Acute Myeloid Leukaemia

Cancer of the myeloid line of blood cells (progenitor cell for granulocytes, monocytes, erythrocytes or platelets)

Aetiology

  • Most common acute leukemia in adults
  • Median age: >65 years
  • Can occur at any age
  • Associated with:
    • Prior chemotherapy / radiotherapy (therapy-related AML)
    • Myelodysplastic syndrome
    • Benzene exposure
    • Down syndrome (specific subtypes)

Clinical presentation

Bone Marrow Failure
  • Fatigue, pallor → anemia
  • Petechiae, bleeding → thrombocytopenia
  • Fever, infections → neutropenia
Leukemic Infiltration
  • Hepatosplenomegaly
  • Lymphadenopathy (less than ALL)
  • Gingival hypertrophy (M4, M5)
  • Skin nodules (leukemia cutis)
Special Presentation
  • APL (M3) → bleeding, DIC

FAB Classification

Type
Subtype
Key Feature
M0
Minimally differentiated
MPO negative
M1
Without maturation
MPO positive
M2
With maturation
t(8;21)
M3
Acute promyelocytic leukemia (APL)
t(15;17), DIC
M4
Myelomonocytic
Gingival infiltration
M5
Monocytic
CNS, skin involvement
M6
Erythroleukemia
Abnormal erythroid precursors
M7
Megakaryoblastic
Associated with Down syndrome

Investigations

  • Blood count and film
    • Reduction in normal cells
    • Presence of abnormal cells (‘blasts’) - large size, high nuclear:cytoplasmic ratio, prominent nucleolus
      • By definition an acute leukaemia involves an excess of ‘blasts’ (>/=20) in either the peripheral blood or bone marrow
    • Blast cells have rods inside their cytoplasm that are named Auer rods
      • notion image
  • Coagulation screen
  • Bone marrow aspirate
    • Hypercellular
    • ≥20% myeloblasts
    • Suppressed normal lineages

Management

  • Multi-agent chemotherapy
    • Between 2-4 cycles of chemotherapy
    • Prolonged hospitalisation
    • Targeted treatments in subsets
    • Hickman line used to provide long-term central venous access

Complications

Complications of disease

  • Anaemia
  • Neutropenia
    • Increased severity and duration of infections
    • Gram negative bacteria can cause fulminant life-threatening sepsis in neutropenic patients
    • Patients also susceptible to fungal infections
  • Thrombocytopenia
    • Bleeding - purpura, petechiae

Complications of treatment

  • N+V
  • Hair loss
  • Liver, renal dysfunction
  • Tumour lysis syndrome (during first course of treatment)
  • Infection
    • Bacterial: empirical treatment with broad spectrum antibiotics (particularly covering gram negatives) as soon as neutropenic fever
    • Fungal - if prolonged neutropenia and persisting fever unresponsive to anti-bacterial agents
    • Protozoal e.g. PJP (more relevant in ALL therapy)
  • Late effects e.g. loss of fertility, cardiomyopathy with anthracyclines