Leukemoid reaction

Background

• Significant leukocytosis and neutrophilia in the absence of a hematologic malignancy
  • e.g. WBC ≥30-50 with ≥50% granulocytes

Differential Diagnosis

• Infections
  • Sepsis, pneumonia, urinary tract infection
  • Clostridioides difficile colitis (often quite high)
  • Disseminated tuberculosis
  • Severe shigellosis
  • Postpartum Clostridium sordellii
• Inflammation
  • Pancreatitis
  • Mesenteric inflammatory pseudotumor
• Malignancies
  • Carcinomas (lung, oropharyngeal, gastrointestinal, genitourinary)
  • Hodgkin lymphoma
  • Melanoma
  • Sarcoma
• Drugs
  • Corticosteroids
  • Minocycline
  • Recombinant hematopoietic growth factors
• Miscellaneous
  • Splenectomy
  • Ethylene glycol intoxication
  • Severe hemorrhage or acute hemolysis
  • Alcoholic steatohepatitis

Further Reading

• Leukemoid reaction: Spectrum and prognosis of 173 adult patients. Clin Infect Dis. 2013;57:e177. doi: 10.1093/cid/cit562
• An update on the etiology and diagnostic evaluation of a leukemoid reaction. Eur J Internal Med. 2006 Oct;17(6):394-8. doi: 10.1016/j.ejim.2006.04.004