Diarrhea Clinical Presentation

Updated: Jun 23, 2017
  • Author: Stefano Guandalini, MD; Chief Editor: Carmen Cuffari, MD  more...
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Acute diarrhea in developed countries is almost invariably a benign, self-limited condition, subsiding within a few days. The clinical presentation and course of illness depend on the etiology of the diarrhea and on the host. For example, rotavirus is more commonly associated with vomiting, dehydration, and a greater number of work days lost than nonrotavirus gastroenteritis.

  • A prospective study conducted in the United States in 604 children aged 3-36 months in community settings before the introduction of rotavirus vaccine found that the highest incidence of acute diarrhea was in January and August, with an overall incidence of 2.21 episodes per person-year. [8] Close to 90% of episodes were acute (ie, lasting < 14 d, with a median duration of 2 d and a median of 6 stools per day).
  • Diarrhea implies an increase in stool volume and diminished stool consistency.
    • In children younger than 2 years, diarrhea is defined as daily stools with a volume greater than 10 mL/kg.
    • In children older than 2 years, diarrhea is defined as daily stools with a weight greater than 200 g. In practice, this typically means loose-to-watery stools passed 3 or more times per day.
    • Individual stool patterns widely vary; for example, breastfed children may normally have 5-6 stools per day.
  • Flatulence associated with foul-smelling stools that float suggests fat malabsorption, which can be observed with infection with Giardia lamblia.
  • Knowledge of the characteristics of consistency, color, volume, and frequency can be helpful in determining whether the source is from the small or large bowel. Table 1 outlines these characteristics and demonstrates that an index of suspicion can be easily generated for a specific set of organisms.

Table 1. Stool Characteristics and Determining Their Source (Open Table in a new window)

Stool Characteristics Small Bowel Large Bowel
Appearance Watery Mucoid and/or bloody
Volume Large Small
Frequency Increased Highly increased
Blood Possibly positive but never gross blood Commonly grossly bloody
pH Possibly < 5.5 >5.5
Reducing substances Possibly positive Negative
WBCs < 5/high power field Commonly >10/high power field
Serum WBCs Normal Possible leukocytosis, bandemia
Organisms Viral
  • Rotavirus
  • Adenovirus
  • Calicivirus
  • Astrovirus
  • Norovirus
Invasive bacteria
  • Escherichia Coli (enteroinvasive, enterohemorrhagic)
  • Shigella species
  • Salmonella species
  • Campylobacter species
  • Yersinia species
  • Aeromonas species
  • Plesiomonas species
Enterotoxigenic bacteria
  • E coli
  • Klebsiella
  • Clostridium perfringens
  • Cholera species
  • Vibrio species
Toxic bacteria
  • Clostridium difficile
  • Giardia species
  • Cryptosporidium species
  • Entamoeba organisms

See the list below:

  • Associated systemic symptoms include the following:
    • Some enteric infections commonly have systemic symptoms, whereas others less commonly are associated with systemic features.
    • Table 2 outlines the frequency of some of these symptoms with particular organisms. It also outlines incubation periods and usual duration of symptoms of common organisms. Certain organisms (eg, C difficile, Giardia, Entamoeba species) may be associated with a protracted course.

Table 2. Organisms and Frequency of Symptoms (Open Table in a new window)

Organism Incubation Duration Vomiting Fever Abdominal Pain
Rotavirus 1-7 d 4-8 d Yes Low No
Adenovirus 8-10 d 5-12 d Delayed Low No
Norovirus 1-2 d 2 d Yes No No
Astrovirus 1-2 d 4-8 d +/- +/- No
Calicivirus 1-4 d 4-8 d Yes +/- No
Aeromonas species None 0-2 wk +/- +/- No
Campylobacter species 2-4 d 5-7 d No Yes Yes
C difficile Variable Variable No Few Few
C perfringens Minimal 1 d Mild No Yes
Enterohemorrhagic E coli 1-8 d 3-6 d No +/- Yes
Enterotoxigenic E coli 1-3 d 3-5 d Yes Low Yes
Plesiomonas species None 0-2 wk +/- +/- +/-
Salmonella species 0-3 d 2-7 d Yes Yes Yes
Shigella species 0-2 d 2-5 d No High Yes
Vibrio species 0-1 d 5-7 d Yes No Yes
Y enterocolitica None 1-46 d Yes Yes Yes
Giardia species 2 wk 1+ wk No No Yes
Cryptosporidium species 5-21 d Months No Low Yes
Entamoeba species 5-7 d 1-2+ wk No Yes No

