The clinical features,
pathology, microbiology
and ER management of
acute diarrheal diseases,
including HIV-related
gastro...
Background / Incidence
• The W.H.O reports > 3 million episodes of diarrhea annually and
estimates > 2.2 million diarrheal...
Definitions
• Acute primary diarrhea defined as 3 or more loose/
watery/ diarrheal stools in a 24-hour period
• Duration:
...
Severe Diarrhea - 4 or more stools per day for 3 or
more days associated with [abdominal
symptoms(cramps, nausea, vomiting...
Classifying Diarrhea
• Secretory vs Osmotic
• Infectious vs Non-Infectious
• Inflammatory vs Non Inflammatory
Secretory diarrhea
• Due to abnormal electrolyte transport across the intestinal
epithelial cells
• Increased secretion an...
Osmotic diarrhea
• The presence of nonabsorbable solute exerts an osmotic
pressure effect across the intestinal mucosa, re...
Malabsorption
• Inability to absorb certain carbohydrates is the most common
deficit, but it can result virtually from any...
Etiology
• Infectious:
• Viruses
• Norovirus, rotavirus, adenoviruses, astrovirus, and others

• Bacteria
• Salmonella, ca...
Etiology
• Dietary Disturbances:
• Overfeeding, food allergy, starvation stools

• Anatomic Abnormalities
• Intussusceptio...
Pathology - Infectious
• Pathogenic organisms must be swallowed, they must
survive the acid in the stomach, intestinal imm...
Viral Pathogens
• Invade & destroy the small intestinal mucosa villous epithelium
• Loss of mature absorptive cells
• Rege...
Bacterial Pathogens
• Invasive:
• Adhere to mucosal cells followed by invasion and multiplication,
initiating an acute muc...
Bacterial Pathogens
• Toxigenic
• Colonize the small intestines and secrete enterotoxins which bind
mucosal receptors and ...
Microbiology
• Laboratory testing:
• Routine testing for specific pathogens is not recommended
• Reserve laboratory testin...
ED management
ED Management
History Of Present Illness
• Type and volume of stools:
• Associated symptoms: nausea, vomiting, abdominal p...
• Past Medical History
• Comorbidities
• Immunosuppression
• Crohn’s disease or ulcerative colitis

• Medications
• prescr...
• Social History
• Occupational history (veterinarian, food handler, or
day care center or nursing home employee)
• Sexual...
Indications for diagnostic
evaluation
• Profuse watery diarrhea with signs of hypovolemia
• Passage of many small volume s...
Tests
• Blood Tests
• CBC: unnecessary in most
• Chem Path: unnecessary in most
• Fecal Leukocyte/Lactoferrin Testing:

• ...
• Stool Culture
• the yield on routinely obtained stool cultures is low (1 -5%)
• Indicated :
•
•
•
•
•

history of bloody...
ED Management
HIV/ AIDS
• Prone to diarrheal Illnesses, in developing world up to 100%
• Increased risk due to:
• Develop enteric infect...
Treatment
• Rapidly assess hydration status, risk factors for likely bacterial
pathogen, and need for symptomatic relief
•...
Oral rehydration Therapy
• Directed at preventing or treating dehydration, replacing
ongoing fluid loss, and meeting nutri...
IV Fluids
• Indicated for severe dehydration, hemodynamic instability,
altered mental status
• 20 ml/kg bolus in children
Controversial Treatments
• Probiotics – microorganisms used to colonize the
intestine and treat or prevent diarrhea, found...
Role of Antibiotics
• Empiric antibiotics should be considered for patients:
•
•
•
•

with acute dysentery
moderate-to-sev...
Disposition / Follow Up
• Decision relies heavily on physician judgment
• Most commonly – clinically stable, benign exam a...
Transmission Prevention
• Good hand washing hygiene

• Travel Precautions
• Immunization - Rotavirus vaccines

• Patient &...
Summary
• The role of the emergency physician is to exclude serious
illness, ensure patient stability, begin an investigat...
Diarrhoea by Dr Peter Soltau 2014
Diarrhoea by Dr Peter Soltau 2014
Diarrhoea by Dr Peter Soltau 2014
Diarrhoea by Dr Peter Soltau 2014
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Diarrhoea by Dr Peter Soltau 2014

