Differential Diagnosis
- Single most likely diagnosis
- Colorectal cancer: The patient's age, smoking history, and symptoms of pain and inability to pass bowel movements, combined with the CT finding of colon narrowing, make colorectal cancer a highly likely diagnosis. The fact that the patient can still pass gas suggests a partial obstruction, which is consistent with a tumor.
- Other Likely diagnoses
- Diverticulitis: The patient's age and symptoms of pain and constipation could be consistent with diverticulitis, especially if the narrowing of the colon is due to inflammation.
- Colon stricture: A stricture could cause the symptoms of obstruction and narrowing seen on CT. This could be due to a variety of causes, including ischemia, inflammation, or previous surgery.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Volvulus: Although less likely, a volvulus (twisting of the colon) could cause obstruction and narrowing, and is a surgical emergency.
- Ischemic colitis: This condition could cause narrowing and obstruction due to decreased blood flow to the colon, and is a serious condition that requires prompt treatment.
- Intussusception: This is a condition where one part of the intestine telescopes into another, causing obstruction. It is rare in adults, but can be a surgical emergency.
- Rare diagnoses
- Lymphoma: A rare cause of colon narrowing and obstruction, but could be considered in the differential diagnosis, especially if other symptoms such as weight loss or night sweats are present.
- Carcinoid tumor: A rare tumor that could cause colon narrowing and obstruction, often with other symptoms such as flushing or diarrhea.
- Inflammatory bowel disease (IBD): Although IBD is more common in younger patients, it could still be a consideration in this patient, especially if there is a history of chronic diarrhea or other symptoms consistent with IBD.