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 could also be consistent with an ileus caused by constipation. The patient's recent dehydration and dietary choices may have contributed to this condition.
- Opioid-induced constipation: The patient's use of opioid pain medication could be contributing to their constipation, as opioids are known to cause constipation as a side effect.
- Dehydration-induced constipation: The patient's admission of poor hydration in the days leading up to their constipation suggests that dehydration may have played a role in their condition.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Intestinal obstruction: Although the CT scan suggests that the narrowing in the sigmoid colon may be due to peristalsis, an underlying stricture or mass could not be excluded. Intestinal obstruction is a potentially life-threatening condition that requires prompt diagnosis and treatment.
- Colorectal cancer: Although the patient has no family history of colorectal cancer, it is still important to consider this possibility, especially given the patient's age and symptoms.
- Volvulus: A volvulus is a twisting of the intestine that can cause obstruction and ischemia. Although the CT scan does not suggest this diagnosis, it is still important to consider it as a possible cause of the patient's symptoms.
- Rare diagnoses
- Hirschsprung's disease: This is a rare condition characterized by the absence of ganglion cells in the distal colon, leading to severe constipation. Although the patient's age makes this diagnosis unlikely, it is still possible.
- Chronic intestinal pseudo-obstruction: This is a rare condition characterized by recurrent episodes of intestinal obstruction without any mechanical cause. The patient's symptoms and CT scan findings could be consistent with this diagnosis, but it is relatively rare and would require further evaluation to confirm.