The document discusses the clinical features, pathology, microbiology, and emergency department (ED) management of acute diarrheal diseases. It covers the major causes of diarrhea including viruses, bacteria, and protozoa. In the ED, management involves assessing hydration status, providing rehydration with oral or IV fluids, and considering antibiotics for likely bacterial infections. The role of the ED physician is to exclude serious illness, ensure stability, begin diagnostic evaluation if needed, and provide referral for further care.

1. The clinical features,
pathology, microbiology
and ER management of
acute diarrheal diseases,
including HIV-related
gastrointestinal infections
Dr. Peter Andre Soltau

2. Background / Incidence
• The W.H.O reports > 3 million episodes of diarrhea annually and
estimates > 2.2 million diarrheal deaths occur mainly in children,
especially in low- and middle-income countries
• Diarrheal diseases represent one of the five leading causes of death
worldwide
• Commonly called the "nuisance disease"

3. Definitions
• Acute primary diarrhea defined as 3 or more loose/
watery/ diarrheal stools in a 24-hour period
• Duration:
• Acute < 14 days
• Persistent > 14 days
• Chronic > 30 days
• Dysentery - frequent passage of small volume stools
assoc. blood, mucus, abdominal cramping and tenesmus

4. Severe Diarrhea - 4 or more stools per day for 3 or
more days associated with [abdominal
symptoms(cramps, nausea, vomiting, tenesmus) or
systemic symptom (fever, malaise, dehydration)].

5. Classifying Diarrhea
• Secretory vs Osmotic
• Infectious vs Non-Infectious
• Inflammatory vs Non Inflammatory

6. Secretory diarrhea
• Due to abnormal electrolyte transport across the intestinal
epithelial cells
• Increased secretion and/or decreased absorption result
• The diarrhea is not related to the intestinal contents and
therefore typically does not stop with fasting.
• Infection (e.g., cholera) is the most common cause of
secretory diarrhea
• The fluid losses can be enormous.

8. Osmotic diarrhea
• The presence of nonabsorbable solute exerts an osmotic
pressure effect across the intestinal mucosa, resulting in
excessive water output
• Stops during fasting
• The offending molecule is usually a carbohydrate or divalent
ion.
• Common examples include mannitol or sorbitol, epson salt
(MgSO4) and some antacids (MgOH2).

9. Malabsorption
• Inability to absorb certain carbohydrates is the most common
deficit, but it can result virtually from any type of
malabsorption.
• E.g. lactose intolerance: a deficiency in the brush border
enzyme lactase.

10. Etiology
• Infectious:
• Viruses
• Norovirus, rotavirus, adenoviruses, astrovirus, and others
• Bacteria
• Salmonella, campylobacter, shigella, enterotoxigenic E. coli, C. difficile,
vibrio species and others
• Protozoa
• Cryptosporidium, giardia l., cyclospora, entamoeba h., and others

11. Etiology
• Dietary Disturbances:
• Overfeeding, food allergy, starvation stools
• Anatomic Abnormalities
• Intussusception, hirschsprung, partial obstruction, appendicitis,
blind loop syndrome, short bowel syndrome
• Inflammatory Bowel disease
• Malabsorption or secretory diseases
• Cystic fibrosis, celiac disease, disaccharidase deficiency
• Systemic Diseases
• Immunodificiency, endocrinopathy (CAH, thyroid disorders)
• Miscellaneous
• Antibiotic associated, secondary lactase deficiency, irritable colon
syndrome, toxins, HUS

12. Pathology - Infectious
• Pathogenic organisms must be swallowed, they must
survive the acid in the stomach, intestinal immunity,
motility, mucus, and the resident micro flora, then
colonize the small bowel and stick to the enterocytes.
They then produce their harmful effects by one of
several mechanisms

14. Viral Pathogens
• Invade & destroy the small intestinal mucosa villous epithelium
• Loss of mature absorptive cells
• Regeneration of poorly differentiated intestinal epithelial cells
• Impaired salt and water absorption
• Carbohydrate malabsorption leading to osmotic diarrhea

15. Bacterial Pathogens
• Invasive:
• Adhere to mucosal cells followed by invasion and multiplication,
initiating an acute mucosal inflammatory reaction, leading to
ulceration and synthesis of a variety of secretagogues. esp. in large
intestine
• E.g. Shigella, Salmonella, Yersinia enterocolitica, campylobacter
jejuni, vibrio parahemolyticus
• Cytotoxic:
• Elaboration of cytotoxins which can either inhibit protein synthesis
or induce secretion of inflammatory mediators causing cell death
and hence decrease the intestinal absorptive surface area
• E.g. Shigella, E.coli, clostridium difficile

16. Bacterial Pathogens
• Toxigenic
• Colonize the small intestines and secrete enterotoxins which bind
mucosal receptors and increase an intracellular mediator altering
salt and water transport (mucosal integrity is unchanged)
• E.g. Shigella, E.coli, Yersinia E., Vibrio cholerae
• Adherent:
• Colonize and adhere to intestinal surface of small and large
intestine, indenting the surface and flattening the microvilli,
thereby decreasing the surface area
• E.g. E. coli

17. Microbiology
• Laboratory testing:
• Routine testing for specific pathogens is not recommended
• Reserve laboratory testing and stool cultures for select
circumstances.
• Criteria vary but often include bloody diarrhea, weight loss,
diarrhea leading to dehydration, fever, neurologic
involvement, sudden onset of severe abdominal pain,
persistent (> 7 days) diarrhea, or possible community-acquired
diarrhea, traveler’s diarrhea, or nosocomial diarrhea

