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: Lactose intolerance, gluten intolerance (celiac disease), or fructose malabsorption can lead to chronic or recurrent diarrhea.
  • Medication-induced Diarrhea: Certain medications, including antibiotics, antacids, and blood pressure medications, can cause diarrhea as a side effect.
• 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 in individuals who have recently used antibiotics.
  • Giardiasis: An intestinal infection caused by the parasite Giardia lamblia, which can lead to severe and prolonged diarrhea if not treated.
• Rare Diagnoses
  • Microscopic Colitis: A condition characterized by inflammation of the colon lining, which can cause chronic, watery diarrhea.
  • Whipple's Disease: A rare, systemic bacterial infection that can cause diarrhea, among other symptoms, and requires early diagnosis for effective treatment.
  • Carcinoid Syndrome: A rare condition caused by a neuroendocrine tumor that can lead to chronic diarrhea, flushing, and other symptoms.