CML, leukocytosis, and leukostasis – 8/14/18

Yours truly presented a case of a middle aged man admitted for traumatic rib fracture overnight and found to have a WBC of 368k with cytogenetics consistent with CML!

Clinical Pearls

  • WBC > 100k is most consistent with leukemia.
  • WBC up to 75k can be seen with C diff infection.
  • Leukostasis is most commonly associated with AML > ALL > CML > CLL and defined as hyperleukocytosis with evidence of end-organ damage (CNS, renal, pulm)
    • Hematologic emergency!
    • Treatment is three-fold:
      • cytoreduction: leukapharesis, hydroxyurea, TKI (especially for CML), induction chemo (with other malignancies)
      • FLUIDS
      • prevention of tumor lysis syndrome (another heme emergency): allopurinol, FLUIDS

Differential for leukocytosis:

Blood Cell Lineage

  • Neutrophilia (most common, >7000/mm^3)
    • Infections
    • Stress/trauma
    • Chronic inflammation
    • Meds
    • Leukemias
  • Lymphocytosis (>4500/mm^3)
    • Pertussis
    • Syphilis
    • Viral infections
    • Hypersensitivity reactions
    • Leukemias/lymphomas
  • Monocytosis (>880/mm^3)
      • EBV
      • TB
      • Fungal disease
      • Autoimmune disease
      • Splenectomy
      • Protozoan/rickettsial infections
      • Leukemias


  • Eosinophilia (>500/mm^3):
    • Neoplasm
    • Adrenal insufficiency
    • Asthma/atopy
    • Collagen vascular disease
    • Parasites


  • Refer to this and this prior posts on the blog for all the details!
  • Some details to highlight
    • Smear tends to show lots of immature myeloid cells from many different stages of maturation (some blasts, metamyelocytes, myelocytes, bands, and mature neutrophils)
    • If >20% blasts, then think AML


  • Defined as symptomatic hyperleukocytosis and is a hematologic emergency!
  • Mortality rate is can be as high as 40% within the first week of presentation.
  • Clinical manifestations of ischemia primarily in CNS, lungs, and kidneys.  Can also see limb ischemia and priapism.
  • Malignancies at highest risk of leukostasis in order of prevalence:
    • AML (WBC >50k)
    • ALL (WBC >100k, though tends to present with TLS and DIC much more commonly than leukostasis)
    • CML (WBC >100k)
    • CLL (WBC >400k)
  • Treatment:
    • FLUIDS, lots and lots of fluids
    • Cytoreduction: lowers the WBC
      • Leukapharesis: not readily available as it requires a dialysis line and trained nursing staff
      • Hydroxyurea: to lower the WBC
      • Tyrosine kinase inhibitors (especially for CML related leukostasis)
      • Induction chemo (for non-CML related leukostasis)
    • Prevent tumor lysis syndrome:
      • FLUIDS
      • Allopurinol
    • In hemodynamically stable patients AVOID TRANSFUSION – it’s like adding fuel to the fire and can worsen ischemia.

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