II. Definitions

  1. Blast Crisis
    1. Chronic Myelogenous Leukemia late stage progression to >20% blasts in blood or marrow
    2. Results in very high White Blood Cell Counts, Anemia, infection risk, Leukostasis, Tumor Lysis Syndrome

III. Pathophysiology

  1. Late complication of Chronic Myelogenous Leukemia (CML)
  2. Rapid increase in immature White Blood Cells (Lymphoblasts) in the blood and Bone Marrow
    1. Lymphoblasts increase in the Bone Marrow at the expense of other cell lines
    2. White Blood Cells increase causing Leukostasis in the microvasculature
      1. Results in end organ decreased perfusion

IV. Findings

  1. Leukostasis
    1. Respiratory findings (e.g. Dyspnea)
    2. Neurologic findings (e.g. Headaches, confusion)
  2. Bone Marrow infiltration related findings
    1. Gingival Bleeding, easy Bruising or Petechiae
    2. Fatigue
    3. Night Sweats
    4. Bone pain

V. Labs

  1. Complete Blood Count with differential
    1. Lymphoblasts represent >20% of Lymphocytes in Blast Crisis
    2. Lymphoblasts are typically absent from blood
    3. Anemia
    4. Thrombocytopenia
  2. Peripheral Smear
    1. Lymphoblasts prominent with associated Anemia and Thrombocytopenia
  3. Bone Marrow Biopsy
    1. Lymphoblasts represent >20% of Lymphocytes in Blast Crisis
    2. Lymphoblasts are typically 5% of Bone MarrowLymphocytes
  4. Other lab findings related to high blood cell turnover
    1. Serum Uric Acid increased
    2. Lactate Dehydrogenase (LDH) increased

VI. Differential Diagnosis

  1. Chronic Myelogenous Leukemia (CML, with Blast Crisis)
  2. Acute Myelogenous Leukemia (AML, new onset)
  3. Acute Promyelocytic Leukemia (APML)
    1. Associated with Disseminated Intravascular Coagulation (DIC)
    2. Lab findings include increased INR/PTT, D-Dimer and decreased Fibrinogen and Platelet Count

VII. Management

  1. Emergent hematology oncology Consultation
  2. Acute complication management (see below)
    1. Leukostasis
    2. Acute infections
      1. Infection is the most common cause of death in Blast Crisis
    3. Hemorrhage Management
      1. Bleeding complications are the second most common cause of death in Blast Crisis
  3. Consider All-Trans-Retinoic Acid (ATRA) if Acute Promyelocytic Leukemia (APML) is suspected
    1. Promotes transition of Promyelocytes to differentiate into Neutrophils
    2. Reduces Disseminated Intravascular Coagulation (DIC) severity

VIII. Complications

  1. Anemia
    1. Avoid Blood Transfusion if possible (may worsen Blast Crisis)
    2. pRBC Transfuse for hemodynamic instability or uncontrolled Hemorrhage
  2. Thrombocytopenia
    1. Spontaneous Intracranial Hemorrhage risk when Platelet Count <20,000
    2. Platelet Transfusion for Platelet Count <20,000 (<50,000 if current bleeding)
  3. Increased infection risk
    1. Functional Neutropenia or Immunocompromised state
    2. Treat focal infections with broad spectrum Antibiotics
  4. Leukostasis (Hyperviscosity Syndrome)
    1. See Leukostasis for management
    2. CNS and cardiac hypoperfusion from sludging of white cells (>50,000/ul)
    3. Presents with Altered Mental Status, CVA, CHF or Pulmonary Edema
  5. Tumor Lysis Syndrome
    1. See Tumor Lysis Syndrome for management
    2. Presents with fever, Fatigue, weakness, Nausea, Vomiting
    3. Rapid cell death and turnover resulting Electrolyte abnormalities
      1. Hyperkalemia
      2. Hyperphosphatemia
      3. Hyperuricemia
      4. Hypocalcemia
      5. Acute Kidney Injury
      6. Arrhythmia
      7. Seizure

IX. References

  1. Bierowski and Nyalakonda (2025) Crit Dec Emerg Med 39(6): 4-21
  2. Dubbs and Swaminathan in Swadron (2021) Crit Dec Emerg Med 21(12): 18-20

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