• BAM is the impaired absorption of bile acids in the small intestine leading to excess bile acids in the colon.

• Bile acids assist in the digestion of lipids and are synthesized in the liver and stored in the gallbladder.

• About 95% of bile acids are normally reabsorbed in the terminal ileum through enterohepatic circulation.

• Excess bile acids enter the colon causing electrolyte and water secretion leading to bile acid diarrhea (BAD).

• Symptoms include chronic diarrhea
• Complications may include steatorrhoea and malabsorption of vitamins A, D, E, and K.

– Type 1 (Ileal Dysfunction): Due to ileal diseases like Crohn’s disease or ileal resection
– Type 2 (Idiopathic BAM): Cause is unknown (primary)
– Type 3 (Secondary BAM): Linked to post-cholecystectomy, post-vagotomy, coeliac disease, bacterial overgrowth, or pancreatic insufficiency
– Type 4 (Excessive Hepatic Synthesis): Often due to excessive bile acid production (e.g., from metformin)

– Ileal dysfunction leads to failure to reabsorb bile acids in the distal ileum
– This results in bile acids spilling into the colon causing symptoms

– Conditions like post-cholecystectomy, post-vagotomy, coeliac disease, bacterial overgrowth, and pancreatic insufficiency
– These conditions affect small intestinal motility and bile acid cycling

– Caused by excessive bile acid synthesis in the liver often triggered by medications like metformin

• Gastrointestinal surgeries
• Inflammatory Bowel Disease (IBD) such as Crohn’s disease
• Coeliac disease
• Radiation therapy in the abdominal area
• Use of bile acid sequestrants

• Impaired reabsorption of bile acids in the ileum

• Osmotic effects
• Altered gut motility
• Activation of colonic receptors

• Irritable Bowel Syndrome (IBS)
• Inflammatory Bowel Disease (IBD)
• Chronic Pancreatitis
• Celiac Disease
• Small Intestinal Bacterial Overgrowth (SIBO)

• Food allergy
• Sugar maldigestion
• Microscopic/lymphocytic colitis
• Small bowel bacterial overgrowth

• Prevalence: Estimated at 1-2% of the population

• Associated Conditions: Functional diarrhea or irritable bowel syndrome with diarrhea (IBS-D)

• Chronic watery diarrhea with significantly increased stool volumes
• Fecal urgency
• Bloating
• Abdominal pain
• Excess gas

• Fat-soluble vitamin deficiencies
• Weight loss

• Typically occurs in individuals aged 30 to 70

• SeHCAT (Selenium-75-Homocholic Acid Taurine) Scan: Nuclear medicine test using a gamma-emitting selenium molecule
• 48-Hour Fecal Bile Acid Measurement: Measures bile acid levels in feces

• SeHCAT Test: Involves scans done 7 days apart
• Abnormal if retention of radiolabeled bile acids is less than 10-15% after seven days

• Total Stool Bile Acid Measurement: Requires 48-hour or longer stool collections
• Serum 7-Alpha-Hydroxy-4-Cholesten-3-One (C4): Increased C4 levels indicate increased bile acid synthesis and fecal loss

• Low 75SeHCAT values correlate more closely with altered bowel habits making it a preferred method for detecting BAM

Dietary modifications:
• Reduce fat intake
• Avoid trigger foods
Medications:
• Bile acid sequestrants (e.g. cholestyramine)
• Bile acid binders: Colestyramine, colestipol, colesevelam

• Low-fat diet
• Oral bile acid binders to control diarrhea and reduce free bile acids’ impact on the colonic mucosa

• Glucocorticoids to induce remission

• Reduce free bile acids preventing their effect on the colonic mucosa
• Colestyramine and colestipol may reduce absorption and serum levels of other drugs (e.g., digoxin, thiazide diuretics)
• Possible impairment of vitamin absorption
• Colesevelam has a higher affinity for bile acids and is effective after cholestyramine treatment failure

• Chronic condition but manageable with treatment
• Not typically life-threatening.

• Many patients respond well to cholestyramine, especially in cases of severe BAM.

• Symptom resolution is possible in some cases with ongoing treatment.

• Constipation, nausea, and abdominal discomfort.

• Malnutrition
• Dehydration
• Weight loss
• Electrolyte imbalances
• Reduced quality of life