Episode 209: Blast Crisis

Show Notes

Topic Overview

• Blast crisis is an oncologic emergency, most commonly seen in chronic myeloid leukemia (CML).
• Defined by:
  • >20% blasts in peripheral blood or bone marrow.
  • May include extramedullary blast proliferation.
• Without treatment, median survival is only 3–6 months.

Pathophysiology & Associated Conditions

• Usually occurs in CML, but also in:
  • Myeloproliferative neoplasms (MPNs)
  • Myelodysplastic syndromes (MDS)
• Transition from chronic to blast phase often reflects disease progression or treatment resistance.

Risk Factors

• 10% of CML patients progress to blast crisis.
• Risk increased in:
  • Patients refractory to tyrosine kinase inhibitors (e.g., imatinib).
  • Those with Philadelphia chromosome abnormalities.
  • WBC >100,000, which increases risk for leukostasis.

Clinical Presentation

• Symptoms often stem from pancytopenia and leukostasis:
  • Anemia: fatigue, malaise.
  • Functional neutropenia: high WBC count, but increased infection/sepsis risk.
  • Thrombocytopenia: bleeding, bruising.
• Leukostasis/hyperviscosity effects by system:
  • Neurologic: confusion, visual changes, stroke-like symptoms.
  • Cardiopulmonary: ARDS, myocardial injury.
  • Others: priapism, limb ischemia, bowel infarction.