Summary about Disease
Blast crisis, also known as accelerated phase or acute leukemia transformation, is a late stage in chronic myelogenous leukemia (CML) or, less frequently, myelodysplastic syndrome (MDS) and other myeloproliferative neoplasms (MPNs). It signifies a transformation to an aggressive acute leukemia, characterized by a rapid increase in the number of immature blood cells (blasts) in the bone marrow and blood. This leads to bone marrow failure and associated complications.
Symptoms
The symptoms of blast crisis are similar to those of acute leukemia and can include:
Fatigue and weakness
Fever
Night sweats
Bone pain
Easy bruising or bleeding (e.g., nosebleeds, gum bleeding)
Pale skin
Shortness of breath
Enlarged spleen (splenomegaly)
Enlarged liver (hepatomegaly)
Infections
Weight loss
Causes
Blast crisis is a progression from an existing chronic myeloproliferative neoplasm (most commonly CML). It results from the accumulation of additional genetic mutations in the leukemic cells that make them resistant to treatment and allow them to proliferate uncontrollably. In CML, the initial cause is the Philadelphia chromosome, which leads to the BCR-ABL1 fusion gene. Further mutations in genes involved in cell growth and differentiation drive the transformation to blast crisis. Rarely, other diseases transform to blast crisis, such as Myelodysplastic Syndromes or Essential Thrombocythemia.
Medicine Used
Treatment for blast crisis is similar to that of acute leukemia and may include:
Chemotherapy: Intensive chemotherapy regimens are used to kill the cancerous blast cells. Examples include cytarabine, anthracyclines (e.g., daunorubicin, idarubicin), and other agents.
Tyrosine Kinase Inhibitors (TKIs): In CML blast crisis, if the blasts express the BCR-ABL1 fusion gene, TKIs like imatinib, dasatinib, nilotinib, bosutinib, or ponatinib may be used, particularly if the patient was previously responsive to them.
Stem Cell Transplantation (Bone Marrow Transplant): Allogeneic stem cell transplant, where stem cells are received from a matched donor, is often the best chance for long-term remission. This is performed after initial remission is obtained with chemotherapy.
Targeted Therapies: Depending on the specific mutations found in the blast cells, targeted therapies may be used.
Clinical Trials: Participation in clinical trials may provide access to novel treatment options.
Is Communicable
Blast crisis is not communicable. It is not an infectious disease and cannot be spread from person to person.
Precautions
Precautions during treatment for blast crisis focus on managing the complications of the disease and the side effects of treatment:
Infection Control: Because chemotherapy and stem cell transplant suppress the immune system, strict infection control measures are crucial. This includes frequent hand washing, avoiding crowds, and prompt treatment of any signs of infection.
Bleeding Precautions: Due to low platelet counts, precautions to prevent bleeding are important. This includes avoiding activities that may cause injury, using a soft toothbrush, and monitoring for signs of bleeding.
Nutritional Support: Maintaining adequate nutrition is essential to support the body during treatment.
Psychological Support: Blast crisis and its treatment can be emotionally challenging, so psychological support and counseling are important.
Medication Adherence: Taking medications as prescribed and attending all medical appointments are critical for optimal outcomes.
How long does an outbreak last?
Blast crisis is not an "outbreak" in the traditional sense of an infectious disease. It's a progression of an existing hematological malignancy. The duration of blast crisis depends on the individual response to treatment. Without treatment, it is rapidly fatal, typically within a few months. With treatment, the goal is to achieve remission, but the length of remission varies greatly. The overall survival rate for blast crisis is unfortunately low compared to chronic phase CML.
How is it diagnosed?
Blast crisis is diagnosed through a combination of tests:
Complete Blood Count (CBC): Shows elevated white blood cell count with a high percentage of blast cells.
Bone Marrow Aspiration and Biopsy: Confirms the diagnosis by showing an increased number of blast cells (usually >20% in the bone marrow). It also helps to assess for other abnormalities.
Cytogenetic and Molecular Testing: Identifies the Philadelphia chromosome (BCR-ABL1) in CML blast crisis and other genetic mutations that may be present.
Flow Cytometry: Helps to identify the type of blast cells (myeloid or lymphoid) and their surface markers.
Timeline of Symptoms
The timeline of symptoms in blast crisis is often rapid. Patients often experience a quick worsening of symptoms.
Early Stages (Weeks to Months): Subtle symptoms like fatigue, weakness, and weight loss may be present but are often attributed to other causes.
Progression (Days to Weeks): More pronounced symptoms develop, including fever, night sweats, bone pain, easy bleeding and bruising, and shortness of breath. The CBC will show worsening counts.
Late Stages (Days): The disease progresses rapidly, leading to severe bone marrow failure, life-threatening infections, and bleeding complications.
Important Considerations
Prognosis: Blast crisis has a poor prognosis compared to the chronic phase of CML or other MPNs.
Treatment Intensity: Treatment is aggressive and often requires hospitalization.
Complications: Patients are at high risk for complications such as infections, bleeding, and tumor lysis syndrome.
Stem Cell Transplant: Allogeneic stem cell transplant offers the best chance for long-term survival but carries significant risks.
Psychological Impact: The diagnosis and treatment of blast crisis can have a significant psychological impact on patients and their families, requiring comprehensive supportive care.
Palliative Care: If curative treatment is not possible, palliative care focuses on managing symptoms and improving quality of life.