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Hyperleucocytosis in the oncology patient

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Shared care information

If a patient presents with hyperleucocytosis and is asymptomatic, discuss with the paediatric oncologist on call and arrange for urgent transfer.

If a patient has any of the symptoms listed below, then again discuss the patient with the paediatric oncologist as they may recommend commencement of tumour lysis prevention or other treatment prior to transfer. Red cell transfusions should be avoided.

Definition and incidence

Hyperleucocytosis is a presenting WBC >100 x109/L.

  • Occurs in acute leukaemia (AML~15% (especially acute promyelocytic and monoblastic); ALL~10%) and CML
  • More common in infant leukaemias
  • May be symptomatic or asymptomatic. Symptoms of leucostasis occur more commonly in AML as the blasts are larger.

Pathophysiology

The potential problems with hyperleucocytosis are:

Hyperleucocytosis increases blood viscosity which is dependent on:

  • packed red cell volume and
  • white cell volume.

In addition, blasts are not easily deformed. The net result is cell trapping in the microvasculature with microthrombi leading to poor tissue perfusion and acidosis.

Clinical presentation

  • CNS - confusion, headache, blurred vision, papilloedema, cranial nerve palsies, LOC
  • Lung - dyspnoea, hypoxia, acidosis (CXR will usually be normal or have nonspecific infiltrates)
  • Renal - renal impairment, renal vein thrombosis
  • GIT - haemorrhage, bowel infarction
  • Priapism
  • Eyes - papilloedema, retinal vein thrombosis, retinal haemorrhages
  • Fever
  • DIC
  • Biochemistry abnormalities (as for tumour lysis syndrome).

Note: Spurious hyperkalaemia or hyperglycaemia may occur with high count leukaemia when blasts lyse and release K+ or glucose after the blood is taken. If the K+ or glucose comes back raised and you suspect a spurious result:

  • Aspirate blood slowly through large-bore needle, transport quickly to lab (not through Lansom tube) and ensure an atraumatic, slow spin-down (discuss with lab).

Management

  • Discuss with paediatric oncologist on call.
  • Establish the diagnosis on peripheral blood morphology and immunophenotyping. Take additional blood for cytogenetics and molecular studies.
  • BMA and LP can be deferred in very unwell patients.
  • Establish central venous access.
  • CXR and cardiac echo.
  • Consider transfer to HDU or ICU if metabolically unstable.
  • Commence hyperhydration with adequate urine output.
  • Commence rasburicase (or allpurinol if rasburicase not available). See rasburicase drug protocol.
  • Commence anti-leukaemic therapy as soon as possible once diagnosis has been established. This should be discussed with the paediatric oncologist on call. The usual dose of steroids is 60 mg/m2/day of prednisone but if there is a very high risk of tumour lysis syndrome a lower doses may be used.
  • Treat DIC if present (always do manual platelet count as count may be spuriously raised due to blast fragments). Platelet or FFP transfusion should have no significant effect on viscosity.
  • If patient has CNS symptoms keep platelets above 20 x109/L
  • Prevent and treat Tumour Lysis Syndrome aggressively.
  • Avoid red cell transfusion unless patient is clearly symptomatic from anaemia (this may be difficult to judge because of dyspnoea, etc., related to hyperleucocytosis). Transfuse 3-5 ml/kg over 3-4 hours and aim for max Hb around 80 g/L.

Leucopheresis

There is little evidence to support its use in paediatrics and its use may delay the initiation of anti-leukaemic therapy. It is contraindicated in APML as it may be associated with severe haemorrhage.

A decision on leucopheresis should be made by the treating oncologist on an individual patient basis. It may be considered in:

  • Symptomatic CNS or pulmonary leucostasis
  • ALL with WCC >400 x 109/L
  • AML with WCC >200 x 109/L

References

Lowe et al. Early complications in children with ALL presenting with hyperleukocytosis. Paed Blood Cancer. 2005;45:10-15.

AABB Hemapheresis Committee. Therapeutic apheresis: A summary of current indication categories endorsed by the AABB and the American society for apheresis. Transfusion. 2003;43:820-822.

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Document Control

  • Date last published: 01 October 2010
  • Document type: Clinical Guideline
  • Services responsible: National Child Cancer Network