II. Definitions
-
Gastroenteritis
- Inflammation of the Gastrointestinal Tract (Stomache and Small Intestine)
- Typical presentation is Vomiting followed by Diarrhea
- Most typically secondary to Viral Gastroenteritis
- Can also be caused by Bacteria with ingestion of preformed toxin
- Diarrhea
- Frequent liquid, loose or watery stools
- Adults: >200 g/day of stool (at least 3 Bowel Movements daily)
- Children: >20 g/kg/day of stool
- Timing
- Acute Diarrhea: Duration <2 weeks
- Considered prolonged when duration >7 days
- Persistent Diarrhea: Duration 2 to 4 weeks
- Chronic Diarrhea: Duration >4 weeks
- Acute Diarrhea: Duration <2 weeks
- Frequent liquid, loose or watery stools
III. Epidemiology
- Foodbourne Diarrhea cases: 48 million/year U.S.
- As many as 179 million outpatient visits in the U.S. per year
- Hospitalizations: 128,000 to 500,000/year U.S
- Deaths: 3000 to 5000 per year U.S. (2.5 Million/year worldwide)
IV. Pathophysiology
-
Small Intestine secretes and reabsorbs 10 liters/day
- Extrusion of Chloride from villus crypt cell (cAMP)
- Absorption at villus tip
- Diarrhea classified as one of 3 types
- Watery Diarrhea
- Secretory Diarrhea
- Stool Sodium high (60-120 meq/L)
- Hypersecretion by intestinal crypts
- Osmotic Diarrhea (osmotic loss of free water)
- Stool Sodium low (30-40 meq/L)
- Ingestion of non-digestable agents that draw water from the bowel wall
- Secretory Diarrhea
- Inflammatory Diarrhea (Dysentery)
- Severe Diarrhea with pus or blood present in the stool
- Associated with fever, Abdominal Pain and tenesmus
- Fatty Diarrhea (Malabsorption)
- See Chronic Diarrhea
- Large greasy, frothy pale stools with foul odor
- Watery Diarrhea
- Serum Electrolyte loss
- Serum Bicarbonate loss
- Serum Potassium loss
V. Causes: Acute Vomiting (Gastroenteritis)
- See Vomiting Causes
- See Foodborne Illness
- Severe Emergency Department cases in adults
VI. Causes: Acute Diarrhea
- See Chronic Diarrhea for systemic medical condition causes of Diarrhea
- See Drug-Induced Diarrhea
- Noninfectious Causes
- See Osmotic Diarrhea
- See Secretory Diarrhea
- Common Causes
- Partial Intestinal Obstruction
- Toxic Ingestions
- Endocrine Causes (Thyroid disease)
- Inflammatory Bowel Disease (and other inflammatory and Allergic Conditions)
- Crohn Disease
- Ulcerative Colitis
- Radiation Enteritis
- Drug Withdrawal (e.g. Opioid Withdrawal)
- Cholinergic Toxicity (e.g. Organophosphate Poisoning)
- Mesenteric Ischemia
- Extra-intestinal and non-Gastroenteritis infections
-
Infectious Diarrhea Causes
- See Infectious Diarrhea Causes
- See Foodborne Illness
- See Waterborne Illness
- Viruses (30-40% of episodes) - Non-Inflammatory Diarrhea
-
Bacteria and Parasites (20-30% of episodes)
- Inflammatory Diarrhea from Bacteria and Parasites (Dysentery)
- Campylobacter jejuni (most common Bacteria)
- Salmonella
- Shigella
- Shiga-toxin producing E. coli (e.g. E. coli 0157:H7, Enterohemorrhagic E. coli)
- Causes 30% of infectious bloody Diarrhea
- Clostridioides difficile
- Entamoeba histolytica
- Yersinia
- Non-Inflammatory Diarrhea from Bacteria and Parasites
- Inflammatory Diarrhea from Bacteria and Parasites (Dysentery)
VII. Risk Factors
- See Chronic Diarrhea for systemic medical condition causes of Diarrhea
- See Infectious Diarrhea Causes
- Recent travel to endemic area
- See Traveler's Diarrhea
- Travel to a developing area is associated with a 25% chance of developing Diarrhea
- Those with Diarrhea in a developing area have an 80% chance of Bacterial Diarrhea
- Food associated illness
- See Foodborne Illness
- Associated with raw meats, poultry, fish, seafood, milk, rice
