Hypoxia and Hyperleukocytosis

Today, we discussed a case of acute respiratory distress in a patient with newly diagnosed T-cell prolymphocytic leukemia with a white count of >600K and recent initiation of alemtuzumab (monoclonal Ab that binds CD 52 on lymphocytes as well as monocytes, macrophages,etc leading to antibody-dependent lysis of malignant cells).

An interesting differential was generated for this scenario:  

  • Anaphylaxis
  • Leukostasis (medical emergency most common in AML or CML with blast crisis--not typically with mature lymphocytes--involving hyperleukocytosis with end organ damage/decreased tissue perfusion with early death mainly related to lung or CNS involvement)
  • Pulmonary embolism
  • Infection/sepsis
  • Malignant effusions (including pericardial and pleural)

This patient was ultimately thought to have anaphylaxis from the recent alemtuzumab infusion and was given IM epinephrine. Check out a nice review on anaphylaxis from the BMJ here.