EM@3AM: Stercoral Colitis

Answer: Stercoral colitis complicated by bowel perforation

Overview:

• Stercoral colitis (SC) is a rare, potentially life-threatening sequela of fecal impaction leading to increased intraluminal pressure, necrosis, ulceration, and perforation of the colon. ^2-7
• Early recognition and high clinical suspicion required given variable clinical presentations and high mortality without treatment.^{2, 3}
  • Mortality rates up to 17-60% with perforation.^{3, 6-10}

Epidemiology:

• SC can present in any age group, from children to elderly.^{3, 9, 11, 12}
  • The average age tends to be greater than 60 years old.
• The true prevalence and incidence of stercoral colitis are poorly described due to under-reporting and understudying, especially in cases with absence of complications.^{2, 3, 11, 13}
  • Most of the available literature is in the form of case studies.
  • There is evidence that the incidence of SC is increasing as the average life expectancy, the prevalence of comorbidities, and opioid use have all increased, and diagnostic imaging is being ordered more frequently
• Commonly defined risk factors in the literature:^{2-6, 8, 9, 11, 13, 14}
  • Chronic constipation leading to fecal impaction is the highest risk factor for SC.
    • Up to 1/3 of adults over 60 suffer from chronic constipation.
  • Limitations in mobility
  • Nursing home or care home residence
  • Neurocognitive impairment, such as dementia
  • Opioid use
  • Psychiatric conditions
  • Comorbidities that can pre-dispose to constipation such as hypothyroidism or renal failure

Pathophysiology:^{2-4, 7, 13, 14}

• Longstanding constipation leads to the development of a fecaloma, which progresses to fecal impaction.
• Fecal impaction causes increased intraluminal pressure in the colon.
• Increased intraluminal pressure leads to colonic distension and dilation.
• Colonic distension leads to vascular compression within the bowel wall, leading to ischemic necrosis, ulceration, and ultimately, perforation of the colonic wall.
• The most common anatomical location for SC is the sigmoid colon, the antimesenteric border of the rectosigmoid junction, and the anterior rectum.^{6, 13, 14}
  • 77% of SC ulcers are found in the sigmoid colon and rectum.³
  • These regions exhibit decreased perfusion in watershed areas, smaller luminal diameters, and lower stool water content.

Clinical Presentation:

• SC’s presentation is highly variable and nonspecific. A high degree of clinical suspicion needs to be maintained to recognize SC as a possibility.^{2, 3, 7, 8}
  • There is no pathognomonic constellation of symptoms allowing for a clinical diagnosis of SC.
• One recent study showed the most common patient complaints to be abdominal pain and distension, constipation, and nausea with vomiting.^{2, 8, 10}
  • The textbook presentation would be an elderly patient with chronic constipation, multiple comorbidities, and decreased mobility presenting with vague abdominal pain with nausea, vomiting, and abdominal distension.
  • Abdominal pain may be absent in up to 60%.^{2, 8-10, 14}
• The clinical symptoms range from vague abdominal pain to florid septic shock and peritonitis secondary to bowel perforation.^2,3
  • Colicky abdominal pain can indicate ischemic colitis.
  • Perforation usually will have sudden and severe onset of pain and peritoneal symptoms.
  • Symptoms can mimic diverticulitis.
• Clinical exam:^{2, 3, 9}
  • Abdominal distension and tenderness
  • Nausea and vomiting
  • Stool present in the rectal vault
  • Peritonitis may be accompanied by hemodynamic instability in the case of sepsis.
  • May still be passing small amounts of stool and flatus.

Evaluation:

• A good history and a high index of clinical suspicion is paramount, especially in high-risk patient populations ⁴
• CT of the abdomen and pelvis with contrast is the best choice for diagnosis.^{2-9, 11, 13, 14}
  • There are no “official” diagnostic criteria on imaging for stercoral colitis
  • Studies have suggested that the presence of certain features suggest SC:
    • Fecaloma
    • Colonic dilation >6cm
    • Thickening of the colon wall >3mm
    • Peri-colonic fat stranding
    • Evidence of colon perforation, including extraluminal gas, bowel wall gas, and abscesses
•  Plain films can suggest findings of impaction, constipation, or reveal free air indicating possible perforation, but cannot formally diagnose SC.^2,3
• Laboratory testing is nonspecific but can show leukocytosis, elevated acute phase reactants, lactic acidosis (concerning for bowel ischemia).^{2-4, 6}
  • If there is a concern for perforation or sepsis, surgical consultation, blood cultures, empiric antibiotics, and fluids are recommended.

Treatment:

• The primary goal is to decrease the intraluminal pressure by removal of the fecaloma.^2,3
• Nonoperative medical management is appropriate for most cases without peritonitis or evidence of perforation on imaging. Treatments include: ^{2-4, 6, 8, 9, 13, 14}
  • Fecal disimpaction either manually or with endoscopic guidance.
  • Enemas (some studies show this may be associated with perforation risk).
    • CT findings of perforation are an absolute contraindication to enema use.
  • Multimodal pain management avoiding opioid use.
  • Monitor for fever, perform serial exams, monitor for leukocytosis and lactic acidosis development as signs of complications, and keep a low threshold for empiric antibiotic coverage for gram-negative and anaerobic organisms and blood cultures. For empiric antibiotic coverage, consider: ¹⁷
    • Piperacillin/tazobactam 4.5g IV QID (pedi dose 100 mg/kg)
    • Metronidazole 500mg IV TID (pedi dose 10mg/kg) PLUS Cefepime 2g IV TID (pedi dose 50mg/kg)
    • Meropenem 1g IV TID (pedi dose 20mg/kg)
  • Oral bowel regimen for constipation management:
    • Increase dietary fiber and fluid intake.
    • Daily stool softener use.
    • If using laxatives, osmotic and stimulant laxatives are first line (polyethylene glycol and senna).
    • Avoid medications that induce constipation.
•  Operative management is necessary for signs of peritonitis, evidence of perforation, extensive bowel involvement >40cm, or after failed medical management.^{2-4, 6, 8, 9, 12, 13, 14}
  • Operative intervention typically consists of emergency laparotomy with bowel resection, colostomy formation, and Hartmann pouch creation.
  • The two highest predictors of increased mortality in the literature include a large area of colonic involvement >40cm and perforation (32-60% mortality rate).
  • If sepsis or septic shock is present, aggressive fluid resuscitation and empiric antibiotics covering intra-abdominal flora should be administered.

Disposition:

• Disposition is dependent on the severity of the presentation, but in most situations, admission is necessary.
• Admission allows for close monitoring, given the risks of perforation, ischemic bowel, and ulceration, as well as appropriate management of the condition and patient symptoms.^2-4
• Any patient with evidence of complications or septic shock may need surgical management or a higher level of care.^{4, 8}

Pearls:

• Stercoral colitis is a rare complication of constipation with a high mortality rate, requiring high suspicion for diagnosis.
• Diagnose with imaging; early CT abdomen and pelvis with contrast recommended.
• Admission is recommended for these patients for monitoring, given the high risk of progression to bowel necrosis, ulceration, perforation, and sepsis.
• Low threshold for antibiotics and escalation of care with surgery consultation.