- Wilderness travel (or in developing country)
- See Waterborne Illness
- Hiking in wilderness areas (especially drinking from mountain streams)
- Consider Giardia, Entamoeba histolytica, Cryptospordium
- Day care exposure
- Consider Rotavirus, Cryptosporidium, Giardia, Shigella
- High-risk sexual behavior
- See Infectious Diarrhea Causes
- Fecal-oral sexual contact: Shigella, Salmonella, Campylobacter, Protozoa
- Receptive anal intercourse: Herpes Simplex Virus, Chlamydia, Gonorrhea, Syphilis
-
Antibiotic use within 6 months or recent hospitalizations
- See Clostridium difficile
- C. Difficile Incidence in unexplained Diarrhea after 3 or more day hospitalization: 15-20%
- Risk of infection after Antibiotics in first month (7-10 fold increased risk)
- Risk persists more than 3 months after Antibiotics (2-3 fold increased risk)
- Consider Klebsiella oxytoca (uncommon)
- Like Clostridium difficile, causes Antibiotic-Associated Diarrhea, that may be hemorrhagic
- Improves after stopping Antibiotics and NSAIDs
-
Immunosuppression (e.g. HIV Infection, Chemotherapy, longterm Corticosteroids, Immunoglobulin A Deficiency)
- See Diarrhea in HIV
- Consider Cryptosporidium, Microsporida, Isospora, Cytomegalovirus
- Consider Mycobacterium Avium Intracellulare complex, Listeria monocytogenes
VIII. History: Diarrhea
- See Vomiting
-
Stool size
- Frequent small volume stools
- Frequent large volume stools
-
Stool consistency
- Rice-water stools (Vibrio Cholerae)
- Provocative agents
- Foods
- Milk
- Sorbitol
- New medications (see Medication-Induced Diarrhea)
-
Inflammatory Diarrhea associated findings
- Blood or mucous present in stool
- Fever (typically absent in Shiga-toxin producing E. coli 0157:H7)
- Abdominal Pain
- Tenesmus (or Rectal Pain or Proctitis)
- Other associated findings
- Paresthesias (consider Neurotoxin such as Ciquatera toxin)
- Acute symptoms in multiple people with same food exposure (Preformed toxins)
- See Foodborne Illness
- Symptom onset within 6 hours (presents with Vomiting)
- Staphylococcus aureus (often from cold mayonnaise-based salads)
- Bacillus Cereus (meats, rice)
- Symptom onset within 8-16 hours (presents with Diarrhea)
- Clostridium perfringens (Cooked meats)
IX. Symptoms
-
Fever
- Campylobacter
- Salmonella typhi
- Shigella
- Yersinia
- May also occur with Clostridium difficile and Entamoeba histolytica
-
Abdominal Pain
- Campylobacter
- Salmonella typhi
- Shigella
- Shiga-toxin producing E. coli (e.g. E. coli 0157:H7, Enterohemorrhagic E. coli)
- Yersinia
- Giardia
- Norovirus
- May also occur with Clostridium difficile and Entamoeba histolytica
-
Nausea or Vomiting
- Shigella
- Norovirus
- Also occur with Campylobacter, Salmonella, E. coli 0157:H7, Yersinia, Cryptosporidium, Cyclospora, Giardia
- Bloody stool
- Shiga-toxin producing E. coli (e.g. E. coli 0157:H7, Enterohemorrhagic E. coli)
- Causes 30% of infectious bloody Diarrhea
- May also occur with Campylobacter, Clostridium difficile, Salmonella, Shigella, Yersinia
- Shiga-toxin producing E. coli (e.g. E. coli 0157:H7, Enterohemorrhagic E. coli)
X. Exam
- See Vomiting
- Evaluate for signs of Dehydration
- Tachycardia
- Dry mucous membranes
- Decreased Urine Output
- Altered Level of Consciousness
- Capillary Refill
- Poor Skin Turgor
- Sunken Fontanelles (infants)
-
Eye Exam
-
Episcleritis
- Consider Inflammatory Bowel Disease such as Reiters Syndrome
-
Episcleritis
- Thyroid exam
- Skin Exam
- Abdominal exam
- Benign Abdomen despite severe pain
- Consider Mesenteric Ischemia (especially if grossly bloody stool)
- Bowel sounds
- Hyperactive bowel sounds
- Typical in Diarrheal illness
- Hypoactive bowel sounds
