Show Notes

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.

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.

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.

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.

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.

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.

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.

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.

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.

Episode 209: Blast Crisis