Another Emergent Cause of Headache.

We present a case of a subacute headache related to leukostasis secondary to accelerated chronic myeloid leukemia (CML), which required white blood cell (WBC) reduction in the emergency department. A 28-year-old male presented to the emergency department with a chronic headache found to be secondary to leukostasis from accelerated CML with a white blood cell count of 801,000 and 9% blasts. He had bilateral retinal hemorrhage and a headache associated with elevated intracranial pressure. Hydroxyurea and allopurinol were initiated in the emergency department and the patient was eventually transitioned to a tyrosine kinase inhibitor as outpatient therapy. Headaches are a frequent cause of emergency department visits, and this case illustrates another possible etiology of headache requiring emergent intervention.