- Hyperactive bowel sounds
- Benign Abdomen despite severe pain
-
Rectal Exam
-
Anal Fissures
- Consider Inflammatory Bowel Disease
- Bloody stool (occult or gross)
- Consistent with Acute Inflammatory Diarrhea
- Concurrent fever, Abdominal Pain, tenesmus also suggest Acute Inflammatory Diarrhea
- Consider Inflammatory Bowel Disease
- Consider Mesenteric Ischemia
-
Anal Fissures
XI. Labs
- See specific tests for indications
- Precautions
- Labs are expensive and do not alter management in most cases (in the United States)
- Directed history and exam are most useful
-
General indications for lab testing
- Dysentery (Bloody Diarrhea, Fever, Abdominal Pain, Tenesmus)
- Sepsis
- Persistently more than 6 stools daily
- More than 1 week of symptoms without improvement
- Hospital admission for Dehydration
- History suggestive of specific Parasite or pathogen
- Recent travel with moderate to severe Diarrhea (esp. with fever)
- Public health implications
- Food handlers, healthcare workers or childcare workers
- Nursing Home residents
- High risk patient
- Age >65 years old
- Infant <12 months
- Pregnancy
- Immunocompromised state
- Men who have Sex with Men
- Labs performed as indicated
- Enteric Pathogens Nucleic Acid Test Panels (PCR, NAAT)
- May include Campylobacter, Salmonella, Shigella, Vibrio, Yersina, Norovirus, Rotavirus, Shiga-Toxin
- Some panels (e.g. Biofire FilmArray) include C. Diff, as well as >20 other Bacteria, Parasites and viruses
- Stool Antigens
- Giardia lambliaAntigen
- Indicated for Diarrhea >7 days and >10 stools/day
- CryptosporidiumAntigen
- Immunocompromised patients
- Clostridium difficile Toxin
- Follows hospitalization for >3 days or
- Antibiotic use within prior 3 months
- RotavirusAntigen
- Indicated for defining local outbreak
- Giardia lambliaAntigen
- Medication levels
- Theophylline level
- Lithium level
- Pregnancy Test
- Consider in all women of reproductive age with significant gastrointestinal symptoms
- Serum Electrolytes (basic metabolic panel)
- Normal in 99% of young, healthy adults with Acute Gastroenteritis in the first 24 hours
- Indications
- Prolonged Diarrhea
- Dehydration requiring IV fluids
- Toxic or ill appearance
- Serious comorbid condition
- Findings
- Other testing to consider
- Enteric Pathogens Nucleic Acid Test Panels (PCR, NAAT)
- Older tests that have mostly been replaced in U.S. by more specific testing as above
- Fecal lactoferin
- Poor Test Specificity
- Fecal Leukocytes
- Stool Guaiac has the same Positive Predictive Value to identify Bacterial Diarrhea
- Bloody stool without Fecal Leukocytes suggests E coli 0157:H7 or Entamoeba histolytica
- Decreased Test Sensitivity with any delay in evaluation (samples easily degrade)
- Stool Culture
- Replaced by Enteric Pathogens Nucleic Acid Test Panels (PCR)
- Expensive and very low test senstitivity (5%)
- Indications
- Toxic appearance
- Prolonged Diarrhea >4 days
- Blood or pus in stool (or other signs of Inflammatory Diarrhea)
- Immunocompromised patients
- Ova and Parasites
- Low yield (requires multiple samples)
- Specific Stool ParasiteAntigens are preferred with better accuracy
- Indications
- Travel to developing countries
- Watery Diarrhea >7 days
- Fecal lactoferin
XII. Evaluation: Labs for specific presentations
- See Labs and Endoscopy below
-
Inflammatory Diarrhea or Dysentery
- Enteric Pathogens Nucleic Acid Test Panels (PCR) or Stool Cultures (SSCE)
- Salmonella including Salmonella typhi
- Shigella
- Campylobacter
- Escherichia coli 0157:H7 (STEC: Shiga Toxin E coli)
- Shiga Toxin (if bloody stool)
- Avoid Antimicrobial Agents
- Clostridium difficile Toxins
