Diarrhea
- In all patients with diarrhea,
- Determine hydration status,
- Treat dehydration appropriately.
- In patients with acute diarrhea, use history to establish the possible etiology (e.g., infectious contacts, travel, recent antibiotic or other medication use, common eating place for multiple ill patients).
- In patients with acute diarrhea who have had recent hospitalization or recent antibiotic use, look for clostridium difficile.
- In patients with acute diarrhea, counsel about the timing of return to work/school (re: the likelihood of infectivity).
- Pursue investigation, in a timely manner, of elderly with unexplained diarrhea, as they are more likely to have pathology.
- In a young person with chronic or recurrent diarrhea, with no red flag symptoms or signs, use established clinical criteria to make a positive diagnosis of irritable bowel syndrome (do not overinvestigate).
- In patients with chronic or recurrent diarrhea, look for both gastro-intestinal and non-gastro-intestinal symptoms and signs suggestive of specific diseases (e.g., inflammatory bowel disease, malabsorption syndromes, and compromised immune system).
General Overview
General Overview
- Acute: 2-14 days of looser and more frequent stools (>3 stools/day or >200g stool/d)
- Parasitic - Giardia, cryptosporidia, cyclospora, isospora, amoebiasis
- Bacteria - Campylobacter, salmonella, shigella, listeria, C diff, S Aureus, Clostridium perfrigens
- Symptoms suggestive of invasive bacterial diarrhea include fever, tenesmus, gross bloody stool
- Viral - Hep A, rotavirus, norovirus
- Travel - ETEC, norovirus, shigella, salmonella, campylobacter, giardia
- Daycare - Campylobacter, cryptosporidia, parvum
- Hospital - C Diff, norovirus, rotavirus (children)
- Chronic: >4 weeks
- Function - IBS (10-20%), overflow constipation, incontinence
- Osmotic - Lactose, sugars (sorbitol, mannitol), laxatives
- Inflammatory - IBD, microscopic/collagenous colitis
- Metabolic - Addison's, hyperthyroid, uremia, cystic fibrosis
- Malabsorption - Pancreatitis, celiac, short bowel syndrome, bacterial overgrowth
- Neoplastic - Colorectal cancer, carcinoid, gastrinoma, medullary thyroid
- Iatrogenic - Drugs, alcohol, caffeine, surgery, radiation, laxatives
- Secretory: Continues despite fasting
- Osmotic: Decreases with fasting (malabsorption, drugs)
- Large Bowel: Small volume, frequent, pus, blood
- Small Bowel: Large volume, infrequent, watery
Risk
Risk
- Travel
- Immunocompromised
- Food outbreaks
- Antibiotics
- Family History
- Laxatives
Red Flags
Red Flags
- Age >50 (think of acute mesenteric ischemia, obstruction, diverticulitis, malignancy)
- Immunocompromised (HIV, steroid)
- Inflammatory features (fever, bloody, mucoid stool)
- N/V, fever, arthritis, skin rash, anorexia
- Night sweats, weight loss
- Nocturnal (pathologic)
- Recent antibiotics (C-diff)
History
History
- Diarrhea onset, duration, severity, frequency, quality (watery, bloody, mucus, purulent, bilious)
- Signs of dehydration (decreased urine output, altered mental status)
- Vomiting (viral or toxin)
- Fever, tenesmus, bloody (invasive bacterial)
- Food/Travel
- Pregnant (12x risk of listeriosis - cold meats, soft cheeses, raw milk)
- Recent sick contacts, antibiotics, medications
- Immunosupression
- Exposures (daycare, fecal-oral sexual contact, hospital admission)
Physical Exam
Physical Exam
- Vitals, orthostatic hypotension, temperature
- Signs of dehydration (decreased urine output, skin turgor)
- Abdominal exam
- Rectal exam (assess stool)
Investigations
Investigations
- Usually not indicated unless severe illness or red flags
- Consider
- CBC, CRP, TSH, Celiac (IgA, anti-TTG)
- FOBT or FIT
- Stool leukocytes/lactoferrin/calprotectin (r/o IBD)
- Stool cultures if leukocytes positive or risk factor/red flag (eg. symptomatic bloody diarrhea)
- C-diff toxins A/B done if unexplained diarrhea after 3d of hospitalization or high risk (eg. antibiotic use)
- Ova and parasites if high-risk (travel to high-risk area, infants in day care, immunosuppresssed, MSM, waterborne outbreak, bloody diarrhea with few fecal leukocytes)
- If available, consider Giardia antigen test or PCR
- C-scope if altered bowel habit +/- rectal bleeding
Treatment
Treatment
- Rehydration (oral if possible)
- Consider reduced oral rehydration solution (ORS): water with salt and glucose
- Early refeeding
- No clear evidence for BRAT diet (banana, rice, applesauce, toast) and avoidance of dairy
- Loperamide/simethicone in non-bloody stool and afebrile
- Consider empiric antibiotics in severe symptomatic bloody diarrhea or immunocompromised
- Fluoroquinolone or Azithromycin (if resistance, eg. from South East Asia)
- Antibiotics effective in shigella, campylobacter, C diff, traveler's diarrhea, protozoal
- Avoid use in toxin (bloody, history of eating seed sprouts, rare beef, outbreak) risk Hemolytic uremic syndrome
Prevention
Prevention
- Hygiene (handwashing, diaper changing, water purification), safe food preparation, clean water
- Vaccine (rotavirus, typhoid fever, cholera)
- No clear evidence for probiotics, zinc supplementation
- Return to school ≥48h last diarrhea/vomiting (NICE)
References:
- AGA 2019. https://www.gastrojournal.org/article/S0016-5085(19)41083-4/fulltext
- British Society of Gastroenterology 2017. https://gut.bmj.com/content/67/8/1380.long
- AAFP 2014. http://www.aafp.org/afp/2014/0201/p180.html
- NICE 2009. https://www.nice.org.uk/guidance/cg84