II. Definitions
- Blast Crisis
- Chronic Myelogenous Leukemia late stage progression to >20% blasts in blood or marrow
- Results in very high White Blood Cell Counts, Anemia, infection risk, Leukostasis, Tumor Lysis Syndrome
III. Pathophysiology
- Late complication of Chronic Myelogenous Leukemia (CML)
- Rapid increase in immature White Blood Cells (Lymphoblasts) in the blood and Bone Marrow
- Lymphoblasts increase in the Bone Marrow at the expense of other cell lines
- White Blood Cells increase causing Leukostasis in the microvasculature
- Results in end organ decreased perfusion
IV. Findings
- Leukostasis
-
Bone Marrow infiltration related findings
- Gingival Bleeding, easy Bruising or Petechiae
- Fatigue
- Night Sweats
- Bone pain
V. Labs
-
Complete Blood Count with differential
- Lymphoblasts represent >20% of Lymphocytes in Blast Crisis
- Lymphoblasts are typically absent from blood
- Anemia
- Thrombocytopenia
-
Peripheral Smear
- Lymphoblasts prominent with associated Anemia and Thrombocytopenia
-
Bone Marrow Biopsy
- Lymphoblasts represent >20% of Lymphocytes in Blast Crisis
- Lymphoblasts are typically 5% of Bone MarrowLymphocytes
- Other lab findings related to high blood cell turnover
- Serum Uric Acid increased
- Lactate Dehydrogenase (LDH) increased
VI. Differential Diagnosis
- Chronic Myelogenous Leukemia (CML, with Blast Crisis)
- Acute Myelogenous Leukemia (AML, new onset)
- Acute Promyelocytic Leukemia (APML)
- Associated with Disseminated Intravascular Coagulation (DIC)
- Lab findings include increased INR/PTT, D-Dimer and decreased Fibrinogen and Platelet Count
VII. Management
- Emergent hematology oncology Consultation
- Acute complication management (see below)
- Leukostasis
- Acute infections
- Infection is the most common cause of death in Blast Crisis
- Hemorrhage Management
- Bleeding complications are the second most common cause of death in Blast Crisis
- Consider All-Trans-Retinoic Acid (ATRA) if Acute Promyelocytic Leukemia (APML) is suspected
- Promotes transition of Promyelocytes to differentiate into Neutrophils
- Reduces Disseminated Intravascular Coagulation (DIC) severity
VIII. Complications
-
Anemia
- Avoid Blood Transfusion if possible (may worsen Blast Crisis)
- pRBC Transfuse for hemodynamic instability or uncontrolled Hemorrhage
-
Thrombocytopenia
- Spontaneous Intracranial Hemorrhage risk when Platelet Count <20,000
- Platelet Transfusion for Platelet Count <20,000 (<50,000 if current bleeding)
- Increased infection risk
- Functional Neutropenia or Immunocompromised state
- Treat focal infections with broad spectrum Antibiotics
-
Leukostasis (Hyperviscosity Syndrome)
- See Leukostasis for management
- CNS and cardiac hypoperfusion from sludging of white cells (>50,000/ul)
- Presents with Altered Mental Status, CVA, CHF or Pulmonary Edema
-
Tumor Lysis Syndrome
- See Tumor Lysis Syndrome for management
- Presents with fever, Fatigue, weakness, Nausea, Vomiting
- Rapid cell death and turnover resulting Electrolyte abnormalities
IX. References
- Bierowski and Nyalakonda (2025) Crit Dec Emerg Med 39(6): 4-21
- Dubbs and Swaminathan in Swadron (2021) Crit Dec Emerg Med 21(12): 18-20