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Diarrhoea

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  • Tenesmus -ineffectual and painful straining at stool, feeling of incomplete emptying
  • Bacterial causes are responsible for most cases of severe diarrhea. This was illustrated in a study of 173 healthy adults with severe (defined as ≥4 fluid stools per day for more than three days) acute community-acquired diarrhea; a bacterial pathogen was identified in 87 percent of cases
  •  Secretory diarrhea is caused by these chain of events.Two types of bacteria produce diarrhea in a similar way, Vibrio cholerae and enterotoxigenic Escherichia coli(ETEC). After adhering (sticking) to the wall of the bowel, a toxin enters the enterocytes and stimulates an enzyme called adenylatecyclase (see Figure 2). This causes a chain of reactions which releases energy and results in the secretion of sodium and chloride ions (electrolytes) - accompanied by water - into the lumen of the bowel.Once a cell has been stimulated in this way it will continue to secrete fluid and electrolyte for the rest of its short life. With thousands and even millions of enterocytes all secreting uncontrollably, the bowel cannot reabsorb all the fluid and the result is watery diarrhea. This 'secretory diarrhea' can cause dehydration, circulatory collapse and death.
  • In such cases, a moderate quantity of lactose is consumed (usually as milk), but the intestinal epithelium is deficient in lactase, and lactose cannot be effectively hydrolyzed into glucose and galactose for absorption. The osmotically-active lactose is retained in the intestinal lumen, where it "holds" water. To add insult to injury, the unabsorbed lactose passes into the large intestine where it is fermented by colonic bacteria, resulting in production of excessive gas.
  • •VIRUS  DIARRHOEA (e.g. Rotavirus)Effect on villus structure and functionEnzyme damageSignificant effect on digestion and absorptionSecretion-absorption imbalance
  • Invasive diarrheaOther pathogens produce diarrhea in a different way. The Shigella bacteria not only colonise the surface of the small bowel but they also penetrate and invade the mucous membrane. Many enterocytes are destroyed, blood vessels may rupture, the white cells of the patient's defense mechanism die and are excreted as pus along with blood and tissue fluid. The result is dysentery diarrhea. Other invasive germs include the food-poisoning Salmonellae bacteria. These cause less local damage but penetrate blood vessels causing bacteremia - circulation of pathogens in the bloodstream - and generalized illness with fever and vomiting.The rotavirus is also a common cause of acute diarrhea in small children. The organisms penetrate the small bowel in patches, killing many enterocytes and in this way reducing the surface for absorption. They may also have some secretory mechanism since they often produce a watery diarrhea.
  • When vomitingis a prominent feature of the patient’s symptoms,viruses are the more likely etiologic agents.12,37 Fevergreater than 38.5°C (101.3°F) is usually associated withintestinal inflammation due to invasive bacteria (e.g.: Pain iscommon in patients with mesenteric ischemia, inflammatorybowel disease, and irritable bowel syndrome.22Symptom duration can helpnarrow the differential diagnosis. Viral gastroenteritisusually lasts 12-60 hours.2 Thus, it is less likely thatdiarrhea lasting more than a couple of days or so isviral. Diarrhea lasting greater than two weeks often hasa different etiology (see Table 3) than diarrhea that hasbeen present for less than two weeks.37Determine whether the patient has lostweight. Patients with diarrhea may have weight lossbecause of both increased output and reduced intake.Substantial weight loss is more likely due to ischemia,neoplasm, or malabsorptive syndromes.22 Weight lossmay be an indicator of dehydration in children.Asking about urine output,dizziness, thirst, and syncope—as well as askingfamily members or prehospital personnel about alteredmental status—is useful in assessing the patient’svolume status.
  • A chemistry panel may reveal an electrolyteimbalance or the degree of dehydration in systemically illpatients, or in those with severe or persistent diarrhea. Inpatients with bloody diarrhea, obtain a CBC and plateletcount to exclude hemolytic uremic syndrome. (Hemolyticuremic syndrome is discussed in further detail in the sectionon pediatric patients later in this article.) Eosinophilia on theleukocyte differential can point to food allergy, collagenvasculardiseases, neoplasm, parasitic infections, or eosinophilicgastroenteritis or colitis.22 Such diagnostic testingshould be reserved for select cases in which clinical orepidemiologic factors or disease severity suggest theirneed.5 Unfortunately, the literature does not provide clearcutindications for such testing.
  • Immunocompromized PatientsPatients with HIV/AIDS are especially prone to diarrhealillnesses. About half of North American AIDS patients willdevelop diarrhea at some point in their illness. The incidenceof diarrhea in AIDS patients throughout the develop-ing world approaches 100%.65While HIV/AIDS patients are at risk for all of thediarrheal ailments that afflict the immunocompetentpopulation, they can develop enteric infections from avariety of unusual viral, parasitic, protozoal, and bacterialorganisms. Malignancies affecting the gastrointestinal tract,such as lymphoma and Kaposi’s sarcoma, may producediarrhea, as can many antiretroviral medications.65,66 Finally,many AIDS patients receive multiple or sustained courses ofantibiotics, predisposing them to C. difficile-associateddiarrhea.66 Therefore, it is important to maintain a broaddifferential diagnosis, consider a more aggressive diagnosticstrategy, involve consultants early when appropriate, andconsider hospitalization to improve diagnostic certaintythrough a combination of testing, observation, and consultantinvolvement. (See also the January 2002 issue ofEmergency Medicine Practice, “HIV-Related Illnesses: TheChallenge Of ED Management.”)Because certain symptoms may suggest particularorganisms (see Table 5), the approach to the HIV/AIDSpatient with diarrhea begins with the history. Definitivediagnosis, however, is likely to result from either microbiologicalstudies or endoscopy.65,66 Begin by assessing thepatient’s immune status. Ask about specific exposures(sexual practices, travel history, and medications includingrecent antibiotics). Inquire also about the stool characteristics(bloody, mucoid, watery) and all associated symptoms(e.g., fever, vomiting, abdominal pain or cramping, tenesmus,bloating, weight loss).65,66 What may seem like an acutebout of diarrhea may actually represent the beginning ofchronic symptoms. Routine laboratory tests should beordered based on the clinical situation.65 Many authoritiesrecommend that in AIDS patients, a stool culture should bedone, along with C. difficile toxin and ova and parasitetesting.66 If these studies are negative, referral to a gastroenterologistfor endoscopic investigations could be the nextstep in the patient’s evaluation.65,66 In the AIDS patient withchronic diarrhea and a negative microbiological work-up forinfectious agents, authorities are divided on the bestapproach. Some advocate symptomatic care, some a courseof empiric antibiotics, and still others suggest endoscopy disease stage guide these decisions.17 Endoscopy oftenproduces a definitive diagnosis in AIDS patients withchronic diarrhea and negative stool studies.67ED treatment options include rehydration, antimotilityagents, and empiric antibiotics, as discussed earlier in thisarticle. Consultation or referral to the patient’s primary careprovider or infectious disease specialist regarding antibiotictherapy or changes in antiretroviral therapy are advisable.
  • afebrile and have non-bloodydiarrhea as well as most patients with chronic diarrheaassociated with inflammatory bowel disease may benefitfrom the use of antimotility agents.28 Antimotility agentsshould generally be avoided in patients with high fever,sepsis, immunocompromise, bloody diarrhea, or suspectedinflammatory diarrhea because of delayed clearance ofenteric pathogens, prolonged fever, and toxic megacolon
  • Controversies/Cutting EdgeProbioticsProbiotics are microorganisms that some have used in a variety of settings and clinical circumstances to colonize the intestine to prevent or treat diarrhea. One recent meta-analysis of probiotic use in children hospitalized with acute gastroenteritis found that probiotics are a useful adjuvant along with rehydration therapy in acute gastroenteritis.73 Another meta-analysis of oral Lactobacillus (the most-studied probiotic) treatment of children with acute infectious diarrhea found that diarrhea duration was reduced an average of 0.7 days, and stool frequency decreased by an average of 1.6 per day.74 A third recent meta-analysis of probiotics for antibiotic-associated diarrhea found that diarrhea occurred in 23% of patients not receiving a probiotic agent and in 13% of patients receiving a probiotic.75 This meta-analysis involved children and adults.While probiotics are not standard therapy for adults or children with diarrhea in the United States, they are available over-the-counter in a variety of retail outlets, and patients may ask about their utility in diarrheal illnesses.ZincIn 2000, a pooled analysis of randomized, controlled trials of zinc therapy in children under 5 years of age with diarrhea concluded that zinc supplementation reduces the duration and severity of acute and persistent diarrhea.76 A more recent randomized, controlled clinical trial studied the effects of zinc administration in children with diarrhea. This study was done in Nepalese children 6-35 months of age with acute diarrhea. Findings were that zinc supplementation substantially reduced diarrhea duration and that those in the zinc group were more likely to vomit than those in the placebo group.77 It should be noted that the studies referenced above were conducted primarily in the developing world, where zinc deficiency in children is prevalent. In the United States, zinc administration to children with diarrheal illnesses is not a part of standard therapy. Ramoplanin For C. difficile-Associated Diarrhea A new antibiotic, ramoplanin, is currently in Phase II development for C. difficile-associated diarrhea. This antibiotic also has activity against vancomycinresistant Enterococcus species and other enteric organisms.78 Ramoplanin is an oral agent and is not systemically absorbed.79 
  • Diarrhoea by Dr Peter Soltau 2014

