Diarrhea Differential Diagnosis

The differential diagnosis for diarrhea can be organized into the following categories:

• Single Most Likely Diagnosis
  • Viral gastroenteritis: This is the most common cause of diarrhea, often caused by norovirus or rotavirus, and is usually self-limiting.
• Other Likely Diagnoses
  • Bacterial gastroenteritis (e.g., Salmonella, E. coli, Campylobacter): These infections can cause diarrhea and are often foodborne or waterborne.
  • Food intolerance (e.g., lactose intolerance): Some individuals may experience diarrhea due to an inability to digest certain nutrients.
  • Inflammatory bowel disease (e.g., Crohn's disease, ulcerative colitis): Chronic conditions that cause inflammation in the digestive tract, leading to diarrhea.
  • Irritable bowel syndrome (IBS): A functional disorder that can cause diarrhea, abdominal pain, and changes in bowel habits.
• Do Not Miss Diagnoses
  • Clostridioides difficile (C. diff) infection: A potentially life-threatening condition that can cause severe diarrhea, especially in individuals who have taken antibiotics.
  • Giardiasis: An intestinal infection caused by the Giardia parasite, which can lead to severe diarrhea and dehydration if left untreated.
  • Intestinal obstruction or ischemia: Conditions that can cause severe abdominal pain and diarrhea, requiring prompt medical attention.
• Rare Diagnoses
  • Whipple's disease: A rare, systemic bacterial infection that can cause diarrhea, weight loss, and abdominal pain.
  • Tropical sprue: A rare condition that affects the small intestine, causing diarrhea, weight loss, and malabsorption.
  • Carcinoid syndrome: A rare condition caused by a neuroendocrine tumor, which can lead to diarrhea, flushing, and wheezing.
  • Short bowel syndrome: A rare condition that occurs when a large portion of the small intestine is removed or not functioning, leading to severe diarrhea and malabsorption.