Differential Diagnosis
- Single most likely diagnosis
- Fecal impaction: The patient's history of mild constipation, recent onset of severe constipation, and inability to pass stool, along with the CT scan findings of a large amount of stool in the distal colon, support this diagnosis. The patient's response to laxatives and normal bowel movements after treatment also suggest fecal impaction.
- Other Likely diagnoses
- Constipation-induced ileus: The patient's symptoms and CT scan findings, including air-fluid levels and proximal colon distension, could also be consistent with an ileus caused by constipation.
- Dehydration-induced constipation: The patient's admission of poor hydration in the days leading up to the onset of constipation, along with the consumption of constipating foods, supports this diagnosis.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Intestinal obstruction: Although the CT scan suggests that an underlying stricture or mass would not be excluded, the patient's response to laxatives and lack of other symptoms make this less likely. However, intestinal obstruction is a potentially life-threatening condition that must be considered.
- Colorectal cancer: Despite the patient's lack of family history, colorectal cancer is a possible cause of constipation and fecal impaction, especially in a 61-year-old male. The area of narrowing in the sigmoid colon could be a stricture or mass.
- Medication-induced constipation: The patient's use of opioid pain medication and methamphetamine could contribute to constipation, and it is essential to consider the potential side effects of these medications.
- Rare diagnoses
- Sigmoid volvulus: Although the CT scan findings could be consistent with a volvulus, the patient's symptoms and response to treatment make this less likely.
- Intussusception: This is a rare condition in adults, but it could cause intestinal obstruction and constipation. However, the patient's symptoms and CT scan findings do not strongly support this diagnosis.