Fecal impaction
Background
- Typically a complication of chronic constipation that results in the accumulation of hardened/inspissated fecal matter in the colon or rectum that cannot be spontaneously evacuated
- Incidence greatly increases with age and polypharmacy; common in the inpatient or institutionalized setting
Risk Factors
- Elderly and young age
- Chronic constipation
- Lifestyle factors (immobility/bedbound, low fiber diet, dehydration)
- Medications that impair GI motility (anticholinergics, antipsychotics, opioids)
- Metabolic disorders (hypothyroidism, Diabetes
- Anatomic abnormalities (malignancy, anorectal disease, Hirschsprung's disease)
- Neurologic conditions (dementia, spinal cord injury, cerebral palsy)
Clinical Features
History
- Abdominal pain, bloating, distention, or early satiety
- Nausea and vomiting
- Overflow stool incontinence as diarrhea
- Obstipation
- Agitation/confusion (elderly patients with neuropsychiatric conditions)
- Tachycardia may be present due to pain or dehydration
- Urinary incontinence
Physical exam
- Abdominal distention and/or tenderness
- Palpable firm stool balls or copious amounts of stool found on digital rectal exam
- Note that for proximal impactions (proximal rectum or sigmoid colon), DRE may not be diagnostic
Differential Diagnosis
Constipation
- Behavioral-related
- Lack of exercise
- Diet-related
- Fecal impaction
- Ileus from surgical abdomen
- Bowel obstruction
- Small bowel obstruction
- Large bowel obstruction
- Malignant bowel obstruction
- Specific causes: tumor, stricture, hernia, adhesion, volvulus
- Painful anorectal disorders (e.g. anal fissure, hemorrhoids)
- Medical causes
- Hypothyroidism
- Electrolytes
- Hypokalemia
- Medication-related
- Opiods, antipsychotics, anticholinergics, antacid, antihistamines
- Constipation (peds)
Evaluation
Workup
- Digital rectal exam
- Abdominal panel
- CBC
- Chemistry (hypokalemia or hypercalcemia)
- LFTs + lipase
- Consider coagulation studies (PT, PTT, INR), as a marker of liver function
- Consider TSH if concern for hypothyroid related constipation
- Consider lactate if concern for stercoral colitis
- CT if abdominal tenderness, elderly, or severe presentation
- Constipation should not cause abdominal tenderness on exam
- CT may show large stool burden in colon/rectum
- Stercoral colitis is CT finding caused by impacted fecal material causing pressure edema and ischemia on the bowel wall. Left untreated, the condition can lead to wall ischemia, ulceration, and perforation.[1]
- Findings include colonic wall thickening, pericolonic fat stranding, and extraluminal bubbles of gas or abscess (signs of perforation); all of which are not found in uncomplicated fecal impaction.
Diagnosis
- Diagnosis is frequently clinical
- In patients with concerning symptoms/risk factors, CT can confirm diagnosis and rule out more emergent conditions
Management
- Surgery if there are signs of perforation, peritonitis, or stercoral colitis
- In severe cases refractory to mainstay treatments, manual disimpaction under anesthesia in OR may be requried[2]
- Distal impactions - manual disimpaction and/or rectal suppositories or enemas (Fleet, mineral oil, warm water, docusate)
- Administration of small-volume enemas over a longer time may be more beneficial and comfortable for patient
- In small studies, Fleet (sodium phosphate) enemas led to to increased rate of electrolyte derangements in the elderly[3]
- Proximal impactions typically respond better to oral laxatives
- After initial disimpaction, address risk factors (especially medications) and initiate a maintenance bowel regimen
Disposition
- Consider admission for patients with stercoral colitis for aggressive bowel regimen and washout
- First-time fecal impaction may prompt colonoscopy or flexible sigmoidoscopy to assess for anatomic causes[4]
See Also
References
- ↑ Ünal E, Onur MR, Balcı S, Görmez A, Akpınar E, Böge M. Stercoral colitis: diagnostic value of CT findings. Diagn Interv Radiol. 2017;23(1):5-9.
- ↑ Setya A, Mathew G, Cagir B. Fecal Impaction. [Updated 2023 Jul 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.
- ↑ Ori Y, Rozen-Zvi B, Chagnac A, Herman M, Zingerman B, Atar E, Gafter U, Korzets A. Fatalities and severe metabolic disorders associated with the use of sodium phosphate enemas: a single center's experience. Arch Intern Med. 2012 Feb 13;172(3):263-5. doi: 10.1001/archinternmed.2011.694. PMID: 22332159.
- ↑ Obokhare I. Fecal impaction: a cause for concern? Clin Colon Rectal Surg. 2012 Mar;25(1):53-8. doi: 10.1055/s-0032-1301760. PMID: 23449376; PMCID: PMC3348734.