See also

Blood product prescription 

Stroke

Key points

1. Early consultation with oncology is important
2. Children with high count leukaemia (hyperleukocytosis) are at risk of death or serious complications due to leukostasis/hyperviscosity syndrome
3. Avoid red cell transfusion unless directed by oncology
4. Maintain platelets >50 x 10⁹/L. Platelet consumption can be rapid, and multiple transfusions may be needed per day
5. Correct coagulopathy

Background

• Hyperleukocytosis is defined as a WCC >100 x 10⁹/L. Hyperleukocytosis should prompt consideration of possible acute leukaemia.
• Leukostasis (symptomatic hyperleukocytosis) is a clinical diagnosis in which respiratory distress, CNS abnormalities or other organ dysfunction is attributed to hyperleukocytosis
• Hyperleukocytosis is associated with serious and potentially fatal complications, including
  • ischaemic and haemorrhagic strokes
  • pulmonary or renal thrombosis and infarction
  • tumour lysis syndrome
  • coagulopathy: disseminated intravascular coagulation
• The frequency of complications from hyperleukocytosis depends on the type of leukaemia, some types of acute myeloid leukaemia (AML) can be associated with risks of hyperleukocytosis at WCC ≥50 x 10⁹/L

Assessment

The main risks are bleeding or thrombosis. Organs most frequently affected are the brain and lung

History

• Visual disturbance, dizziness, tinnitus, behaviour changes, altered conscious state

Examination

• Altered mental status, ataxia, papilloedema, retinal abnormalities, clinical signs of raised intracranial pressure
• Increased work of breathing

Management

Early consultation with oncology is important, with retrieval to a tertiary centre and consideration of PICU for all children with hyperleukocytosis

Investigations

Discuss with oncology prior to further blood collection to help prioritise time sensitive investigations

Blood tests usually required include

• FBE and film
• Group and hold
• UEC
• LFT
• CMP
• LDH
• Coagulation screen, including fibrinogen. An adjusted coagulation tube may be required; if there is significant anaemia (haematocrit <0.21). Discuss with the laboratory prior to taking blood
• Uric acid
• G6PD assay

Imaging

• CXR
• Consider neuroimaging, if neurological signs or symptoms present

Monitoring

• Continuous saturations monitoring recommended. Consider cardiac monitoring
• 4 hourly neurological observations
• 6 hourly FBE, UEC, CMP, uric acid +/- coagulation studies

Treatment

1. Commence hyperhydration at 125 mL/m²/hr (or double maintenance rate) without added potassium (0.9% NaCl with 5% Dextrose)
2. Maintain platelets >50 x 10⁹/L. Platelet consumption can be extremely rapid, and multiple transfusions may be needed per day
3. Correct coagulopathy: maintain INR <2.0, APTT <80 and fibrinogen >1.0. See Blood product prescription
4. Red cell transfusions should be avoided unless suggested by oncology, and limited to 5-10 mL/kg to minimise risk of hyperviscosity
5. Oncology may recommend commencement of allopurinol or rasburicase

Consider consultation with local paediatric team when

Hyperleukocytosis is suspected

Consider transfer when

Early consultation with oncology is important, with retrieval to a tertiary centre and consideration of PICU for all children with hyperleukocytosis

For emergency advice and paediatric or neonatal ICU transfers, see Retrieval Services

Last updated October 2025