Haem: Leukaemia Flashcards
Define Acute Leukaemia
Neoplastic process affecting blood precursor cells (blast cells)
“Acute”: progressing rapidly, resulting in excess immature blood cells, and fatal
Pathoneumonic sign of Acute leukaemia when analysing bone marrow
Immature blast cells >20% of bone marrow cells
2 types of acute leukaemia
Acute Lymphocytic Leukaemia
Mutations in lymphoblast cell
Acute Myeloid Leukaemia
Mutations in the pluripotent haematopoetic stem cell OR multipotent myeloid stem cell
Clinical features seen in all types of Acute leukaemia
Bone Marrow Failure
- Anaemia (signs/sx of anaemia)
- Infection (neutropenia)
- Bleeding (thrombocytopenia)
Organ Infiltration of blast cells
- Hepatosplenomegaly
- Lymphadenopathy (ALL>AML)
- Others: Bone (ALL>AML), CNS (ALL>AML), Skin, Gums
Aetiology of Acute Leukaemias
Most times it is unknown however chromosome aberrations are commonly implicated:
- Duplication → resulting in increased copies of proto-oncogenes
- Inversion/Translocation → resutling in fusion genes which are pro-oncogenic
- Chromosomal loss → loss of tumour suppressor genes
Other commonly implicated aetiological factors:
- Ionising radiation (leading to DNA mutations)
- Cytotoxic drugs (leading to DNA mutations)
- Down’s Syndrome (AML>ALL)
2 Types of DNA abnormalities required for leukaemogenesis
Type 1: Promote cell proliferation
Type 2: Block cell differentiation
How do you diagnose Acute leukaemia
- Morphology of cells: increased blast cells, Auer rodes (AML!!)
- Immunophenotyping: differentiates between AML and ALL through CD receptors as well as ALL B-cell or T-cell predominent
- Cytogenics: identify chromosomal translocations for specific targetted treatment (e.g. Philadelphia chromosome in ALL)
Differentiating between ALL and AML:
Epidemiology
Differentiating between ALL and AML:
Clinical Features
Differentiating between ALL and AML:
Investigations
Differentiating between ALL and AML:
Management
Chronic Myeloid Leukaemia
Define and outline which cell carries leukaemogenic mutation
Myeloproliferative disease - with mutations in haematopoetic stem cell. Haematopoetic stem cell mutations (commonly the philadelphia chromosome) steer it into going down the myeloid differentiation pathway.
Unlike acute leukaemia, in chronic leukaemia you have partial maturation.
Chronic Myeloid Leukaemia
Age of onset
Middle-aged → 40-60s
Chronic Myeloid Leukaemia
Clinical feature
CLASSIC CLINICAL VIGNETTE:
Present feeling unwell, weight loss, recurrent infections and easy bruising.
On examination → MASSIVE splenomegaly (EXAM BUZZWORD)
Bloods → neutrophilia!!
Chronic Myeloid Leukaemia
Investigations when suspecting CML
FBC:
- Massively elevated WBC (50-500x109)
- Neutrophilia
- Basophilia
Blood film:
- Neutrophilia
- Basophilia
- Myelocytes (if you see myeloblasts you are thinking more acute CML)
→ biphasic peak where there is increased myelocytes and basophils/neutrophils
Bone Marrow Biopsy
- hypercellular BM with myelocytes (NOT myeloblasts) and mature granulocytic cells.
- myelobasts at <5% (unless in acute crisis)
FISH
- Philadelphia chromosome +ve in 80% of cases (translocation 9;22)
RQ-PCR
- BCR-ABL fusion gene (arising from the philadelphia chromosome)