Chronic diarrhea

A

Exclude iatrogenic problem: medication, surgery

B

Limited screen for organic disease

Suspect IBS

Small bowel: Imaging, biopsy, aspirate

Colonoscopy + biopsy

Blood pr

Features, e.g., stool, suggest malabsorption

Pain aggravated before bm, relieved with bm, sense incomplete evacuation

No blood, features of malabsorption

End

Limited screen for organic disease

Consider functional diarrhea

Limited screen for organic disease

Dietary exclusion, e.g., lactose, sorbitol

Opioid Rx + follow-up

Stool vol, OSM, pH; Laxative screen; Hormonal screen

Low Hb, Alb; abnormal MCV, MCH; excess fat in stool

Low K⁺

Screening tests all normal

Colonoscopy + biopsy

Small bowel: x-ray, biopsy, aspirate; stool 48-h fat

Full gut transit

Stool fat >20 g/d
Pancreatic function

Normal and stool fat <14 g/d

Titrate Rx to speed of transit

Persistent chronic diarrhea