See the list below:

  • Daycare considerations are as follows:
    • Certain organisms are spread quickly in daycare. These organisms include rotavirus; astrovirus; calicivirus; and Campylobacter, Shigella, Giardia, and Cryptosporidium species.
    • Increase in daycare usage has raised the incidence of rotavirus and Cryptosporidium species.
  • Food history can be helpful.
    • Ingestion of raw or contaminated food is a common cause of infectious diarrhea.
    • Organisms that cause food poisoning include the following:
      • Dairy food -Campylobacter and Salmonella species
      • Eggs -Salmonella species
      • Meats -C perfringens and Aeromonas, Campylobacter, and Salmonella species
      • Ground beef - Enterohemorrhagic E coli
      • Poultry -Campylobacter species
      • Pork -C perfringens, Y enterocolitica
      • Seafood - Astrovirus and Aeromonas, Plesiomonas, and Vibrio species
      • Oysters - Calicivirus and Plesiomonas and Vibrio species
      • Vegetables -Aeromonas species and C perfringens
    • Guidelines on fruit juice intake for children by the American Academy of Pediatrics recommend that in the evaluation of children with chronic diarrhea, excessive flatulence, abdominal pain, and bloating, the pediatrician should determine the amount of juice being consumed. [9]
  • Water exposure can contribute to diarrhea.
    • Water is a major reservoir for many organisms that cause diarrhea.
    • Swimming pools have been associated with outbreaks of infection with Shigella species; Aeromonas organisms are associated with exposure to the marine environment.
    • Giardia, Cryptosporidium, and Entamoeba organisms are resistant to water chlorination; therefore, exposure to contaminated water should raise index of suspicion for these parasites.
  • A history of camping suggests exposure to water sources contaminated with Giardia organisms.
  • Travel history may indicate a cause for diarrhea.
    • Enterotoxigenic E coli is the leading cause of traveler's diarrhea.
    • Rotavirus and Shigella, Salmonella, and Campylobacter organisms are prevalent worldwide and need to be considered regardless of specific travel history.
    • Risk of contracting diarrhea while traveling is, by far, highest for persons traveling to Africa.
    • Travel to Central and South America and Eastern European countries is also associated with a relatively high risk of contracting diarrhea.
    • Other organisms that are prevalent in particular parts of the world include the following:
      • Nonspecific foreign travel history - Enterotoxigenic E coli and Aeromonas, Giardia, Plesiomonas, Salmonella, and Shigella species
      • Underdeveloped tropical visit -C perfringens
      • Travel to Africa -Entamoeba species, Vibrio cholerae
      • Travel to South America and Central America -Entamoeba species, V cholerae, enterotoxigenic E coli
      • Travel to Asia -V cholerae
      • Travel to Australia -Yersinia species
      • Travel to Canada -Yersinia species
      • Travel to Europe -Yersinia species
      • Travel to India -Entamoeba species, V cholerae
      • Travel to Japan -Vibrio parahaemolyticus
      • Travel to Mexico -Aeromonas, Entamoeba, Plesiomonas, and Yersinia species
      • New Guinea -Clostridium species
  • Animal exposure can contribute to diarrhea.
    • Exposure to young dogs or cats is associated with Campylobacter organisms.
    • Exposure to turtles is associated with Salmonella organisms.
  • Certain medical conditions predispose patients to infection, including the following:
    • C difficile - Hospitalization, antibiotic administration
    • Plesiomonas species - Liver diseases or malignancy
    • Salmonella species - Intestinal dysmotility, malnutrition, achlorhydria, hemolytic anemia (especially sickle cell disease), immunosuppression, malaria
    • Rotavirus - Hospitalization
    • Giardia species -Agammaglobulinemia, chronic pancreatitis, achlorhydria, cystic fibrosis
    • Cryptosporidia species - Immunocompromised or immunosuppressed state


The following may be observed:

  • Dehydration
    • Dehydration is the principal cause of morbidity and mortality.
    • Assess every patient with diarrhea for signs, symptoms, and severity.
    • Lethargy, depressed consciousness, sunken anterior fontanel, dry mucous membranes, sunken eyes, lack of tears, poor skin turgor, and delayed capillary refill are obvious and important signs of dehydration. Table 3 below details dehydration severity and symptoms.

