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
- Primary survey and vitals; IV access and monitors.
- Focused history/physical; identify red flags and likely etiologies.
- Order system-appropriate labs and imaging (see Investigations).
- Initiate guideline-based empiric therapy (see Pharmacology).
- Reassess response; arrange consultation and definitive management.
Clinical Synopsis & Reasoning
For Colorectal Cancer Mismatch Repair Testing Msi, 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., Common Patterns) 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.
Epidemiology / Risk Factors
- Risk factors vary by condition and patient profile
Investigations
| Test | Role / Rationale | Typical Findings | Notes |
|---|---|---|---|
| CBC | Baseline hematology | Abnormal counts | |
| BMP | Electrolytes/renal | Derangements |
Common Patterns
| IHC loss | Next step |
|---|---|
| MLH1 PMS2 | Test for BRAF or MLH1 methylation |
| MSH2 MSH6 | Genetic counseling for Lynch |
| Isolated MSH6 or PMS2 | Consider germline testing |
Pharmacology
| Medication | Mechanism | Onset | Role in Therapy | Limitations |
|---|---|---|---|---|
| Dexamethasone | Glucocorticoid | Hours | Peritumoral edema, antiemetic adjunct | Hyperglycemia |
| Ondansetron | 5-HT3 antagonism | Minutes | Antiemesis | QT |
| Zoledronic acid/Denosumab (if bony metastases) | Osteoclast inhibition | Days | Prevent SREs | Hypocalcemia; ONJ |
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.
Notes
Use validated assays and controls. Include statement about possible implications for other cancers in families.