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.
  • Medication side effects: Certain medications, such as antibiotics or antacids, can cause diarrhea as a side effect.
  • 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 or ulcerative colitis, which can cause chronic diarrhea and have significant long-term implications if not treated.
  • Clostridioides difficile (C. diff) infection: A bacterial infection that can cause severe diarrhea, especially after antibiotic use, and can be life-threatening if not properly managed.
  • Giardiasis: An intestinal infection caused by the parasite Giardia lamblia, which can lead to severe diarrhea and dehydration if not treated.
• Rare Diagnoses
  • Whipple's disease: A rare, systemic bacterial infection that can cause diarrhea, among other symptoms.
  • Tropical sprue: A rare condition that affects the small intestine's ability to absorb nutrients, leading to chronic diarrhea, typically seen in people who have spent time in tropical regions.
  • Microscopic colitis: A condition characterized by inflammation of the colon, leading to chronic, watery diarrhea, often in older adults.