Diarrhea

Background

• >3 BM/day OR abnormally loose stool
• Acute (<2 weeks), persistent (2-4 weeks), or chronic (>4 weeks)
• 95% of acute diarrhea is self-limited & no additional treatment needed
• Most cases of acute diarrhea are due to infections
• Non-infectious etiologies become more common with increasing duration
• Voluminous watery diarrhea more likely disorder of small bowel
• Small volume frequent diarrhea more likely disorder of Colon
• Nocturnal diarrhea suggests an inflammatory or secretory etiology

• Watery diarrhea: viral gastroenteritis (norovirus, rotavirus, enteric adenovirus), C. diff, C. perfringens, S. Aureus, Bacillus cereus, enterotoxigenic E. coli, Cryptosporidium, Listeria, Cyclospora, vibrio cholerae (Giardia is typically more chronic), Tropheryma whipplei
• Inflammatory diarrhea: Salmonella, Campylobacter, Shigella, EHEC, Yersinia, E histolytica, invasive viruses (CMV, HSV), Non-cholera vibrio
• SARS-CoV-2 has been shown to cause GI symptoms such as diarrhea and N/V
  • Medications (see below)
  • Any antibiotic can cause C. diff; the longer the treatment, the more likely
  • Most common to cause C. diff: Clindamycin >Penicillins/Ceph/Fluoroquinolones

Presentation

• Evaluate for red flags (BATS are Vulnerable vampires)
  • Bloody stools, Antibiotics/Recent hospitalization
  • Too many stools: >6 unformed stools/day, Sepsis (Fever)/Severe abdominal pain
  • Vulnerables (Age >70 yr, immunocompromised, IVDU, IBD, pregnant, travel

Evaluation

• • CBC w/ diff, BMP (eval for leukocytosis, AKI, electrolyte abnormalities)
  • C. diff  PCR
  • CRP/ESR (if inflammatory)
  • GIPP  (consider for patients with red flag symptoms (see above))
  • CT A/P if abdominal pain present
  • CT Enterography if concern for IBD
  • Blood Cultures (if febrile)

Management

• Systemic complications (dehydration, AKI, electrolyte abnormalities/acidosis)
  • PO intake (with solute i.e. Gatorade) or IVF if severe/unable to tolerate PO
  • Monitor and replace electrolytes
  • Downsides of abx: can precipitate HUS if 0157:H7, can prolong carrier state if salmonella, can precipitate C. diff
  • Empiric antibiotic therapy ONLY if toxic appearance or high concern for progressive illness/decompensation
    • Ciprofloxacin 500 mg BID or levofloxacin 500 mg daily x 3-5 days
    • Azithromycin 500 mg daily x 3 days
    • Ampicillin + gentamicin used for pregnant women to cover for Listeria
• Symptomatic therapy (Okay to use if C. diff ruled out)
  • Loperamide 4mg x1, 2mg after each loose stool (maximum 16mg/day) for 2 days
  • Lomotil 5mg every 6 hours until control achieved (can alternate with loperamide)
  • Probiotics may be helpful
• C. diff positive (see section below)

Watery

• Motility
  • Hyperthyroidism
  • Diabetes 
  • Amyloidosis
  • Systemic Scleroderma
  • Medications: macrolides, metoclopramide, bisacodyl, senna, pyridostigmine
• Osmotic
  • Lactose Intolerance
  • Bile salt diarrhea
  • Sugar alcohols: Sorbitol, mannitol, xylitol
  • Medications: citrates, lactulose, magnesium-containing antacids, mycophenolate, antibiotics (i.e. ampicillin, clindamycin), methyldopa, quinidine, propranolol, hydralazine, procainamide
• Functional: IBS

Fatty (steatorrhea):​​​​​​​

• Malabsorption
  • Celiac disease
  • Gastric bypass
  • Short bowel syndrome
  • Tropical Sprue
  • Whipple disease
  • Small intestinal bacterial overgrowth (SIBO)
  • Post-infectious malabsorptive diarrhea
  • Maldigestion
  • Pancreatic insufficiency
  • Hepatobiliary disorders

Inflammatory:         

• Diverticulitis
• Ischemic colitis
• Neoplasia
• Radiation colitis
• Arsenic poisoning
• Microscopic colitis
• Invasive infections: bacterial (tuberculosis, yersinosis), viral (CMV, HSV),
• parasites (amebiasis, strongyloidiasis)

• Inflammatory bowel disease (Crohn’s disease, Ulcerative Colitis)

• • Age of onset > 50
  • Rectal bleeding or melena
  • Nocturnal pain or diarrhea
  • Progressive abdominal pain
  • 1^st degree relative with IBD or colorectal cancer Unexplained weight loss, fever, systemic symptoms