What are the causes, clinical presentation, imaging findings, and management of stercoral colitis in an elderly, immobile patient with chronic constipation?

Stercoral Colitis: A Comprehensive Breakdown

Definition and Pathophysiology

Stercoral colitis is a rare but life-threatening inflammatory condition of the colon caused by impacted fecal material that leads to pressure necrosis, mucosal ulceration, and transmural inflammation of the bowel wall. 1, 2 The condition occurs when chronic fecal impaction creates a fecaloma that exerts sustained pressure on the colonic mucosa, resulting in ischemia, inflammation, and potentially perforation. 3

Causes and Risk Factors

Primary Risk Populations

• Elderly, bedbound, or immobile patients with chronic constipation represent the highest-risk group. 1, 3
• Nursing home residents are particularly vulnerable due to limited mobility and polypharmacy. 4
• Patients with mental impairment or intellectual disability who cannot communicate bowel symptoms effectively. 4

Contributing Factors

• Chronic opioid use, which significantly slows colonic motility. 4
• Recent orthopedic surgery (particularly hip fractures) requiring prolonged immobilization. 3
• Neurogenic bowel disorders affecting colonic function. 5
• Medications that slow gastrointestinal transit, including anticholinergics and calcium channel blockers. 5

Important caveat: While stercoral colitis predominantly affects elderly patients, it can occur in younger individuals with significant comorbidities predisposing to fecal impaction. 1, 4

Clinical Presentation

Typical Symptoms

• Acute abdominal pain and distension are the most common presenting complaints. 1, 3
• Absence of bowel movements or flatus for several days. 3
• Nausea and vomiting. 4

Critical Warning Signs

• The clinical presentation is often nonspecific and varied, making diagnosis challenging. 1
• Patients may present with sepsis or septic shock, even without perforation. 4
• Syncope and confusion can be initial manifestations in severe cases. 4
• Physical examination typically reveals abdominal distension with tenderness, though peritoneal signs may be absent initially. 3

Major pitfall: The absence of typical constipation symptoms does not exclude stercoral colitis, as patients with cognitive impairment may not report bowel habit changes. 4

Imaging Findings

CT Scan: The Diagnostic Gold Standard

CT of the abdomen and pelvis is crucial for diagnosis and reveals the following key findings: 1, 3

• Fecaloma: Large, impacted fecal mass in the colon (most commonly rectosigmoid). 3
• Colonic dilatation: Massive distension of the affected colonic segment. 3
• Mural thickening: Focal thickening of the colonic wall at the site of impaction. 3
• Pericolic fat stranding: Inflammatory changes in the pericolonic fat. 3
• Free fluid: Minimal to moderate free fluid in the abdomen and pelvis. 3
• Absence of pneumoperitoneum in non-perforated cases. 4

Plain Radiography

• Abdominal X-rays demonstrate bowel distention and abundant fecal material in the colorectal regions. 3
• Plain films are insufficient for definitive diagnosis but may raise initial suspicion. 3

Differential Diagnosis

Stercoral colitis mimics several other colonic pathologies, requiring careful differentiation: 2

• Ischemic colitis: Distinguished by cardiovascular risk factors and sharp demarcation between viable and ischemic mucosa on endoscopy. 6
• Diverticulitis: May coexist but typically shows localized inflammation without massive fecal impaction. 7
• Inflammatory bowel disease: Lacks the characteristic fecaloma and has different endoscopic patterns. 6, 7
• Colorectal cancer: Must be excluded in elderly patients with new bowel symptoms. 7

Management Approach

Initial Emergency Department Management

All patients with stercoral colitis should be admitted for intensive monitoring. 8

Immediate Interventions

• Aggressive IV fluid resuscitation to correct dehydration and optimize colonic perfusion. 6
• Electrolyte replacement, particularly potassium supplementation of at least 60 mmol/day. 6
• Stool testing for Clostridioides difficile is mandatory in all cases, as this pathogen significantly increases morbidity and mortality. 6
• Initiate multimodal bowel regimen immediately upon diagnosis. 8

Monitoring Parameters

• Vital signs checked four times daily to detect early deterioration. 6
• Complete blood count, CRP, serum electrolytes, and serum albumin every 24-48 hours. 6
• Daily plain abdominal radiographs if colonic dilatation is suspected, as transverse colon diameter >5.5 cm indicates severe disease and impending perforation. 6

Conservative Management (Non-Complicated Cases)

Most cases of stercoral colitis can be managed conservatively without surgery. 1, 3

