leukaemia

leukaemia

1. acute lymphoblastic leukaemia

   • =80% of leukaemia in kids
   • clinical presentation
     • peaks @ 2-5 years
     • results from disseminated disease & systemic ill health from infiltration of bone marrow or other organs w/ leukaemic blast cells
       • general
         • malaise
         • anorexia
       • bone marrow infiltration
         • anaemia
           • pallor, lethargy
         • neutropenia
           • infection
         • thrombocytopenia
           • bruising, petechiae, nose bleeds
         • bone pain
       • reticulo-endothelial infiltration
         • hepatosplenomegaly
         • lymphadenopathy, superior mediastinal obstruction (uncommon)
       • other organ infiltration (rare @ diag, more often @ relapse)
         • CNS
           • headaches
           • vomiting
           • nerve palsies
         • testes
           • testicular enlargement
     • in most kids, ALL presents insidiously over several weeks
       • in some presentation& progress is rapid
   • Ix
     • abnormal FBC in most
       • low Hb
       • thrombocytopenia
       • evidence of circulating leukaemic blast cells
     • bone marrow exam
       • to confirm diag
       • to ID immunological & cytogenetic characteristics that give prognostic info
     • CXR
       • to ID mediastinal mass
         • characteristic of T cell disease
     • morphological classification
       • for ALL & AML
       • + immunological phenotyping to further subclassify ALL
         • common subtype (75%)
         • T cell subtype (15%)
   • Mx
     • prognostic factors (& also indicate intensity of therapy)
       • age
         • high risk features
           • <1 year or > 10 years old
       • tumour load (measured by WBC)
         • high risk features
           • > 50 x10^9/L
       • cytogenetic/molecular genetic abnormalities in tumour cells
         • high risk features
           • e.g. MLL rearrangement, t(4:11), hypodiploidy (<44 chromosomes)
       • speed of response to initial chemo
         • high risk features
           • persistence of leukaemic blasts in bone marrow
       • minimal residual disease (submicroscopic levels of leukaemia detected by PCR)
         • high risk feature
           • high
     • remission induction
       • before Rx anaemia may need correcting
         • blood transfusion
       • minimise risk of bleeding
         • platelet transfusion
       • treat infection
       • additional hydration & allopurinol (or urate oxidase when WCC high & risk greater)
         • to protect renal function vs effects of rapid cell lysis
       • remission implies eradication of leukaemic blasts & restoration of normal marrow function
       • 4 weeks of combo chemo given
         • current schedules reach remission rates of 95%
     • intensification
       • block of chemo given to consolidate remission
       • improves cure rates but w/ increased toxicity
     • central nervous sys
       • cytotoxic drugs penetrate poorly into CNS
       • additional Rx w/ intrathecal chemo
         • to prevent CNS relapse
         • as leukaemic cells in CNS may survive effective systemic Rx
     • continuing therapy
       • moderate intensity chemo continued up to 3 years from diag
       • routine co-trimoxazole prophylaxis
         • to prevent Pneumocystitis carinii pneumonia
     • treatment of relapse
       • high dose chemo, often + total body irradiation + bone marrow transplantation
         • alternative to chemo after a relapse

2. acute myeloid leukaemia

3. acute non-lymphocytic leukaemia

4. chronic myeloid leukaemia & other myeloproliferative disorders

   • rare