Table 3. Dehydration Severity, Signs, and Symptoms (Open Table in a new window)

Hydration 0-5% Dehydration


5-10% Dehydration


10% or More


General Well Restless Lethargic
Eyes Normal Sunken Very sunken
Tears Present Absent Absent
Mouth Moist Dry Very dry
Thirst Drinks normally Thirsty Drinks poorly
Skin Pinch retracts immediately Pinch retracts slowly Pinch stays folded


See the list below:

  • Failure to thrive and malnutrition
    • Reduced muscle and fat mass or peripheral edema may be clues to the presence of carbohydrate, fat, and/or protein malabsorption.
    • Giardia organisms can cause intermittent diarrhea and fat malabsorption.
  • Abdominal pain
    • Nonspecific nonfocal abdominal pain and cramping are common with some organisms.
    • Pain usually does not increase with palpation.
    • With focal abdominal pain worsened by palpation, rebound tenderness, or guarding, be alert for possible complications or for another noninfectious diagnosis.
  • Borborygmi: Significant increases in peristaltic activity can cause an audible and/or palpable increase in bowel activity.
  • Perianal erythema
    • Frequent stools can cause perianal skin breakdown, particularly in young children.
    • Secondary carbohydrate malabsorption often results in acidic stools.
    • Secondary bile acid malabsorption can result in a severe diaper dermatitis that is often characterized as a "burn."


Although infectious agents are by far the most common cause for sporadic or endemic episodes of acute diarrhea, one should not dismiss other causes that can lead to the same presentation.

  • Causes of diarrhea with acute onset include the following:
    • Infections
      • Enteric infections (including food poisoning
      • Extraintestinal infections
    • Drug-induced
      • Antibiotic-associated
      • Laxatives
      • Antacids that contain magnesium
      • Opiate withdrawal
      • Other drugs
    • Food allergies or intolerances
      • Cow's milk protein allergy
      • Soy protein allergy
      • Multiple food allergies
      • Olestra
      • Methylxanthines (caffeine, theobromine, theophylline)
    • Disorders of digestive/absorptive processes
      • Glucose-galactose malabsorption
      • Sucrase-isomaltase deficiency
      • Late-onset (adult-type) hypolactasia, resulting in lactose intolerance
    • Chemotherapy or radiation-induced enteritis
    • Surgical conditions
    • Vitamin deficiencies
      • Niacin deficiency
      • Folate deficiency
    • Vitamin toxicity
      • Vitamin C
      • Niacin, vitamin B3
    • Ingestion of heavy metals or toxins (eg, copper, tin, zinc)
    • Ingestion of plants (eg, hyacinths, daffodils, azalea, mistletoe, Amanita species mushrooms
  • Infectious causes of acute diarrhea in developed countries
    • Viruses
      • Rotavirus - 25-40% of cases
      • Norovirus - 10-20% of cases
      • Calicivirus - 1-20% of cases
      • Astrovirus - 4-9% of cases
      • Enteric-type adenovirus - 2-4% of cases
    • Bacteria
      • Campylobacter jejuni - 6-8% of cases
      • Salmonella - 3-7% of cases
      • E Coli - 3-5% of cases
      • Shigella - 0-3% of cases
      • Y enterocolitica - 1-2% of cases
      • C difficile - 0-2% of cases
      • Vibrio parahaemolyticus - 0-1% of cases
      • V cholerae - Unknown
      • Aeromonas hydrophila - 0-2% of cases
    • Parasites
      • Cryptosporidium - 1-3% of cases
      • G lamblia - 1-3% of cases

A study by Yi et al of 207 stool samples from hospitalized children in metropolitan Atlanta, Ga, with health-care–associated vomiting and/or diarrhea found that 20 children (10%) were positive for rotavirus and 7 children (3%) were positive for norovirus. The results indicated that these pathogens have an important role in pediatric nosocomial illness. [10]