Fulminant Ulcerative Colitis: Imaging Diagnosis, Emergency Management, and Prognosis

on


#Severe Ulcerative Colitis  #Toxic Megacolon  #Acute Pancolitis  #CT Imaging Findings

Introduction

Fulminant ulcerative colitis (Fulminant UC) represents the most severe and life-threatening manifestation of ulcerative colitis, a chronic inflammatory bowel disease confined to the colon. Although ulcerative colitis typically follows a relapsing–remitting course, fulminant disease is characterized by rapid clinical deterioration, extensive colonic inflammation, systemic toxicity, and a high risk of perforation and mortality.

Despite advances in biologic therapy and intensive care, fulminant UC remains a true medical and surgical emergency, demanding early recognition through clinical features and imaging, immediate multidisciplinary intervention, and decisive escalation to surgery when medical therapy fails.

This column provides a comprehensive, evidence-based review of fulminant ulcerative colitis, integrating pathophysiology, epidemiology, clinical presentation, imaging features, differential diagnosis, diagnostic strategy, treatment, and prognosis, with direct correlation to the provided CT and pathology images.

Epidemiology

Ulcerative colitis affects approximately 120–250 per 100,000 individuals in Western countries, with increasing incidence in Asia and developing regions. Fulminant UC occurs in approximately 5–10% of patients during the disease course.

Key epidemiologic features include:

  • Peak incidence in young adults (15–35 years)

  • Slight male predominance in fulminant cases

  • Higher risk in patients with recent diagnosis, extensive colitis, or poor response to corticosteroids

Importantly, fulminant UC may be the initial presentation, as illustrated in the presented 21-year-old male patient.

Pathophysiology

Fulminant ulcerative colitis represents uncontrolled immune-mediated inflammation of the colonic mucosa with rapid progression to transmural involvement.

Key mechanisms include:

  1. Dysregulated mucosal immunity

    • Excessive activation of Th2-mediated cytokines (IL-5, IL-13)

    • Loss of epithelial barrier integrity

  2. Massive inflammatory mediator release

    • TNF-α, IL-1β, IL-6

    • Nitric oxide–mediated smooth muscle paralysis

  3. Microvascular dysfunction

    • Ischemia and impaired healing

    • Increased risk of necrosis and perforation

  4. Colonic dilation and paralysis

    • Progression to toxic megacolon

    • Loss of haustration and mural tension failure

These mechanisms culminate in severe mucosal ulceration, bleeding, systemic inflammatory response, and mechanical instability of the colon.

Clinical Presentation

Patients with fulminant UC present with rapidly progressive gastrointestinal and systemic symptoms.

Common features:

  • Profuse bloody diarrhea (>10 stools/day)

  • Severe abdominal pain and distension

  • Fever, tachycardia, hypotension

  • Weight loss and dehydration

  • Electrolyte imbalance and anemia

  • Signs of sepsis or shock in advanced cases

The presented patient exhibited progressive bloody diarrhea and weight loss, refractory to intravenous corticosteroids, parenteral nutrition, and blood transfusion—hallmarks of steroid-refractory fulminant disease.

Imaging Features

Figure 1. Scout Image

Description:
The scout radiograph demonstrates marked colonic dilatation, particularly of the transverse colon.

Interpretation:
Colonic diameter exceeding 6 cm strongly suggests toxic megacolon, a life-threatening complication of fulminant UC.

Figure 2. Contrast-Enhanced Coronal CT

Findings:

  • Diffuse pancolitis

  • Intense mucosal hyperenhancement

  • Pronounced submucosal edema (yellow arrows)

  • Loss of haustration (red arrows)

  • Free intraperitoneal air consistent with perforation

Radiologic Significance:
These findings indicate severe transmural inflammation with impending or established perforation, necessitating emergent surgical intervention.

Figure 3. Histopathologic Image

Microscopic Features:

  • Crypt abscesses

  • Dense lymphoplasmacytic infiltration

  • Extensive mucosal ulceration

Pathologic Correlation:
Classic features of active ulcerative colitis, confirming the inflammatory etiology and excluding infectious mimics.

Figure 4. Scout Image (Quiz Image)

Key Observation:
Massive colonic distension with systemic toxicity.

Correct Diagnosis:
Ulcerative colitis (Fulminant type)

Differential Diagnosis

The radiologic and clinical differential diagnosis includes:

  • Infectious colitis (Clostridioides difficile)

  • Ischemic colitis

  • Crohn’s disease

  • Hirschsprung disease (pediatric, chronic)

  • Mechanical large bowel obstruction

  • Intestinal pseudo-obstruction

The continuous colonic involvement, mucosal pattern, and histology favor fulminant UC.

Diagnosis

Diagnosis relies on integration of clinical severity, laboratory markers, imaging, and endoscopic findings.

Diagnostic criteria include:

  • Severe systemic toxicity

  • ≥6 bloody stools/day

  • Elevated CRP and ESR

  • CT findings of pancolitis ± toxic megacolon

  • Exclusion of infection

Endoscopy should be limited to flexible sigmoidoscopy due to perforation risk.

Treatment

Initial Medical Management

  • High-dose intravenous corticosteroids

  • Aggressive fluid and electrolyte replacement

  • Broad-spectrum antibiotics

  • Nutritional support

  • Close ICU monitoring

Rescue Therapy

  • Infliximab or cyclosporine (in selected cases)

Surgical Management

Indications:

  • Steroid-refractory disease

  • Perforation

  • Massive hemorrhage

  • Toxic megacolon

Procedure:
Emergency total abdominal colectomy with end ileostomy, as performed in this patient.

Prognosis

With prompt intervention:

  • Mortality <5% in specialized centers

  • Delayed surgery increases mortality >20%

  • Long-term prognosis improves with definitive colectomy

Early recognition and decisive escalation remain the most critical prognostic factors.

Quiz

Question 1. A patient with ulcerative colitis presents with colonic dilation >6 cm, fever, and tachycardia. The most concerning diagnosis is:

A. Crohn’s disease
B. Ischemic colitis
C. Toxic megacolon
D. IBS

Answer: C. Explanation: Colonic dilation with systemic toxicity defines toxic megacolon.

Question 2. Which CT feature most strongly suggests fulminant UC?

A. Skip lesions
B. Mucosal hyperenhancement with submucosal edema
C. Small bowel involvement
D. Cobblestone appearance

Answer: B. Explanation: Continuous pancolitis with mucosal hyperenhancement is characteristic.

Question 3. The definitive treatment for perforated fulminant UC is:

A. Oral steroids
B. Biologic therapy
C. Endoscopic decompression
D. Total colectomy

Answer: D. Explanation: Surgery is life-saving in perforation.

References

  1. Dinesen LC et al., Lancet, 2010.

  2. Turner D et al., Gastroenterology, 2007.

  3. Truelove SC, Witts LJ, BMJ, 1955.

  4. Harbord M et al., J Crohns Colitis, 2017.

  5. Kornbluth A, Sachar DB, Am J Gastroenterol, 2010.

  6. ECCO Guidelines, J Crohns Colitis, 2023.

  7. Greenstein AJ et al., Ann Surg, 1976.

Comments

Post a Comment