Updated: 6/21/2021

Leukemia

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  • summary
    • Leukemia is a malignant neoplastic proliferation of lymphocytes and lymphocyte precursors. Patients typically present before the age of 4 with recurrent infections, bleeding, fatigue, and lymphadenopathy. 
    • Diagnosis is made with a bone marrow biopsy.
    • Treatment is usually chemotherapy. 
  • Etiology
    • Forms include
      • acute lymphocytic leukemia (ALL)
        • neoplastic proliferation of lymphocytes
      • actue myeloblastic leukemia (AML)
        • neoplastic proliferation of myeloblasts
      • chronic myelocytic leukemia (CML)
        • neoplastic mature myeloid cells (granulocytes)
      • chronic lymphocytic leukemia (CLL)
        • neoplastic proliferation of naive B cells
  • Classification
    • ALL
      • represents 80% of cases of leukemia
      • peak incidence of 4 years of age
      • causes dimeralization of bones, periostitis, and lytic lesions
      • positive TdT nuclear staining
      • T-ALL
        • proliferation of T-lymphocytes
        • presents in teenagers
      • B-ALL
        • proliferation of B-lymphocytes
        • 12;21 translocation most commonly seen in children
        • 9;22 translocation most commonly seen in adults
    • AML
      • most commonly seen in older adults (5th-6th decade)
      • marrow failure secondary to crowding out of normal hematopoiesis by neoplastic proliferation
      • myeloblasts with Auer rods
      • Acute Promyelocytic Leukemia (APL)
        • caused by 15;17 translocation
          • disrupts retinoic acid receptor (RAR) required for myeloblast maturation
      • Acute megakaryoblastic leukemia
        • associated with Down syndrome
          • younger than 5 years
      • Acute monocytic leukemia
        • infiltration of the gums
    • CML
      • onset usually in older adults (5th-6th decade)
      • 9;22 translocation
        • known as the Philadelphia chromosome
        • results in a fusion tyrosine kinase with increased activity (bcr-abl)
        • increased levels of bcr-abl leads to ↑ cell division and inhibition of apoptosis
    • CLL
      • commonly seen in older adults (5th-6th decade)
      • insidious onset of symptoms
      • smudge cells on peripheral smear
  • Presentation
    • Symptoms
      • recurrent infections
      • bleeding
      • fatigue
      • lymphadenopathy (more common in CLL)
    • Physical exam
      • hepatosplenomegaly
        • secondary to leukemic infiltrate
      • lymphadenopathy
        • secondary to leukemic infiltrate
  • Treatment
    • Nonoperative
      • chemotherapy
        • T-ALL & B-ALL
        • may predispose to pathologic fractures
        • all-trans-retinoic acidfor APL (AML subtype)
        • imatinib for CML
Evidence (1)
EXPERT COMMENTS (4)
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