- Indicated for recent Antibiotics or Chemotherapy
- Consider Antibiotic coverage (if not STEC)
- Quinolone if suspected Shigellosis
- Macrolide for suspected Campylobacter
- Enteric Pathogens Nucleic Acid Test Panels (PCR) or Stool Cultures (SSCE)
- Nosocomial Diarrhea (after 3 days of hospitalization)
- Clostridium difficile Toxins
- Enteric Pathogens Nucleic Acid Test Panels (PCR) or SSCE culture
- Especially if nosocomial outbreak, age over 65 years, comorbidity or Immunocompromised
- Discontinue Antibiotics if possible
- Consider Flagyl if worsens or persists
- Persistent Diarrhea >7 days (esp. Immunocompromised)
- Fecal Lactoferrin (preferred over Fecal Leukocytes)
- High Test Sensitivity for SSCE Bacteria (up to 93%) as well as increased in Inflammatory Bowel Disease
- Parasitic Infection evaluation (esp. if adominal bloating, Eructation, Nausea)
- Fecal Lactoferrin (preferred over Fecal Leukocytes)
-
Immunocompromised
- See Diarrhea in HIV
- Consider Clostridium difficile Toxin (especially if recent Antibiotics or hospitalization)
- Consider Nucleic Acid Amplification Tests or SSCE Stool Culture (especially if Inflammatory Diarrhea)
- Consider Parasitic Infections (e.g. Cryptosporidium, especially if present >7 days)
- Consider other opportunistic infections (especially in HIV positive patients)
- Microsporidia
- Mycobacterium Avium Intracellulare Complex
- Cytomegalovrius
XIII. Evaluation: Endoscopy
- Indications
- Unclear diagnosis with persistent symptoms
- Suspected Tuberculosis
- Diffuse colitis (e.g. Clostridium difficile)
- Noninfectious Diarrhea cause evaluation (e.g. Inflammatory Bowel Disease)
- Does not distinguish Infectious from Inflammatory Diarrhea
- Immunocompromised condition (e.g. AIDS, HIV Infection)
-
Sexually Transmitted Disease (STD)
- Lesions in Distal 15 cm in homosexual men
- Herpes Virus
- NeisseriaGonorrhea
- Nonspecific findings limited to Rectum
- Biopsy and Culture show superficial exudates
- Syphilis
- Chlamydia (Lymphogranuloma venereum)
- Similar to Inflammatory Bowel Disease
XIV. Management: Vomiting
- See Vomiting
- See Antiemetic
- See Vomiting Management in Children
- See Vomiting in Pregnancy
XV. Management: General
- See Diarrhea Management in Children
- See Traveler's Diarrhea Management
- Intravenous Fluid indications
-
Electrolyte solutions containing Glucose (not Artificial Sweetener)
- Glucose assists with water reabsorption
- Oral Rehydration Solution (ORS) is preferred but may not be tolerated well
- See Oral Rehydration Solution
- Pedialyte, Rehydrate or Infalyte in children
- Gatorade or similar
- May be used as alternative (but not ideally formulated to match Diarrheal losses)
- Requires 1:1 dilution with water to half strength
- Dietary guidance
- Early reintroduction of food is recommended
- Decreases Diarrhea severity and duration
- Restores nutritional status earlier
- Duggan (1997) J Pediatr 131(6): 801-8 [PubMed]
- BRAT diet
- Includes Bananas, rice, apple sauce, toast, soup, crackers
- Reasonable and non-harmful, but not evidence-based
- Likely too restrictive, and patients are now encouraged to eat what they will tolerate
- Avoid provocative agents that worsen Diarrhea
- Early reintroduction of food is recommended
- Adjunctive measures
- Probiotics
- Show benefit in Pediatric Diarrhea, but not verified in adults
- Consider Lactobacillus GG (Culturelle) or Saccharomyces boulardii (Florastor)
- Decreases Diarrhea duration by one day, and decreases risk of prolonged Diarrhea
- Collinson (2020) Cochrane Database Syst Rev (12):CD003048 [PubMed]
- Zinc
- Reduces severity of Pediatric Diarrhea in developing countries, but not evaluated in adults in U.S.
