Updated: 10/13/2019

Diarrhea

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Questions
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Evidence
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Topic
Snapshot
  • A 25-year-old man presents to his primary care physician for evaluation of diarrhea. He had recently gone to Mexico for spring break, where he stayed in a hostel with his friends. He spent a lot of time on the beach, swimming in caves, and hiking. He reports having onset of watery diarrhea about a week ago. He has not had any fevers, nausea, or vomiting. He does recall eating multiple rounds of raw oysters while in Mexico. He is found to be dehydrated, with poor skin turgor and dry mucous membrane.
Introduction
  • Overview
    • acute diarrhea is characterized by acute onset of >3 bowel movements/day lasting <14 days and is often caused by infection
    • persistent diarrhea lasts 2-4 weeks
    • chronic diarrhea lasts >4 weeks and is often caused by underlying conditions such as inflammatory bowel disease or fat malabsorption
  • Epidemiology
    • incidence
      • very common
      • rotavirus is most common cause of infectious diarrhea worldwide
        • vaccine available
      • acute diarrhea is the second cause of childhood mortality in the world
    • demographics
      • viral diarrhea is most common in children
        • especially rotavirus and adenovirus
  • Etiology
    • infections
      • viruses
      • bacteria
      • parasites
    • drug-induced
      • quinidine
      • colchicine
      • cytotoxic agents
      • chemotherapy
    • food allergies
    • toxic ingestions
    • autoimmun
    • small intestine bacterial overgrowth, often secondary to scleroderma or diabetes
  • Pathogenesis
    • types of diarrhea
      • exudative/inflammatory diarrhea
        • frequent, small-volume, and bloody stools
        • indicates disrupted and inflamed mucosa
        • etiologies
          • infectious (i.e., Shigella, Salmonella, E. coli, Campylobacter, amebiasis)
          • idiopathic inflammatory bowel disease (ulcerative colitis, Crohn disease)
          • ischemic colitis
      • fatty diarrhea
        • weight loss and greasy or bulky stools that float that are often chronic
        • etiologies
          • fat malabsorption
      • watery diarrhea
        • osmotic diarrhea
          • due to osmotic pull of water into the intestinal lumen
          • etiologies
            • giardiasis
            • laxatives
            • lactose intolerance
        • secretory diarrhea
          • due to active secretion of water
          • etiologies
            • infectious (i.e., enterotoxic E. coli, Vibrio)
            • carcinoid syndrome
            • gastrinoma
            • drugs (i.e., colchicine)
 
Infectious Bloody vs Watery Diarrhea
Bloody Diarrhea
Watery Diarrhea
  • Campylobacter
  • E. histolytica
  • Enterohemorrhagic E. coli
  • Enteroinvasive E. coli
  • Non-thypoidal Salmonella
  • Shigella
  • Y. enterocolitica
  • C. difficile
  • C. perfringens
  • Enterotoxigenic E. coli
  • Giardia
  • Cryptosporidium
  • V. cholerae
  • Rotavirus
  • Norovirus
  • Adenovirus
  • S. aureus
 
High Yield Risk Factors
Exposure Risk Factors
Associated Organisms
Daycare
  • Rotavirus, astrovirus, calicivirus, Campylobacter, Shigella, Giardia, Cryptosporidium
Food       
  • Dairy
  • Campylobacter, Salmonella
  • Eggs
  • Salmonella
  • Beef
  • E. coli
  • Poultry
  • Campylobacter, Salmonella
  • Pork
  • C. perfringens, Y. enterocolitica
  • Seafood
  • Astrovirus, Vibrio
  • Oysters
  • Calicivirus, Vibrio
  • Rice/pasta
  • Bacillus cereus
Water exposure 
  • Swimming pools
  • Shigella
  • Contaminated water with cysts
  • Giardia, E. histolytica, Cryptosporidium
Travel history 
  • "Traveler's" diarrhea
  • E. coli, Giardia, Salmonella, Shigella, Campylobacter
  • Camping/hiking
  • Giardia
Past medical history
  • Antibiotics/hospitalization
  • C. difficile, rotavirus
Pets  
  • Dog feces
  • Yersinia enterocolitica
  • Turtles/reptiles
  • Non-typhoidal Salmonella
  • Other animals/pets
  • Campylobacter
 
