Diarrhea is a change in normal bowel movements characterized by increased frequency, water content or volume of stools.
Infectious diarrhea is diarrhea of infectious origin (bacteria, virus, protozoal) and is usually associated with symptoms of nausea and vomiting and abdominal cramps.
Dysentery (invasive diarrhea) has the presence of visible blood in diarrheic stool.


  • Diarrhea: Change in normal bowel movements characterized by increase in frequency, water content or volume of stools
    • ≥3 episodes/day or at least 250 g/stool per day
  •  Acute diarrhea: Diarrhea lasting <14 days duration
  • Persistent diarrhea: Diarrhea lasting ≥14 days
  • Chronic diarrhea: Diarrhea lasting ≥30 days
  • Infectious diarrhea: Diarrhea of infectious origin (bacterial, viral, protozoal) and is usually associated with symptoms of nausea and vomiting (N/V) and abdominal cramps
  • Dysentery (Invasive diarrhea): Presence of visible blood in diarrheic stool

Signs and Symptoms

  • Determine abrupt or gradual onset, duration and progression of symptoms
  • Onset and frequency of bowel movement
  • Amount of stool excreted
  • If dysenteric symptoms are present (eg fever, tenesmus, blood/pus in stool)

Associated Symptoms

  • Frequency and intensity of N/V, abdominal pain, cramps, myalgia, headache, altered sensorium

Stool Characteristics

  • Watery, bloody, mucus, purulent, greasy

Symptoms of Volume Depletion

  • Thirst
  • Tachycardia
  • Orthostasis
  • Decreased urination
  • Decrease in skin turgor
  • Lethargy

Risk Factors

Epidemiological Risk Factors

  • Place of residence
  • Travel to developing country
  • Daycare attendance, employment
  • Ingestion of unsafe foods (eg raw meats, eggs, shellfish, etc)
  • Swimming/drinking untreated fresh water
  • Visit to farm or contact with pets with diarrhea
  • Contact with other ill persons
  • Recent or regular medications (eg antibiotics, antacids, antimotility agents)
  • Underlying medical conditions [acute immunodeficiency syndrome (AIDS), immunosuppressants, elderly]
  • Receptive anal or oral-anal sexual contact
  • Occupation as food-handler or caregiver
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