Fecal impaction is the accumulation of impacted feces in the rectum or sigmoid colon. It primarily affects the elderly and children, and it is caused by chronic or severe constipation, often concurrent with impaired sensation of feces in the rectum. Difficulty relaxing sphincter pressure and generating rectal contractions can cause stool to build up without relief. Patients with neuropsychiatric disorders or spinal cord injuries are more likely to present with fecal impaction. Signs and symptoms include chronic constipation, abdominal pain, diarrhea, tenesmus, vomiting, and hyperkalemia.

Primary risk factors include inadequate fiber and water intake and colonic hypomotility. Adverse medication effects (eg, opioid effects) can also contribute to constipation, which can lead to fecal impactions.

Management includes manual disimpaction, enemas, and polyethylene glycol treatment. If these methods are unsuccessful, mineral oil enemas and colonoscopy for disimpaction can be considered, as can surgical disimpaction. Addressing the underlying predisposing condition is critical to preventing recurrence.