Abstract
We present the case of a 40-day-old female infant with acute lymphoblastic leukemia and KMT2 rearrangement. Laboratory data included a white blood cell (WBC) count of 1,730×103/μL and leukocrit of 43%. We conducted mechanical ventilation, followed by exchange transfusion (ET) immediately after admission, because her leukostasis (symptomatic hyperleukocytosis) required emergency care. During the procedure, we observed hyperphosphatemia and hypocalcemia. The WBC count rapidly declined, and it decreased further to 3,100/μL on treatment day 9. We initiated multi-agent chemotherapy on the same day. We eventually conducted cord blood transplantation at 6 months of age, and she has remained in remission for 1 year since. Since subdural hematoma was observed, a slight developmental delay was noted (development quotient of 69 at 18 months of age), but she is gradually catching up with normal children. ET was effective for smooth transition of induction therapy. We emphasize the need for long-term follow-up since leukostasis might affect the brain microenvironment and, consequently, neurological development.
