Differential Diagnosis for Recurrent Blood in Stool

Given the patient's 20-year history of intermittent blood in stool, with 5 ml of blood on some days, and despite multiple doctor visits with no resolution, the differential diagnosis can be categorized as follows:

• Single Most Likely Diagnosis
  • Hemorrhoids: This is a common condition that can cause intermittent bleeding, especially with bowel movements. The fact that the bleeding is intermittent and the patient has had it for 20 years without significant progression or other alarming symptoms makes hemorrhoids a plausible explanation.
• Other Likely Diagnoses
  • Diverticulosis: This condition involves the formation of small, bulging pouches (diverticula) in the digestive tract. It's common in adults over 40 and can cause intermittent bleeding, although it's more typical for the bleeding to be painless and more significant in volume.
  • Anal Fissures: These are small tears in the lining of the anus, which can cause pain and bleeding during bowel movements. The intermittent nature of the bleeding could fit this diagnosis, especially if the fissures are small and not always present.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic inflammation of the gastrointestinal tract, leading to symptoms including bloody stools. However, these conditions usually present with other symptoms like diarrhea, abdominal pain, and weight loss.
• Do Not Miss Diagnoses
  • Colorectal Cancer: Although less likely given the long history without significant change, colorectal cancer must be considered, especially in patients over 40. The presence of blood in the stool, even if intermittent and small in volume, warrants investigation to rule out cancer.
  • Angiodysplasia: This condition involves the formation of abnormal blood vessels in the colon, which can bleed. It's more common in older adults and can cause intermittent, painless bleeding.
  • Infectious Colitis: Certain infections can cause inflammation of the colon, leading to bloody stools. While less likely given the chronic nature of the symptoms, it's essential to consider, especially if there have been changes in the patient's travel history, sexual practices, or exposure to contaminated food and water.
• Rare Diagnoses
  • Intussusception: A condition where a part of the intestine slides into an adjacent part, potentially causing bleeding. It's rare in adults and usually presents with more acute symptoms.
  • Meckel's Diverticulum: A congenital anomaly of the small intestine that can cause bleeding due to the presence of ectopic gastric mucosa. It's more commonly diagnosed in children but can present in adults.
  • Vascular Malformations: Abnormal formations of blood vessels in the gastrointestinal tract can cause bleeding. These are rare and might require specialized imaging for diagnosis.

Each of these diagnoses has a different set of implications for treatment and prognosis, emphasizing the importance of a thorough diagnostic workup to determine the underlying cause of the patient's symptoms.