Differential Diagnosis for Patient with Proctocolitis, Fecal Impaction, Pulmonary Embolism, and Rectal Bleeding on Apixaban

• Single Most Likely Diagnosis:
  • Apixaban-induced bleeding: The patient is on apixaban, a direct oral anticoagulant (DOAC), which increases the risk of bleeding, especially in the context of a pre-existing condition like proctocolitis. The recent onset of rectal bleeding after starting apixaban strongly suggests that the medication is the cause of the bleeding.
• Other Likely Diagnoses:
  • Hemorrhoids or anal fissures: These conditions are common and can cause rectal bleeding, especially in the setting of fecal impaction which can lead to straining during bowel movements.
  • Proctocolitis exacerbation: The patient's underlying proctocolitis could be exacerbating, leading to increased inflammation and bleeding in the rectum.
• Do Not Miss Diagnoses:
  • Lower gastrointestinal malignancy: Although less likely, it's crucial not to miss a potential malignancy, such as colorectal cancer, which could present with rectal bleeding.
  • Infectious colitis: Certain infections can cause severe colitis and rectal bleeding, and missing this diagnosis could lead to severe consequences if not treated promptly.
  • Ischemic colitis: This condition, which involves insufficient blood flow to the colon, can cause rectal bleeding and is important not to miss due to its potential for serious complications.
• Rare Diagnoses:
  • Vasculitis: Conditions like vasculitis can cause rectal bleeding but are less common and would typically be associated with other systemic symptoms.
  • Angiodysplasia: This is a rare condition involving vascular malformations in the gastrointestinal tract that can cause bleeding, more commonly seen in the elderly.
  • Coagulopathy: An underlying coagulopathy could contribute to the bleeding, although the patient is already on an anticoagulant, making this less likely as a primary cause.

Management

The management of this patient should focus on addressing the rectal bleeding, managing the anticoagulation therapy, and treating the underlying proctocolitis and fecal impaction. This may involve:

• Temporarily holding or reversing the anticoagulant if the bleeding is severe.
• Endoscopic evaluation to identify and potentially treat the source of bleeding.
• Treatment of the proctocolitis, which may involve medications to reduce inflammation.
• Measures to prevent further fecal impaction, such as stool softeners and increased fluid intake.
• Monitoring for signs of further bleeding or complications from the pulmonary embolism.