What are the diagnostic criteria and treatment options for ulcerative colitis?

Diagnostic Criteria and Treatment Options for Ulcerative Colitis

The diagnosis of ulcerative colitis requires a combination of clinical history, laboratory tests, endoscopy with histopathology, and exclusion of infectious causes, as there is no single gold standard diagnostic test. 1

Diagnostic Criteria

Clinical Assessment

• A comprehensive medical history should include detailed questioning about onset of symptoms, rectal bleeding, stool consistency and frequency, urgency, tenesmus, abdominal pain, incontinence, and nocturnal diarrhea 1
• Recent travel, possible infectious contacts, medication use (including antibiotics and NSAIDs), smoking status, sexual behavior, family history of IBD or colorectal cancer, and previous appendectomy should be documented 1
• Physical examination findings depend on disease severity - patients with mild to moderate disease may have unremarkable examinations except for blood on rectal examination, while those with severe disease may present with fever, tachycardia, weight loss, abdominal tenderness, distension, and reduced bowel sounds 1

Initial Laboratory Investigations

• Full blood count, electrolytes, liver and renal function, iron studies, vitamin D level, C-reactive protein (CRP), and fecal calprotectin should be obtained 1
• Immunization status should be assessed 1
• Stool specimens must be collected to exclude infectious causes, particularly Clostridium difficile 1
• In patients with severe clinical activity, elevated CRP is generally associated with elevated ESR, anemia, and hypoalbuminemia, which can serve as predictive biomarkers for colectomy risk in acute severe colitis 1

Endoscopic Evaluation

• Ileocolonoscopy with biopsy is essential for definitive diagnosis 1, 2
• The pathognomonic endoscopic finding is continuous colonic inflammation characterized by erythema, loss of normal vascular pattern, granularity, erosions, friability, bleeding, and ulcerations 2
• Inflammation typically begins at the anal verge and extends proximally in a continuous, confluent, and concentric fashion with clear demarcation between inflamed and normal areas 1
• In patients with acute severe colitis, flexible sigmoidoscopy rather than full colonoscopy is recommended to confirm diagnosis and exclude infection 1
• The Mayo scoring system is commonly used to assess endoscopic severity, with scores ranging from 0 (normal) to 3 (spontaneous bleeding) 1, 2

Histopathological Assessment

• For reliable diagnosis, a minimum of two biopsies from at least five sites around the colon (including the rectum) and the ileum should be obtained 1
• Basal plasmacytosis is the earliest diagnostic feature with the highest predictive value for UC diagnosis 1
• Established disease shows widespread crypt architectural distortion, mucosal atrophy, diffuse transmucosal inflammatory infiltrate with basal plasmacytosis, and active inflammation causing cryptitis and crypt abscesses 1
• A decreasing gradient of inflammation from distal to proximal favors UC diagnosis 1
• Histological healing is distinct from endoscopic mucosal healing and persistent histological inflammation may be associated with adverse outcomes 1

Imaging Studies

• Abdominal CT scanning is the preferred initial radiographic imaging in UC patients with acute abdominal symptoms 2
• The hallmark CT finding is mural thickening with a mean wall thickness of 8 mm (compared to normal 2-3 mm) 2
• Non-invasive imaging like abdominal X-ray, CT, or ultrasound can help define disease extent and complications 1

Treatment Options

Mild to Moderate Disease

• For proctitis (distal disease), topical 5-aminosalicylic acid (5-ASA) drugs are first-line agents 2, 3
• For more extensive disease, a combination of oral and topical 5-ASA drugs is recommended to induce remission 2, 3

Moderate to Severe Disease

• Oral corticosteroids are used for induction of remission as a bridge to maintenance therapy 3
• Maintenance therapy options include:
  • Biologic monoclonal antibodies against:
    • Tumor necrosis factor (e.g., infliximab) 4, 3
    • α4β7 integrins (vedolizumab) 3
    • Interleukin 12 and IL-23 (ustekinumab) 3
  • Oral small molecules that inhibit janus kinase (e.g., tofacitinib) or modulate sphingosine-1-phosphate (ozanimod) 3

Severe Disease

• Patients with severe UC require hospitalization 2
• Treatment options include:
  • Intravenous corticosteroids 2
  • If refractory, calcineurin inhibitors (cyclosporine, tacrolimus) or infliximab 2
  • Emergency surgery is indicated for refractory toxic megacolon, colonic perforation, or severe colorectal bleeding 2

Monitoring Response to Treatment

• Response should be determined by a combination of clinical parameters, endoscopy, and laboratory markers such as CRP and fecal calprotectin 1
• In patients who clinically respond to medical therapy, mucosal healing should be assessed endoscopically or by fecal calprotectin approximately 3-6 months after treatment initiation 1
• Mucosal healing is associated with reduced risk of colectomy and lower inflammation at 5 years 1

Common Pitfalls and Caveats

• There is no gold standard for UC diagnosis; it is established through a combination of clinical, laboratory, imaging, and endoscopic parameters including histopathology 1
• Infectious causes must be excluded before confirming diagnosis 1
• Microbial testing is recommended in patients with colitis relapse, particularly for C. difficile and Cytomegalovirus infection 1
• Disease extent can change after diagnosis - up to half of patients with proctitis or proctosigmoiditis will develop more extensive disease over time 1
• Repeat endoscopy with histopathological review may be necessary if diagnostic doubt remains 1
• Patients with extensive colitis have higher risk of colectomy and colorectal cancer compared to those with limited disease 1