Acute Diarrhea in Adults

Background

• Acute diarrhea in adults is defined as 3 or more loose or watery stools in a 24 hour period. Diarrhea that lasts < 14 days is termed acute, 14-30 days persistent, and > 30 days as chronic.
• The initial onset of a chronic diarrheal illness may present as a complaint of acute diarrhea.
• Common causes of acute diarrhea in adults include:
  • infection (the most common) due to:
    • viral pathogens such as norovirus, are the most common cause and estimated to account for at least 50% of acute diarrheal illnesses in the United States
    • bacterial pathogens such as Salmonella, Shigella, Campylobacter, enterotoxigenic Escherichia coli (ETEC), enterohemorrhagic Escherichia coli (with Shiga toxin), and Clostridioides difficile
    • parasites such as Giardia lamblia and Entamoeba histolytica
  • noninfectious medical conditions such as lactose or other food intolerances, irritable bowel syndrome, the initial presentation of inflammatory bowel disease, or other gastrointestinal or endocrine conditions.
  • medications such as antibiotics, selective serotonin receptor inhibitors, and colchicine are common, but consider any new medication as a potential cause.
• Risk factors to ask about include recent potential exposure to infectious agents through personal contacts (particularly exposure to daycare, hospital, or long term care settings), travel, tainted food consumption, and antibiotic use.
• Most courses of acute diarrhea are self-limited; prognosis is excellent once complications such as dehydration/volume depletionand electrolyte disturbances are corrected, and a course of antimicrobials is completed in patients if indicated.

Evaluation

• Evaluate all patients with acute diarrhea for dehydration (Strong recommendation).
• Conduct detailed symptom history and physical exam to assess severity and to assist etiological investigation if necessary.
• Evaluate patient's exposure history to identify potential causative pathogens.
• If symptoms are mild and/or improving, etiologic investigation is generally not necessary in immunocompetent adults. Factors suggesting consideration for etiologic investigation include:
  • potential for infectious outbreak, such as patients who are food handlers, exposed to a nursing home/daycare setting, or there are other reasons to suspect an outbreak
  • any of the following symptoms:
    • duration > 7 days
    • fever
    • blood or pus in stool
    • severe abdominal cramping or tenderness
    • signs of sepsis or severe dehydration
    • persistent abdominal pain
    • large volume rice-water stools
  • certain epidemiologic risk factors
    • fever and risk factors for yersiniosis, such as
      • consumption of raw or undercooked pork or poultry
      • consumption of unpasteurized dairy products
      • exposure to animal feces
    • risk factors for Vibrio infection
      • travel to cholera-endemic region 3 days prior to diarrhea onset
      • exposure to salty or brackish waters
      • consumption of raw or undercooked shellfish
• If etiologic investigation is warranted, consider specific diagnostic procedures for laboratory evaluation based on suspected enteropathogens:
  • Conduct stool studies based on clinical presentation (Strong recommendation).
• Consider additional testing such as serologic testing, computed tomography, magnetic resonance enterography, sigmoidoscopy, or colonoscopy in severe illness or if causes other than infectious gastroenteritis are suspected (Weak recommendation).

Management

• Start rehydration therapy if dehydration is suspected (Strong recommendation).
  • Oral route is preferred.
  • Most healthy adults with acute diarrhea can rehydrate by consuming water, juice, broth based soups, or sports drinks.
  • Use oral rehydration solution (ORS) (2-4 L/day) as first-line therapy for mild-to-moderate dehydration in adults with acute diarrhea from any cause, but particularly in people who are vulnerable such as older patients or those with severe symptoms. (Strong recommendation)
  • If there is severe dehydration, shock, or altered mental status and oral route is not possible, consider IV rehydration such as with Ringer lactate (Strong recommendation).
• After dehydration is addressed, resume usual diet (Strong recommendation).
  • There is limited evidence to support avoiding solid food or dairy or to restrict diet to bananas, rice, applesauce, and toast (BRAT diet).
• If symptomatic treatment is indicated, antimotility or antiperistaltic agents might reduce stool volume and frequency but are contraindicated if bloody stools, fever, or abdominal pain are present.
  • Common therapies include loperamide monotherapy, loperamide-simethicone combination, or racecadotril (not available in United States).
  • Consider loperamide in immunocompetent adults with acute watery diarrhea or as adjunctive therapy to antibiotics in treatment of traveler's diarrhea (Weak recommendation).
  • For patients with bloody stool, fever, or other contraindications to loperamide, consider bismuth subsalicylate (such as "Pepto-Bismol"), but be aware of contraindications, including concurrent use of anticoagulants or other medications, pregnancy, advanced HIV infection, and other factors.
  • For patients with advanced HIV and acute diarrhea, consider crofelemer (Fulyzaq), a chloride-channel blocker.
• Consider antimicrobial medications not routine, but only for specific circumstances.
  • Empiric use is not recommended unless there is
    • moderate to severe traveler's diarrhea (Weak recommendation); consider a quinolone or azithromycin
    • presumptive Shigella infection (fever documented in a medical setting, abdominal pain, and bloody diarrhea) (Strong recommendation)
    • immunocompromised patient with severe illness and bloody diarrhea (Strong recommendation)
  • Patients who are improving but have an infection such as Salmonella or Campylobacter usually do not need antibiotics.
  • Inappropriate antibiotic use may lead to:
    • antimicrobial resistance of bacterial pathogens
    • Clostridioides difficile infection
    • prolonged carrier state (such as with delayed excretion of Salmonella infection)
    • disturbance of healthy GI microbiome
    • increased risk of hemolytic-uremic syndrome (HUS) in patients with Shiga toxin-producing Escherichia coli; see Hemolytic-uremic Syndrome (HUS) for additional information.
  • When patients have an etiology identified, adjust antimicrobial management accordingly (Strong recommendation).
  • Numerous regimens are available for specific infections.