    1. 1. The clinical features, pathology, microbiology and ER management of acute diarrheal diseases, including HIV-related gastrointestinal infections Dr. Peter Andre Soltau
    2. 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. 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. 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. 5. Classifying Diarrhea • Secretory vs Osmotic • Infectious vs Non-Infectious • Inflammatory vs Non Inflammatory
    6. 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.
    7. 7. 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).
    8. 8. 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.
    9. 9. 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
    10. 10. 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
    11. 11. 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
    12. 12. 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
    13. 13. 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
    14. 14. 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
    15. 15. 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
    16. 16. ED management
    17. 17. 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
    18. 18. • 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
    19. 19. • Social History • Occupational history (veterinarian, food handler, or day care center or nursing home employee) • Sexual preference • Inquire about alcohol and drug use
    20. 20. 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
    21. 21. 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
    22. 22. • 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
    23. 23. ED Management
    24. 24. 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
    25. 25. 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
    26. 26. 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
    27. 27. IV Fluids • Indicated for severe dehydration, hemodynamic instability, altered mental status • 20 ml/kg bolus in children
    28. 28. 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
    29. 29. 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
    30. 30. 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
    31. 31. Transmission Prevention • Good hand washing hygiene • Travel Precautions • Immunization - Rotavirus vaccines • Patient & family education
    32. 32. 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
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