# Hyperleukocytosis and leukostasis in acute leukaemia: supportive care, cytoreduction and leukapheresis

Source: https://onco.cc/protocols/hyperleukocytosis-leukostasis/  
OnCo record `hyperleukocytosis-leukostasis` (Protocol). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

In some leukaemias the white cell count is so high that the blood thickens and blocks small vessels in the lungs, brain and kidneys. This leukostasis is an emergency. The cells are brought down quickly with hydroxyurea and then chemotherapy; sometimes a machine filters them out. Blood transfusions are avoided unless really needed, because they thicken the blood further.

## Summary

Hyperleukocytosis is a white cell count above 100,000/µL from leukaemic proliferation; leukostasis is end-organ injury from it, which can occur at lower counts and is commoner in AML than ALL because myeloid blasts are larger (ATS Scholar 2025). The lungs, kidneys and brain are most affected; intracranial haemorrhage is the most feared complication. Tumour lysis syndrome (up to 10%) and DIC (30 to 40%) accompany it. Diagnosis is usually presumptive. There should be a low threshold for intensive care.

Supportive care: fluids with close fluid-balance monitoring, electrolytes and uric acid at least every 6 hours, allopurinol or rasburicase, red cell transfusion only for symptomatic anaemia because it raises viscosity, and prompt platelets, plasma and fibrinogen for DIC. Cytoreduction: hydroxyurea before induction chemotherapy; all-trans retinoic acid at once if acute promyelocytic leukaemia is suspected. Leukapheresis can be considered but is institution-specific; a 2026 meta-analysis of 13 retrospective studies (1406 patients in the main analysis) found no clear reduction in 30-day mortality (OR 0.94, 95% CI 0.65 to 1.34; very low certainty). Red cell exchange is reported as an alternative for rapid leukoreduction (Blood 2024). ASFA's tenth edition (2026) categorises leukocytapheresis, but its category could not be read.

## Fields

- Kind: Protocol
- Last checked: 2026-11-11
- Also known as: leukostasis; hyperleukocytosis; white cell count over 100; leukapheresis for AML; leukoreduction
- Tags: protocol; acute-oncology; oncological-emergency; haematology

## Connected records

- protocols: [Tumour lysis syndrome: risk assessment, prophylaxis and treatment](https://onco.cc/protocols/tumour-lysis-syndrome-prevention-and-treatment/)
- cancers: [Acute lymphoblastic leukaemia](https://onco.cc/cancers/all-leukemia/), [Acute myeloid leukaemia](https://onco.cc/cancers/aml/), [Leukaemia (all types)](https://onco.cc/cancers/leukaemia/)
- drugs: [Allopurinol](https://onco.cc/drugs/allopurinol/), [Cytarabine](https://onco.cc/drugs/cytarabine/), [Hydroxyurea (hydroxycarbamide)](https://onco.cc/drugs/hydroxyurea/), [Rasburicase](https://onco.cc/drugs/rasburicase/), [Tretinoin (all-trans retinoic acid, ATRA)](https://onco.cc/drugs/tretinoin-atra/)
- terms: [Apheresis (leukapheresis)](https://onco.cc/terms/apheresis/), [Tumour lysis syndrome (TLS)](https://onco.cc/terms/tumor-lysis-syndrome/)

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