USMLE Prep - Medical Reference Library

Colorectal Cancer — Emergency Obstruction or Perforation

System: General Surgery • Reviewed: Aug 31, 2025 • Step 1Step 2Step 3

Synopsis:

Emergency CRC presents with obstruction or perforation. Prioritize resuscitation, source control, and oncologic principles. Consider stenting as a bridge to surgery in left‑sided obstruction; perform resection with diversion when unstable or contaminated.

Key Points

  • Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
  • Use system-specific risk tools to guide testing and disposition.
  • Order high-yield tests first; escalate imaging when indicated.
  • Start evidence-based initial therapy and reassess frequently.

Algorithm

  1. Primary survey and vitals; IV access and monitors.
  2. Focused history/physical; identify red flags and likely etiologies.
  3. Order system-appropriate labs and imaging (see Investigations).
  4. Initiate guideline-based empiric therapy (see Pharmacology).
  5. Reassess response; arrange consultation and definitive management.

Clinical Synopsis & Reasoning

For Colorectal Cancer Emergency Obstruction Or Perforation, frame the differential by acuity and pathophysiology, then align diagnostics to the leading hypotheses. Prioritize stabilization while obtaining high‑yield studies such as CBC (Baseline hematology), BMP (Electrolytes/renal). Incorporate bedside imaging and targeted labs to define severity and identify complications; synthesize results with clinical trajectory to refine the working diagnosis and disposition needs.


Treatment Strategy & Disposition

Initiate disease‑directed therapy alongside supportive care, titrating to objective response. Pharmacologic options commonly include Analgesia/Antipyretics. Use validated frameworks (e.g., Left‑Sided Obstruction Options) to guide escalation and site of care. Address precipitating factors, de‑escalate empiric therapies with data, and arrange follow‑up for monitoring and risk‑factor modification; admit patients with instability, high risk of deterioration, or needs for close monitoring.


Management Notes

Discuss goals (curative vs palliative). Ensure anticoagulation/VTE prophylaxis and ERAS elements even in urgent settings when possible.


Epidemiology / Risk Factors

  • Risk factors vary by condition and patient profile

Investigations

TestRole / RationaleTypical FindingsNotes
CBCBaseline hematologyAbnormal counts
BMPElectrolytes/renalDerangements

Left‑Sided Obstruction Options

OptionPros/Cons
SEMS bridgeHigher primary anastomosis rate; avoid emergency surgery; risk of perforation
Hartmann’s procedureStable diversion; reversal uncertain
Resection + primary anastomosis ± diversionFaster recovery if feasible; leak risk
Loop colostomyPalliative decompression; staged
Right‑sided obstructionRight hemicolectomy ± ileostomy

Pharmacology

MedicationMechanismOnsetRole in TherapyLimitations
Piperacillin-tazobactamBroad intra-abdominal coverageHoursPre-op/sepsis controlAKI; ED use; pregnancy/lactation considerations

Prognosis / Complications

  • Prognosis depends on severity, comorbidities, and timeliness of care

Patient Education / Counseling

  • Explain red flags and when to seek emergent care.
  • Reinforce medication adherence and follow-up plan.

References

  1. ESMO/ASCRS Emergency CRC — Link