Presentation
  • Symptoms
    • common symptoms
      • dehydration
        • lethargy
        • feeling of thirst
      • diarrhea
        • foul-smelling along with stools that float
        • bloody diarrhea
        • watery diarrhea 
      • other enteric symptoms
        • nausea
        • vomiting
        • abdominal pain/cramping
  • Physical exam
    • inspection
      • dry mucous membranes
      • sunken eyes
      • poor skin turgor
      • delayed capillary refill
Studies
  • Acute diarrhea does not routinely require laboratory evaluation, unless clinical presentation includes
    • high fever
    • bloody diarrhea
    • severe abdominal pain
    • requires hospitalization
    • elderly
    • immunocompromised status
  • Serum labs
    • complete blood count
  • Stool studies
    • ova and parasite examination
    • C. difficile toxin
    • leukocyte presence suggests enteroinvasive infection
    • pH <5.5 usually indicates viral illness and can also indicate lactase deficiency
    • culture
    • enzyme immunoassay for rotavirus and adenovirus antigens
    • latex agglutination assay for rotavirus
Differential
  • Chronic diarrhea, which lasts 4 weeks or more, suggests other etiologies, such as fat malabsorption syndrome
 
Chronic Diarrhea
  • Malabsorption syndromes
  • Celiac disease
  • Lactose intolerance
  • Pancreatic insufficiency
  • Diabetic neuropathy
  • Inflammatory bowel disease
  • Crohn disease
  • Ulcerative colitis
  • Other gastrointestinal causes
  • Microscopic colitis
  • Irritable bowel syndrome
  • Endocrinological
  • Carcinoid
  • Gastrinoma
  • Drug-induced
  • Quinidine
  • Colchicine
  • Chemotherapy
  • Other
  • Severe combined immunodeficiency
  • Arsenic poisoning
  • Vitamin C toxicity
  • Vitamin B3 deficiency
 
Treatment
  • Medical
    • supportive care
      • modalities
        • oral rehydration
        • intravenous rehydration
        • electrolyte repletion
    • antibiotics
      • indication
        • for bacterial etiologies causing moderate or severe diarrhea and not responsive to rehydration
        • metronidazole or tinidazole for Giardia infections 
        • doxycycline for Vibrio cholera
        • oral vancomycin for C. difficile infection 
    • anti-motility agents
      • indication
        • not indicated for infectious diarrhea
      • modalities
        • loperamide
        • bismuth salicylate
Complications
  • Dehydration

Please rate topic.

Average 4.4 of 5 Ratings

Questions (3)

(M1.GI.13.80) A 22-year-old female presents to your office with gas, abdominal distention, and explosive diarrhea. She normally enjoys eating cheese but has been experiencing these symptoms after eating it for the past few months. She has otherwise been entirely well except for a few days of nausea, diarrhea, and vomiting earlier in the year from which she recovered without treatment. Which of the following laboratory findings would you expect to find during workup of this patient?

QID: 101137
1

Decreased stool osmolar gap

14%

(15/106)

2

Decreased stool pH

65%

(69/106)

3

Positive fecal smear for leukocytes

8%

(8/106)

4

Positive stool culture for Rotavirus

4%

(4/106)

5

Positive stool culture for T. whippelii

8%

(9/106)

M 2 E

Select Answer to see Preferred Response

(M1.GI.13.100) A 30-year-old male visits you in the clinic complaining of chronic abdominal pain and diarrhea following milk intake. Gastrointestinal histology of this patient's condition is most similar to which of the following?

QID: 101157
1

Celiac disease

16%

(18/115)

2

Crohns disease

0%

(0/115)

3

Tropical sprue

3%

(4/115)

4

No GI disease

77%

(89/115)

5

Ulcerative colitis

2%

(2/115)

M 1 E

Select Answer to see Preferred Response

(M1.GI.13.7) A 24-year-old patient presents to your gastroenterology practice on a referral from her primary care provider. The patient has been experiencing postprandial bloating and abdominal pain for one year. Symptoms occur following the ingestion of milk products. Which of the following drugs has a mechanism of action that is similar to the pathophysiology of this patient's disease?

QID: 101064
1

Omeprazole

4%

(10/250)

2

Bismuth

10%

(24/250)

3

Ranitidine

6%

(15/250)

4

Octreotide

11%

(27/250)

5

Magnesium hydroxide

66%

(166/250)

M 3 E

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Evidence (5)
EXPERT COMMENTS (6)
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