Differential Diagnosis for Hematochezia in a 79-year-old Woman
- Single most likely diagnosis
- Ischemic colitis: This is the most likely cause given the patient's recent myocardial infarction, atrial fibrillation, and presentation with abdominal pain, hypotension, and bloody bowel movement. Ischemic colitis occurs when there is an interruption or reduction of blood flow to the colon, which can be caused by emboli (more common in atrial fibrillation) or other factors leading to hypoperfusion, such as the patient's current hypotensive state.
- Other Likely diagnoses
- Diverticulitis: While diverticulitis can cause abdominal pain and potentially bleeding, the presence of bloody bowel movement in the context of this patient's cardiovascular history and hemodynamic instability makes ischemic colitis more likely. However, diverticulitis remains a consideration, especially with left lower quadrant tenderness.
- Platelet inhibition: The patient is on apixaban, an anticoagulant, which increases the risk of bleeding. However, the primary issue here seems to be related to the gastrointestinal tract rather than a systemic bleeding disorder. The anticoagulation could exacerbate bleeding from any gastrointestinal source but is less likely the primary cause of her hematochezia.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Sigmoid volvulus: Although less common and not as directly linked to her current presentation as ischemic colitis, sigmoid volvulus is a surgical emergency that can cause ischemia and necrosis of the bowel if not promptly addressed. It typically presents with abdominal pain, distension, and obstipation, but can also lead to bloody stools if the bowel becomes ischemic.
- Rare diagnoses
- Other rare causes of hematochezia, such as angiodysplasia, vascular malformations, or even a gastrointestinal malignancy, are less likely given the acute presentation and the patient's specific risk factors for ischemic events. However, these could be considered if initial evaluations for more likely causes are negative.