Diarrhea Flashcards by Ximenaherrera Barrones

What is the definition of diarrhea?

Decreased stool consistency and/or increased frequency, with stool output >200 g/day.

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What is the age distribution pattern of acute diarrhea based on the provided chart?

Peaks at ages 11-20 and 61-70 (both ~140 cases), with lower incidence in other age groups (e.g., ~50 cases at ages 0-10, 21-30, and 81-90).

Chart shows a U-shaped distribution with higher incidence in adolescents/young adults and elderly.

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What are the exogenous sources of intestinal fluid contributing to diarrhea?

Food and beverages (~2 liters daily).

Endogenous sources (7 liters) include saliva, gastric acid, intestinal secretion, pancreatic, and biliary secretions.

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What is the role of the intestinal villus and microvilli in diarrhea?

Intestinal villi and microvilli (microvellosidades) increase surface area for absorption. Damage or dysfunction (e.g., by pathogens) impairs absorption, leading to diarrhea.

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How does glucose and sodium transport occur in the intestinal lumen?

Glucose and Na⁺ are co-transported from the intestinal lumen into epithelial cells, facilitating water absorption. Disruption (e.g., by toxins) causes diarrhea.

Diagram shows Na⁺ and glucose movement across epithelial cells.

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How is diarrhea classified based on duration?

Acute: <14 days

Persistent: 14-30 days

Chronic: >30 days

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What are the main classification categories for diarrhea?

Duration

Clinical syndromes

Etiology

Physiopathology

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What are the main infectious causes of diarrhea?

Viral

Bacterial

Parasitic

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Name the bacterial causes of diarrhea listed in the document.

Escherichia coli

Campylobacter jejuni

Vibrio cholerae

Shigella spp.

Salmonella (non-typhi and typhi)

Clostridium difficile

Yersinia enterocolitica

Staphylococcus aureus

Bacillus cereus

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Name the parasitic causes of diarrhea listed in the document.

Giardia lamblia

Enterobius vermicularis

Isospora belli

Trichomonas hominis

Ascaris lumbricoides

Entamoeba histolytica

Cryptosporidium parvum

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Name the viral causes of diarrhea listed in the document.

Rotavirus

Adenovirus

Astrovirus

Norovirus

Hepatitis A

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What are the characteristics and clinical presentation of ETEC (Enterotoxigenic E. coli)?

Characteristics: Releases two toxins, one similar to cholera toxin.

Clinical Presentation: Nausea, vomiting, abdominal pain, massive liquid diarrhea.

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What are the characteristics and clinical presentation of EIEC (Enteroinvasive E. coli)?

Characteristics: Invades intestinal epithelium, causing cell destruction.

Clinical Presentation: Fever, abdominal pain, blood and pus in feces.

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What are the characteristics and clinical presentation of EPEC (Enteropathogenic E. coli)?

Characteristics: Causes loss of microvilli.

Clinical Presentation: Fever, vomiting, liquid diarrhea with mucus.

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What are the characteristics and clinical presentation of EHEC (Enterohemorrhagic E. coli)?

Characteristics: Releases a toxin similar to Shiga toxin.

Clinical Presentation: Fever, abdominal pain, bloody diarrhea.

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What are the key differences between disenteriform and choliform diarrhea syndromes?

Disenteriform: Frequent fever, intense hypogastric pain, rectal tenesmus, large bowel, mucosal invasion.

Choliform: No fever, frequent vomiting, mild mesogastric pain, small bowel, toxin-mediated.

Disenteriform involves pathogens like Shigella; choliform involves Vibrio cholerae.

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Which microorganisms are associated with disenteriform diarrhea?

Shigella

EIEC

Salmonella enteritidis

Campylobacter jejuni

Clostridium difficile

Entamoeba histolytica

Balantidium coli

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Which microorganisms are associated with choliform diarrhea?

Vibrio cholerae

ETEC, EPEC

Clostridium perfringens

Rotavirus

Giardia lamblia

Cryptosporidium

Staphylococcus aureus

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What are the four physiopathological types of diarrhea?

Osmotic

Secretory

Exudative (Inflammatory)

Motor

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Describe the mechanism of osmotic diarrhea.

Pathogens adhere to enterocyte brush border, blocking water and electrolyte absorption.

Excess carbohydrates in the intestinal lumen cause acidic diarrhea.

Figure 3 shows lactase deficiency leading to unabsorbed lactose causing symptoms.

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What are the causes of osmotic diarrhea?

Exogenous: Laxatives, food (sorbitol, mannitol, xylitol), viruses (rotavirus, adenovirus), parasites (Giardia, Cryptosporidium), bacteria (EAEC, EPEC).

Endogenous: Disaccharidase deficiency (lactase, sucrase), malabsorption syndromes (celiac disease), pancreatic exocrine insufficiency.

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What are the clinical features of osmotic diarrhea?

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Abdominal distention

Pain

Flatulence

Liquid diarrhea

Stops with fasting (48-72 hours)

What are the causes of secretory diarrhea?

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Exogenous: Laxatives, medications (quinidine, theophylline, prostaglandins), bacteria (V. cholerae, ETEC, Shigella, EPEC), toxins (arsenic, alcohol, shellfish, coffee, fungi), S. aureus toxins.

Endogenous: Bile salt malabsorption, hormone-secreting tumors, neuropathy.

What are the clinical features of secretory diarrhea?

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Abundant liquid diarrhea

No fever

Mild abdominal pain

Dehydration

May stop with fasting

Describe the mechanism of inflammatory (exudative) diarrhea.

