Differential Diagnosis
- Single most likely diagnosis
- Constipation with fecal impaction: The patient's history of mild constipation, the presence of a large amount of stool in the distal colon, and the response to laxative treatment all support this diagnosis. The air-fluid levels and mild distension of the proximal colon can be seen in severe constipation.
- Other Likely diagnoses
- Functional ileus: The presence of air-fluid levels throughout the small bowel and colon could suggest an ileus, although the patient's response to laxatives and lack of other symptoms (e.g., nausea, vomiting) make this less likely.
- Colonic pseudo-obstruction: This condition can present with similar radiographic findings and can be seen in patients without a clear mechanical obstruction.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Colorectal cancer with obstruction: Although the patient has no evidence of blood in stools and is responding to laxatives, a stricture or mass in the sigmoid colon could still be present and needs to be ruled out.
- Volvulus or intussusception: These conditions can cause obstruction and need to be considered, especially if the patient's symptoms worsen or do not fully resolve with treatment.
- Ischemic bowel: This is a less likely diagnosis given the patient's lack of abdominal pain, fever, or other symptoms, but it is a potentially life-threatening condition that should be considered.
- Rare diagnoses
- Hirschsprung's disease: This congenital condition can present in adults with chronic constipation, although it is rare.
- Chronic intestinal pseudo-obstruction: This is a rare condition characterized by recurrent episodes of intestinal obstruction without a mechanical cause.