What is the appropriate workup for a 23-year-old male with left lower quadrant (LLQ) pain and a past medical history (PMH) of colitis?

Workup for 23-Year-Old Male with LLQ Pain and History of Colitis

CT abdomen and pelvis with IV contrast is the first-line imaging modality for evaluating a 23-year-old male with left lower quadrant pain and history of colitis. 1

Initial Clinical Assessment

• Key clinical features to assess:

  • Characteristics of pain (onset, duration, severity)
  • Presence of bloody diarrhea, mucus, rectal urgency, or tenesmus
  • Fever
  • Change in bowel habits
  • Weight loss
  • Extra-intestinal manifestations of inflammatory bowel disease

• Laboratory tests:

  • Complete blood count (CBC) with differential
  • C-reactive protein (CRP) - levels >50 mg/L suggest inflammation
  • Erythrocyte sedimentation rate (ESR)
  • Comprehensive metabolic panel
  • Stool studies (including fecal calprotectin, culture, C. difficile testing)

Imaging Approach

First-Line Imaging:

• CT abdomen and pelvis with IV contrast
  • Sensitivity of 98-99% and specificity of 99-100% 1
  • Allows assessment of disease extent, severity, and complications
  • Can identify alternative diagnoses that mimic colitis flare

The American College of Radiology specifically recommends CT with IV contrast as the preferred imaging modality for evaluating left lower quadrant pain 2, 1. This is particularly important in a patient with known colitis to assess for disease activity, complications, and to rule out other potential causes of pain.

Alternative Imaging Options:

• Ultrasound (sensitivity 61-90%, specificity 90-100%)

  • May be used if radiation exposure is a concern
  • Less reliable than CT for bowel assessment

• MRI abdomen and pelvis

  • Consider if CT is contraindicated
  • Particularly useful for differentiating between active inflammation and fibrosis

Disease-Specific Considerations

For Ulcerative Colitis:

• Endoscopic evaluation is crucial for assessing disease activity 3
• Sigmoidoscopy or colonoscopy with biopsies to:
  • Confirm active inflammation
  • Assess disease extent
  • Rule out superimposed infections (CMV, C. difficile)
  • Evaluate for dysplasia in long-standing disease

For Crohn's Disease:

• Additional small bowel imaging may be necessary
• MR enterography to evaluate small bowel involvement
• Fecal calprotectin to assess inflammatory activity

Complications to Consider

• Abscess formation - requires drainage if ≥3-4 cm 1
• Toxic megacolon - surgical emergency
• Strictures - may cause obstructive symptoms
• Perforation - requires urgent surgical consultation
• Fistula formation - may require surgical intervention

Management Algorithm

1. Mild symptoms with known history of colitis:

   • Laboratory tests (CBC, CRP, stool studies)
   • Consider flexible sigmoidoscopy if symptoms suggest flare
   • CT with IV contrast if symptoms are atypical or severe

2. Moderate-severe symptoms:

   • CT abdomen and pelvis with IV contrast
   • Surgical consultation if evidence of perforation, abscess, or toxic megacolon
   • Endoscopic evaluation once acute symptoms improve

3. Atypical presentation or diagnostic uncertainty:

   • CT abdomen and pelvis with IV contrast
   • Consider additional diagnoses such as ischemic colitis 4 or microscopic colitis 5

Common Pitfalls to Avoid

• Relying solely on clinical assessment - clinical suspicion without imaging is only accurate in 40-65% of cases 1
• Delaying imaging in severe cases - can lead to missed complications
• Performing colonoscopy during acute severe flare - increased risk of perforation
• Failing to consider alternative diagnoses - such as diverticulitis, ischemic colitis, or infectious colitis
• Overlooking extraintestinal manifestations - which may contribute to symptoms

By following this evidence-based approach, clinicians can effectively evaluate and manage a young adult with LLQ pain and history of colitis, ensuring appropriate diagnosis and timely intervention when needed.