Episode 209: Blast Crisis

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May 1, 2025

Join Sadakat Chowdhury, an emergency medicine physician specializing in ARDS and trauma, as he uncovers the urgent complexities of blast crisis in chronic myeloid leukemia. Discover the critical symptoms stemming from pancytopenia and leukostasis, impacting multiple systems from neurological to cardiopulmonary. Chowdhury discusses key management strategies in emergency care and navigates the ethical dilemmas that arise, emphasizing the balance between aggressive treatment and patient autonomy. A must-listen for insights into this oncologic emergency!

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INSIGHT

Blast Crisis Defined and Urgency

Blast crisis is an oncologic emergency marked by >20% blasts in blood or marrow with extramedullary proliferation.
Untreated, median survival is just 3–6 months, underscoring urgent recognition and management.

INSIGHT

Risk Factors for Blast Crisis

Around 10% of CML patients progress to blast crisis despite treatment.
Risk increases with tyrosine kinase inhibitor resistance, certain chromosomal abnormalities, and very high WBC counts (>100,000).

INSIGHT

Clinical Signs of Blast Crisis

Symptoms derive from pancytopenias causing fatigue, infection risk, and bleeding.
Leukostasis causes neurologic, cardiopulmonary, and other organ dysfunction, leading to rapid clinical deterioration.

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We dive into the recognition and management of blast crisis.

Hosts:
Sadakat Chowdhury, MD
Brian Gilberti, MD

Download 2 Comments Tags: Hematology, Oncology

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.
Rapid deterioration is common — early recognition is critical.

Diagnostic Workup

CBC with differential: assess blast % and cytopenias.
Peripheral smear and manual diff: confirm immature blasts.
CMP: screen for tumor lysis syndrome:
- Elevated potassium, phosphate, uric acid.
- Low calcium.
LDH & uric acid: markers of high cell turnover.
Coagulation studies (PT, PTT): assess for DIC.
Definitive tests (done inpatient): bone marrow biopsy, flow cytometry.

Emergency Department Management

Resuscitation & ABCs: oxygen, IV fluids, vitals monitoring.
Avoid aggressive transfusions:
- Risk of hyperviscosity with PRBCs and platelets.
Initiate broad-spectrum antibiotics early:
- High suspicion for sepsis in functionally neutropenic patients.
Consider antifungals for prolonged febrile neutropenia.
Cytoreduction strategies:
- Hydroxyurea to lower WBCs quickly.
- Tyrosine kinase inhibitors (TKIs).
- High-dose chemotherapy.
Early consultation with hematology/oncology is essential.
Mutation testing may guide targeted therapy.

Prognosis

Without treatment: median survival ~3 months.
With treatment:
- Potential survival >1 year.
- Best outcomes in patients who enter a second chronic phase and undergo allogeneic stem cell transplant.

Ethical & Logistical Considerations

Treatment may involve aggressive interventions with serious side effects.
Important to assess:
- Patient goals of care.
- Capacity for informed consent.
Resource limitations:
- Not all hospitals have oncology services.
- Patients may require transfer over long distances.
Emphasize early, transparent discussions with patients and families.

Top 3 Take-Home Points

Recognize early: Look for cytopenias, leukostasis, and rapid clinical decline.
Resuscitate appropriately: Start antibiotics; be cautious with transfusions.
Call for help: Early hematology/oncology involvement is essential for definitive care.