Differential Diagnosis for Blood in Stool

The presence of blood in stool, also known as hematochezia, can be caused by a variety of conditions affecting the gastrointestinal tract. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis
  • Diverticulosis: This condition is characterized by the formation of small, bulging pouches (diverticula) in the digestive tract, most commonly in the colon. It is a common cause of painless, bright red bleeding, especially in older adults.
• Other Likely Diagnoses
  • Hemorrhoids: Swollen veins in the lowest part of the rectum or anus, which can cause bleeding, especially during bowel movements.
  • Anal Fissures: Small tears in the lining of the anus, which can cause pain and bleeding during and after bowel movements.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic inflammation and ulcers in the digestive tract, leading to bleeding.
  • Gastrointestinal Infections: Certain infections, such as those caused by bacteria, viruses, or parasites, can lead to inflammation and bleeding in the GI tract.
• Do Not Miss Diagnoses
  • Colorectal Cancer: Although less common, colorectal cancer is a critical diagnosis to consider, as it can present with bleeding, especially in older adults or those with a family history.
  • Angiodysplasia: Vascular malformations in the GI tract that can cause bleeding, often seen in older adults.
  • Ischemic Colitis: Reduced blood flow to the colon, which can cause bleeding and is more common in individuals with cardiovascular disease.
• Rare Diagnoses
  • Meckel's Diverticulum: A congenital anomaly of the small intestine that can cause bleeding, more commonly seen in children and young adults.
  • Intussusception: A condition where a part of the intestine slides into an adjacent part, which can cause bowel obstruction and bleeding, more common in children.
  • Arteriovenous Malformations (AVMs): Abnormal connections between arteries and veins that can cause bleeding in the GI tract, rare and often congenital.
  • Dieulafoy's Lesion: A rare cause of GI bleeding characterized by a small mucosal defect with an exposed, often large, caliber artery.

Each of these diagnoses has a different set of risk factors, symptoms, and diagnostic approaches. A thorough medical history, physical examination, and diagnostic tests such as endoscopy, colonoscopy, and imaging studies are crucial for determining the underlying cause of blood in stool.