- Probiotics
- Antidiarrheal medications
- Loperamide (Imodium)
- Antimotility properties
- Do not use Loperamide if fever or bloody stool are present (Inflammatory Diarrhea)
- Bismuth Subsalicylate (Pepto-Bismol)
- May be used in Inflammatory Diarrhea
- Antisecretory properties
- Contraindicated in children (contains Salicylates)
- Loperamide (Imodium)
XVI. Management: Antibiotics
- Use is controversial with potentially serious complications (e.g. Hemolytic Uremic Syndrome)
- Advantages
- Antibiotics appear to shorten Diarrhea course by 24 hours
- Effect is regardless of stool guiaic, fecal Leukocyte or Stool Culture result
- Disadvantages
- Most Acute Diarrheal is non-infectious, viral or self-limited
- Increased Antibiotic Resistance
- Increased risk of prolonged carrier state with certain infections (e.g. Salmonella)
- Increased risk of developing Hemolytic Uremic Syndrome with E. coli 0157:H7
- Increased risk of Clostridium difficile
- Contraindications
- Grossly bloody Diarrhea or other signs of Escherichia coli 0157:H7 (STEC: Shiga Toxin E coli)
- Risk of Hemolytic Uremic Syndrome increases with Antibiotic use
- Grossly bloody Diarrhea or other signs of Escherichia coli 0157:H7 (STEC: Shiga Toxin E coli)
- Indications
- Findings suggestive of Bacterial Diarrhea
- Guiaic positive stool (not grossly bloody stool)
- Fecal Leukocyte positive
- Overseas travel
- Diarrheal illness lasting longer than 10-14 days
- Immunocompromised patients
- Severe illness or Sepsis
- Age over 65 years old
- Findings suggestive of Bacterial Diarrhea
- Empiric Antibiotics
- See Traveler's Diarrhea Management
- Ciprofloxacin (adults)
- Empiric adult dose: 500 to 1000 mg once or 500 mg twice daily for 3 days
- Preferred agent for E. coli (ETEC, EIEC), Shigella
- Also covers Campylobacter, Salmonella, Yersinia, Cryptosporidium
- Trimethoprim-Sulfamethoxazole (Septra, Bactrim)
- Empiric adult dose: One DS twice daily for 3-5 days
- Preferred agent for Cyclospora or Isospora
- Also covers E. coli (ETEC, EIEC), Salmonella, Shigella, Vibrio Cholerae, Yersinia (Septra has higher resistance rates)
- Used in combination with Aminoglycoside to treat non-Vibrio Cholerae
- Azithromycin
- Empiric adult dose: 500 mg daily for 3 days
- Preferred agent for Campylobacter
- Also covers E. coli (ETEC), Salmonella, Shigella, Vibrio Cholerae
- Third Generation Cephalosporin (e.g. Cefdinir, Cefpodoxime)
- Consider in children for Shigella, Salmonella
- Ceftriaxone is a first line agent in Non-Typhoidal Salmonella and Shigella
- Covers Yersinia enterocolitica and Salmonella enterica, typhi or paratyphi (Ceftriaxone)
- Other Antibiotics used for specific indications
- Metronidazole
- Preferred agent for Entamoeba histolytica
- Alternative agent for Clostridium difficile (but high failure rate), and Giardia
- Azithromycin
- Campylobacter (treat with 3-5 day course)
- Shigella
- Ciprofloxacin
- Non-Typhoidal Salmonella (other Fluoroquinolones are also effective)
