Differential Diagnosis for Black Stool with Occult Negative

• Single most likely diagnosis:
  • Peptic ulcer disease (PUD) with bleeding that has stopped or is intermittent: This is a common cause of black stools due to the digestion of blood in the gastrointestinal tract. The occult negative test suggests that the bleeding may have stopped or is not active at the time of testing.
• Other Likely diagnoses:
  • Gastroesophageal reflux disease (GERD) with bleeding: Similar to PUD, GERD can cause bleeding in the upper GI tract, leading to black stools.
  • Gastritis: Inflammation of the stomach lining can cause bleeding, resulting in black stools.
  • Use of medications or supplements that can cause black stools (e.g., iron supplements, bismuth subsalicylate): Certain medications and supplements can cause black stools due to their color or effect on the GI tract.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Upper GI malignancy (e.g., gastric cancer): Although less common, upper GI malignancies can cause bleeding and black stools. Missing this diagnosis could be fatal.
  • Variceal bleeding: Bleeding from esophageal varices can cause black stools and is a life-threatening condition.
  • Aorticenteric fistula: A rare but potentially life-threatening condition where there is a fistula between the aorta and the intestine, causing bleeding and black stools.
• Rare diagnoses:
  • Hemobilia: Bleeding from the biliary tree can cause black stools, but this is a rare condition.
  • Hematochezia from a small bowel source: Bleeding from the small bowel can cause black stools, but this is less common than upper GI sources.
  • Intussusception: A rare condition where a part of the intestine telescopes into another part, causing bleeding and potentially black stools.