Differential Diagnosis for Acute Diarrhea
Single Most Likely Diagnosis
- Viral Gastroenteritis: This is the most common cause of acute diarrhea, often due to norovirus or rotavirus, and is usually self-limiting. The justification for this being the single most likely diagnosis is its high prevalence and the fact that it can affect anyone, regardless of age or health status.
Other Likely Diagnoses
- Bacterial Gastroenteritis: Caused by bacteria such as Salmonella, Shigella, or Campylobacter, often related to food or water contamination. This is a common cause of acute diarrhea, especially in individuals who have recently traveled or consumed undercooked food.
- Food Poisoning: Similar to bacterial gastroenteritis but often implies a more immediate onset after ingestion of contaminated food. Common culprits include Staphylococcus aureus and Bacillus cereus.
- Medication-Induced Diarrhea: Certain medications, such as antibiotics, can cause diarrhea as a side effect. This is particularly likely in patients who have recently started a new medication.
Do Not Miss Diagnoses
- Clostridioides difficile (C. diff) Infection: Although not the most common cause, C. diff can lead to severe diarrhea and life-threatening complications, especially in hospitalized patients or those with recent antibiotic use. Missing this diagnosis could have severe consequences.
- Inflammatory Bowel Disease (IBD) Flare: While less common, an acute flare of IBD (Crohn's disease or ulcerative colitis) can present with severe diarrhea and requires prompt recognition and treatment to prevent complications.
- Intestinal Ischemia: A rare but potentially life-threatening condition where blood flow to the intestines is compromised, leading to acute diarrhea among other symptoms.
Rare Diagnoses
- Cholera: Caused by Vibrio cholerae, this is rare in developed countries but can occur in travelers to endemic areas. It presents with profuse, watery diarrhea.
- Giardiasis: An intestinal infection caused by the parasite Giardia lamblia, more common in travelers to certain regions or in individuals with exposure to contaminated water.
- Whipple's Disease: A rare, systemic bacterial infection (Tropheryma whipplei) that can cause chronic diarrhea among other symptoms, often presenting with malabsorption and weight loss.