diagnosis of BAD

The diagnosis is largely clinical for most of us

SehCat retention test
48 hours fecal bile acids
Fasting serum C4
Combination of fasting serum C4 and bile acids in a random stool sample
(which we think will be the future)

SeHCat is an artificial bile acid that has Selenium

Measures the capacity of the ileum to reabsorb the artificial bile acid
Ingested; on the 7th day the retention is measured with a gamma camera
If the retention is < 5%, test positive, and patients thought to have BAD
NA in the US

Measurement of 48 hour fecal bile acids, level of primary bile acids and see of they are 4% or 10% of the total

Diagnosis

A Simpler test for Diagnosis?

C4 measurements vs 48 hours fecal bile acids: validation

Diagnosis

Combining the serum test with the fecal primary bile acids in a random stool sample
Diagnosis of BAD is made if the C4 level > 52.5 ng/ml PLUS the percentage of primary bile acids in the stool sample> 10% of the total fecal bile acid
63 % sensitivity and 90% specificity
Might be the future

Benefits of early Testing in BAD