18. ED management

19. ED Management
History Of Present Illness
• Type and volume of stools:
• Associated symptoms: nausea, vomiting, abdominal pain, fever, and tenesmus
•
•
•
•
•
Character and location of any abdominal pain
Duration of symptoms
Weight loss
Indicators of dehydration
Epidemiological risk factors
• Recent diet, ingestion of seafood, raw or undercooked meat, eggs, or milk
products
• Recent foreign travel
• Lake or stream swimming
• Visits to a farm
• Ill contacts,
• Group living arrangements (e.g., nursing home, college dormitory) or day
care attendance

20. • Past Medical History
• Comorbidities
• Immunosuppression
• Crohn’s disease or ulcerative colitis
• Medications
• prescription, over-the-counter, and herbal preparations
• laxatives, antibiotics, magnesium- or calcium-containing antacids.
• alpha-glucosidase inhibitors (e.g., acarbose, miglitol)
• Artificial sweeteners containing sorbitol or mannitol
• Enteral tube feedings

21. • Social History
• Occupational history (veterinarian, food handler, or
day care center or nursing home employee)
• Sexual preference
• Inquire about alcohol and drug use

22. Indications for diagnostic
evaluation
• Profuse watery diarrhea with signs of hypovolemia
• Passage of many small volume stools containing blood and
mucus
• Bloody diarrhea
• Temperature ≥38.5ºC (101.3ºF)
• Passage of ≥6 unformed stools per 24 hours or a duration of
illness >48 hours
• Severe abdominal pain
• Recent use of antibiotics or hospitalized patients
• Diarrhea in the elderly (≥70 years of age) or the
immunocompromised

23. Tests
• Blood Tests
• CBC: unnecessary in most
• Chem Path: unnecessary in most
• Fecal Leukocyte/Lactoferrin Testing:
• Community-acquired or traveler’s diarrhea, nosocomial
diarrhea, and diarrhea persisting more than seven days
have been suggested

24. • Stool Culture
• the yield on routinely obtained stool cultures is low (1 -5%)
• Indicated :
•
•
•
•
•
history of bloody stools (grossly bloody or heme-positive stools)
stools containing leukocytes or lactoferrin;
immunocompromised patients; fever higher than 38.5°C (101.3°F);
systemic illness or an illness that is clinically severe or persistent;
patients with severe abdominal pain.
• Stool testing for Parasites
• diarrhea lasting more than 14 days
• immunocompromised
• not responded to antimicrobial therapy

25. ED Management

26. HIV/ AIDS
• Prone to diarrheal Illnesses, in developing world up to 100%
• Increased risk due to:
• Develop enteric infections from a variety of unusual viral,
parasitic, protozoal, and bacterial organisms
• Malignancies (lymphoma/Kaposi's sarcoma)
• Multiple course of antibiotics – antibiotic associated diarrhea
• Stool culture should be done, along with C. difficile toxin and
ova and parasite
• If negative consider endscopic investigation

28. Treatment
• Rapidly assess hydration status, risk factors for likely bacterial
pathogen, and need for symptomatic relief
• Rehydration - IV VS ORT
• Diarrhea relief include loperamide, diphenoxylate, and
bismuth subsalicylate

29. Oral rehydration Therapy
• Directed at preventing or treating dehydration, replacing
ongoing fluid loss, and meeting nutritional needs
• Correct fluid deficit over 4 hours
• 50 – 100mls of ORS/ kg
• Aim for 30mls of ORS/kg per hour
• Pedialyte, Lytren, and Rehydrolyte

30. IV Fluids
• Indicated for severe dehydration, hemodynamic instability,
altered mental status
• 20 ml/kg bolus in children

31. Controversial Treatments
• Probiotics – microorganisms used to colonize the
intestine and treat or prevent diarrhea, found to reduce
duration on average 0.7 days, and frequency by 1.6 per
day
• Zinc – RCT suggests a reduction in duration and severity
of acute and persistent diarrhea, however more likely to
vomit
• Ramoplanin – a new antibiotic in Phase II development
for C. difficile associated diarrhea

32. Role of Antibiotics
• Empiric antibiotics should be considered for patients:
•
•
•
•
with acute dysentery
moderate-to-severe traveler’s diarrhea
Diarrhea lasting longer than two and a half days
fever greater than 38.5°C (101.3°F) plus either leukocyte-, lactoferrin, or hem occult-positive stools
• Fluoroquinolones for adults and trimethoprimsulfamethoxazole
(TMP-SMX) for children are reasonable

33. Disposition / Follow Up
• Decision relies heavily on physician judgment
• Most commonly – clinically stable, benign exam and low risk for
complications – safely discharged with follow up
• Moderate or severe dehydration, intractable or bilious vomiting,
surgical cause of vomiting, neurological abnormalities, large
ongoing losses, poor social support are candidates for admission
• Special consideration for patients with diagnostic dilemma,
extremes of age, immunocompromised, or multiple or severe
comorbidities
• Discharge instructions are mandatory both verbal and written

34. Transmission Prevention
• Good hand washing hygiene
• Travel Precautions
• Immunization - Rotavirus vaccines
• Patient & family education

35. Summary
• The role of the emergency physician is to exclude serious
illness, ensure patient stability, begin an investigation to
exclude infectious causes of diarrhea, and provide timely
referral for further evaluation
• This diagnostic evaluation usually exceeds the scope of most
ED capabilities
• If there is a doubt about the diagnosis, ED observation and
repeated examinations can be helpful.
• Patients warranting a greater level of concern are the very
young, the elderly, immunocompromised individuals, those
with major comorbidities, and those with unusual or atypical
presentations