- Salmonella enterica, typhi or paratyphi
- Shigella (Reduces duration and shedding)
- Campylobacter (alternative agent)
- Yersinia enterocolitica
- Doxycycline
- Preferred agent for Vibrio Cholerae
- Used in combination with Ceftriaxone to treat non-Vibrio Cholerae
- Also covers Yersinia (when combined with an Aminoglycoside)
- Oral Vancomycin
- Alternative agent for Clostridium difficile
- Fidaxomicin (Dificid)
- Preferred agent for Clostridium difficile
- Amoxicillin
- Non-Typhoidal Salmonella
- Metronidazole
-
Antiparasitic Agents used for specific indications
- See Metronidazole indications above
- Albendazole (Albenza)
- Preferred agent for Microsporida
- Tindazole (Tindazole)
- Covers Entamoeba histolytica (when treated in combination with Paromomycin)
- Preferred agent for Giardia
- Nitazoxanide (Alinia)
- Covers Cryptosporidium
- Preferred agent for Giardia
XVII. Management: Admission Criteria
- Severe Diarrhea with difficulty maintaining hydration
- Very young or very old
- Severe comorbid illness
- Severe pain
- High fever
- Intractable Vomiting
XVIII. Prevention
- See Water Disinfection
- See Traveler's Diarrhea Prevention
- See Foodborne Illness Prevention
-
Hand Washing
- Wash with soap and water for at least 20 seconds ("Mary had a little lamb...") before rinsing
- Decreases Infectious Diarrhea Incidence by one third
- Ejemot (2008) Cochrane Database Syst Rev (1):CD004265 [PubMed]
- Healthcare workers and food workers should not return to work until symptoms have resolved for 48 hours
-
Vaccinations
- Rotavirus (part of Primary Series in U.S. for infants)
- Typhoid Vaccine (frequently required for overseas Travel Immunizations)
- Cholera Vaccine
- CDC Reportable Illnesses (National Notifiable Diseases Surveillance System or NNDSS)
- https://wwwn.cdc.gov/nndss/data-and-statistics.html
- Listeria monocytogenes
- Typhoid Fever (Salmonella typhi)
- Trichinellosis
- Cyclospora
- Vibrio
- Shiga-toxin producing E. coli (e.g. E. coli 0157:H7, Enterohemorrhagic E. coli)
- Giardiasis
- Foodborne Botulism
- Shigella
- Post-Diarrhea; Hemolytic Uremic Syndrome
XIX. Complications: Postinfectious Diarrhea Conditions
- Erythema Nodosum
- Glomerulonephritis
- Guillain-Barre Syndrome
- Hemolytic Anemia
- Hemolytic Uremic Syndrome
- IgA Nephropathy
- Lactose Intolerance (transient)
- Meningitis
- Reactive Arthritis
- Postinfectious Irritable Bowel Syndrome
- Bowel Perforation
XX. Resources
- IDSA Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea (2017)
XXI. References
- Glauser and Schafer (2020) Crit Dec Emerg Med 34(1):3-12
- May and Mason in Herbert (2021) EM:Rap 21(6): 15-6
- Herbert (2012) EM:RAP-C3 2(4): 2
- Barr (2014) Am Fam Physician 89(3): 180-9 [PubMed]
- Guerrant (2001) Clin Infect Dis 32:331-48 [PubMed]
- Meisenheimer (2022) Am Fam Physician 106(1): 72-80 [PubMed]
- Scallen (2011) Emerg Infect Dis 17(1): 7-15 [PubMed]
- Shane (2017) Clin Infect Dis 65(12): e45-80 [PubMed]