Bowel Decompression

• Manual disimpaction through digital fragmentation and extraction of stool when rectal impaction is present. 5
• Enemas and suppositories are first-line therapy when digital rectal examination identifies a full rectum or fecal impaction. 5
• Isotonic saline enemas are preferable in elderly adults due to lower risk of electrolyte disturbances. 5

Laxative Therapy

• Osmotic laxatives (PEG 17 g/day, lactulose, or magnesium salts) offer efficacious and tolerable solutions for elderly patients. 5
• Stimulant laxatives (senna, bisacodyl, sodium picosulfate) can be used but may cause cramping. 5
• Avoid bulk laxatives (psyllium) in non-ambulatory patients with low fluid intake due to increased risk of mechanical obstruction. 5
• Avoid liquid paraffin in bed-bound patients due to aspiration risk. 5

Critical contraindications for enemas: Neutropenia, thrombocytopenia, paralytic ileus, intestinal obstruction, recent colorectal surgery, severe colitis, toxic megacolon, or recent pelvic radiotherapy. 5

Antibiotic Therapy

• Parenteral antibiotics should be initiated if there are signs of sepsis, transmural inflammation, or concern for perforation. 8
• Add oral vancomycin 125 mg four times daily for 10 days if C. difficile is detected. 6

Thromboprophylaxis

• Administer subcutaneous low-molecular-weight heparin for thromboembolism prophylaxis, as the risk is substantially elevated during stercoral colitis episodes. 6

Medication Adjustments

• Stop NSAIDs immediately, as they can precipitate or worsen ischemic changes. 6
• Do not abruptly discontinue essential cardiac medications without cardiology consultation, as hemodynamic consequences may worsen colonic perfusion. 6

Surgical Management (Complicated Cases)

Immediate surgical consultation is required for: 8, 4

• Bowel perforation (pneumoperitoneum on imaging)
• Peritonitis on physical examination
• Septic shock despite resuscitation
• Transmural necrosis
• Failed conservative management with clinical deterioration

Surgical Approach

• Extended colectomy with Hartmann's procedure (resection with end-colostomy) is the standard operation. 4
• Resection of the ischemic segment with exteriorization rather than primary anastomosis is mandatory, as anastomosis carries unacceptable risk in the setting of ischemia, sepsis, and malnutrition. 6
• Involve a colorectal surgeon from the time of admission for patients with severe presentations to facilitate rapid surgical intervention if needed. 6

Nutritional Support

• Provide nutritional support if the patient is malnourished, preferably via the enteral route once bowel function returns, as it is associated with fewer complications than parenteral nutrition. 6

Prognosis and Complications

Mortality Risk

• Stercoral colitis carries high morbidity and mortality rates, particularly when complicated by perforation or sepsis. 1, 2
• Non-perforated stercoral colitis patients with septic shock have higher mortality than their perforated counterparts, highlighting the severity of transmural necrosis even without frank perforation. 4

Potential Complications

• Stercoral ulceration with bleeding. 4
• Colonic perforation with peritonitis. 1, 3
• Ischemic colitis and transmural necrosis. 4
• Sepsis and septic shock. 4
• Death if not promptly recognized and treated. 4

Prevention Strategies in High-Risk Patients

For Elderly, Immobile Patients

• Ensure access to toilets and optimize toileting schedules (attempt defecation twice daily, 30 minutes after meals, strain no more than 5 minutes). 5
• Encourage mobility within patient limits, even bed-to-chair transfers. 5
• Provide dietetic support and manage decreased food intake. 5
• Anticipatory management of constipation when opioids are prescribed with concomitant laxative therapy. 5

Laxative Prophylaxis

• All patients receiving opioid analgesics should be prescribed a concomitant laxative unless contraindicated by pre-existing diarrhea. 5
• Osmotic or stimulant laxatives are generally preferred for opioid-induced constipation. 5
• Regular monitoring of chronic kidney/heart failure when diuretics or cardiac glycosides are prescribed due to risk of dehydration and electrolyte imbalances. 5

Common Pitfalls to Avoid

• Do not delay treatment while awaiting stool culture results in severe presentations. 6
• Do not confuse stercoral colitis with inflammatory bowel disease in older adults—the presence of massive fecal impaction and sharp demarcation on imaging strongly indicates stercoral colitis. 6
• Maintain high clinical suspicion in elderly patients with nonspecific abdominal complaints, as typical constipation symptoms may be absent. 1, 4
• Do not assume conservative management will suffice—early surgical consultation is essential for all but the mildest cases. 8
• Recognize that sepsis can occur without perforation and requires aggressive management. 4