{"entity":{"id":"leukostasis","kind":"term","name":"Leukostasis (a very high white cell count that blocks small blood vessels)","aka":["Hyperleucocytosis","Leucostasis","Leukaemic leukostasis"],"tldr":"In some leukaemias the white cell count climbs so high that the cells clog small blood vessels, mostly in the lungs and brain, causing breathlessness, confusion or headache. It is an emergency treated by bringing the count down quickly.","summary":"Hyperleukocytosis is usually defined as a white blood cell count above 100,000/µL in acute or chronic leukaemia; it can lead to leukostasis, disseminated intravascular coagulation and tumour lysis syndrome. Leukostasis is end-organ injury from microvascular obstruction by leukaemic blasts, a clinical diagnosis that can also occur at counts below 100,000/µL, with pulmonary, renal and cerebral involvement the commonest presentations. Supportive care includes intravenous hydration, uric acid-lowering drugs and cautious transfusion, since raising blood viscosity can worsen leukostasis. Hydroxyurea and cytarabine are used to lower the count before definitive induction chemotherapy; the benefit of leukapheresis on early outcomes has not been definitively shown and practice varies.","asOf":"2026-11-11","links":[{"label":"Approach to hyperleukocytosis and leukostasis: inpatient management strategies (J Hosp Med 2026)","url":"https://europepmc.org/article/MED/41058090"},{"label":"Pais et al., Management of leukostasis in acute myeloid leukemia (ATS Scholar 2025)","url":"https://europepmc.org/article/PMC/PMC12712836"}],"tags":["supportive-care-gaps-2026-11"],"related":[],"cancers":["aml"],"sections":[],"technologies":[],"targets":[],"drugs":["hydroxyurea","cytarabine"],"companies":[],"institutions":[],"pathways":[],"terms":["tumor-lysis-syndrome"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"provenance":{"editedBy":"OnCo supportive care gap fill (CDC, NHSN, SHEA, Society for Endocrinology, ESMO, MASCC, ASCO, ASTCT, NCI PDQ, Europe PMC)","editedOn":"2026-11-11"},"category":"Side effects"},"route":"/terms/leukostasis/","neighbours":{"cancer":[{"id":"aml","kind":"cancer","name":"Acute myeloid leukaemia","route":"/cancers/aml/"}],"drug":[{"id":"cytarabine","kind":"drug","name":"Cytarabine","route":"/drugs/cytarabine/"},{"id":"hydroxyurea","kind":"drug","name":"Hydroxyurea (hydroxycarbamide)","route":"/drugs/hydroxyurea/"}],"term":[{"id":"tumor-lysis-syndrome","kind":"term","name":"Tumour lysis syndrome (TLS)","route":"/terms/tumor-lysis-syndrome/"}]}}