Differential Diagnosis for Diarrhea

• Single Most Likely Diagnosis
  • Viral gastroenteritis: This is the most common cause of diarrhea, often resulting from viral infections such as norovirus or rotavirus, which are highly contagious and can spread through contaminated food, water, or close contact with an infected person.
• Other Likely Diagnoses
  • Bacterial gastroenteritis: Caused by bacteria like Salmonella, E. coli, or Campylobacter, often from consuming contaminated food or water.
  • Food intolerance: Conditions like lactose intolerance can lead to diarrhea after consuming specific foods.
  • Irritable Bowel Syndrome (IBS): A chronic condition characterized by recurring abdominal pain and changes in bowel movements, including diarrhea.
• Do Not Miss Diagnoses
  • Inflammatory bowel disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic diarrhea and require early diagnosis for proper management.
  • Clostridioides difficile (C. diff) infection: A potentially life-threatening condition that can cause severe diarrhea, especially after antibiotic use.
  • Giardiasis: An intestinal infection caused by the parasite Giardia lamblia, which can lead to severe and prolonged diarrhea if not treated.
• Rare Diagnoses
  • Whipple's disease: A rare, systemic bacterial infection that can cause chronic diarrhea among other symptoms.
  • Microscopic colitis: A condition characterized by inflammation of the colon that can cause chronic, watery diarrhea.
  • Thyrotoxicosis: Although rare, hyperthyroidism can cause diarrhea as one of its many symptoms due to increased motility of the gastrointestinal tract.