Enterocyte damage by infectious agents triggers an inflammatory response. This causes exudation of protein, blood, mucus, or pus into the lumen.

What are the causes of inflammatory (exudative) diarrhea?

Infectious (Invasive): Shigella, EIEC, Salmonella (non-typhi), Campylobacter jejuni, Yersinia enterocolitica, Entamoeba histolytica. Non-infectious: Inflammatory bowel disease, ischemic colitis, radiation, autoimmune conditions, cancer.

What are the clinical features of inflammatory (exudative) diarrhea?

Dysentery (bloody stools) Fever Abdominal pain (hypogastrium) Rectal tenesmus

Describe the mechanism of motor diarrhea.

Increased or decreased intestinal motility reduces epithelial contact time, leading to excessive water in the large bowel and absorption saturation, causing diarrhea.

What are the causes of motor diarrhea?

Increased Motility: Irritable bowel syndrome (IBS), diabetic neuropathy, hypothyroidism, gastrectomy. Decreased Motility: Diabetes, scleroderma, anticholinergic drugs.

How is diarrhea classified based on stool characteristics and severity?

Watery: Mild Moderate to severe Bloody: Temperature ≤37.7°C Temperature ≥38.3°C

Which pathogens are associated with non-bloody diarrhea?

Staphylococcus aureus ETEC Salmonella Bacillus cereus Vibrio cholerae

Which pathogens are associated with bloody diarrhea?

EIEC, EHEC Shigella Entamoeba histolytica Campylobacter jejuni Salmonella Yersinia enterocolitica

What are the incubation period and source for Staphylococcus aureus in non-bloody diarrhea?

Incubation: <6 hours Source: Unrefrigerated meat/dairy (e.g., mayonnaise, cream)

What are the incubation period and source for ETEC in non-bloody diarrhea?

Incubation: 1-3 days Source: Fecal-oral transmission

What are the incubation period and source for Salmonella in non-bloody diarrhea?

Incubation: 6-48 hours Source: Eggs

What are the incubation period and source for Bacillus cereus in non-bloody diarrhea?

Incubation: 6-24 hours Source: Rice

What are the incubation period and source for Vibrio cholerae in non-bloody diarrhea?

Incubation: 6 hours to 4 days Source: Seafood, shellfish

What are the incubation period and source for EIEC/EHEC in bloody diarrhea?

Incubation: 1-9 days Source: Cattle

What are the incubation period and source for Shigella in bloody diarrhea?

Incubation: 1-6 days Source: Poultry

What are the incubation period and source for Entamoeba histolytica in bloody diarrhea?

Incubation: 1-4 weeks Source: Fecal-oral transmission

What are the incubation period and source for Campylobacter jejuni in bloody diarrhea?

Incubation: 1-10 days Source: Cattle, poultry, rodents, wild birds, household pets (dogs, cats)

What are the incubation period and source for Salmonella in bloody diarrhea?

Incubation: 6-48 hours Source: Eggs

What are the incubation period and source for Yersinia enterocolitica in bloody diarrhea?

Incubation: 1-14 days Source: Undercooked pork

What are the incubation period and source for Yersinia enterocolitica in bloody diarrhea?

Incubation: 1-14 days Source: Undercooked pork

What are the recommended antibiotics for infectious diarrhea?

Viral: None Bacterial: Fluoroquinolones, macrolides Parasitic: Metronidazole

What are the general management principles for diarrhea?

Hydration Fasting Soft diet Antibiotics if severe diarrhea persists >48 hours

What is the most common cause of acute diarrhea in children worldwide?

Rotavirus ## Footnote Rotavirus is a leading cause of severe diarrhea in children <5 years, preventable by vaccination (e.g., Rotarix, RotaTeq).

What is the hallmark clinical feature of Vibrio cholerae infection?

Profuse, watery "rice-water" diarrhea ## Footnote Leads to severe dehydration; treated with oral rehydration solution (ORS) and antibiotics (e.g., doxycycline).

What is the primary treatment for traveler’s diarrhea caused by ETEC?

Supportive care (hydration) and, if severe, fluoroquinolones or azithromycin. ## Footnote Traveler’s diarrhea is often self-limiting; loperamide may be used for symptom relief in mild cases.

What is a key complication of EHEC infection?

Hemolytic uremic syndrome (HUS) ## Footnote EHEC (e.g., E. coli O157:H7) can cause HUS, characterized by hemolytic anemia, thrombocytopenia, and renal failure.

What is the role of oral rehydration solution (ORS) in diarrhea management?

Replaces fluid and electrolyte losses to prevent dehydration. ## Footnote WHO-recommended ORS contains glucose, sodium, potassium, and chloride in specific ratios.

What is the significance of Clostridium difficile in diarrhea?

Causes antibiotic-associated diarrhea and pseudomembranous colitis. ## Footnote Treated with vancomycin or fidaxomicin; metronidazole is less preferred.

What is the diagnostic approach for chronic diarrhea?

* History and physical exam * Stool studies (culture, ova/parasites, C. difficile toxin) * Blood tests (CBC, electrolytes, inflammatory markers) * Endoscopy if indicated (e.g., for IBD, celiac disease).

What is the role of lactase deficiency in osmotic diarrhea?

Lactase deficiency leads to unabsorbed lactose in the large intestine, causing osmotic diarrhea, bloating, and flatulence. ## Footnote lactose intolerance symptoms due to unabsorbed lactose.

Diarrhea Flashcards

(54 cards)