Hyperleukocytosis and Leukostasis Management (ATS 2025)

Algorithm Steps

1. ▶

   Start

   Hyperleukocytosis Detected

   WBC >100,000/µL in setting of leukemia

   1. ◆

      Decision

      Leukemia Type

      AML/CML blast crisis vs ALL/CLL

      • AML: Highest risk of leukostasis (15-20% mortality)
      • CML blast crisis: High risk
      • ALL: Lower risk but can occur
      • CLL: Very rare to cause leukostasis despite high counts
      1. ●

         Action

         Screen for Leukostasis Symptoms

         End-organ manifestations

         • Pulmonary: Dyspnea, hypoxia, diffuse infiltrates
         • CNS: Confusion, headache, visual changes, stroke
         • Hemorrhage: Retinal, pulmonary, CNS
         • Note: Leukostasis can occur at WBC <100k
         • Cell type more predictive than count
         1. ◆

            Decision

            Symptomatic Leukostasis?

            Respiratory or neurological symptoms

            1. ⚠

               Warning

               SYMPTOMATIC - Emergency

               Immediate intervention required

               • ICU admission
               • Supplemental oxygen
               • AVOID RBC transfusion if possible (increases viscosity)
               • Consider mechanical ventilation if severe
               1. ●

                  Action

                  Tumor Lysis Syndrome Prevention

                  Critical with cytoreduction

                  • Aggressive IV hydration 2-3 L/day
                  • Allopurinol 300-600mg daily, OR
                  • Rasburicase 0.2mg/kg if high uric acid (avoid in G6PD)
                  • Monitor electrolytes, uric acid, creatinine q6h
                  • Avoid potassium in IV fluids initially
                  1. ●

                     Action

                     Cytoreduction

                     Reduce WBC count rapidly

                     • Hydroxyurea 50-100 mg/kg/day in divided doses
                     • Can give up to 10g/day in emergency
                     • Low-dose cytarabine as alternative
                     • Definitive chemotherapy once diagnosis confirmed
                     • Hematology/oncology consultation
                     1. ◆

                        Decision

                        Consider Leukapheresis?

                        Controversial - not routine

                        • May be considered if:
                        • - Symptomatic leukostasis
                        • - Unable to tolerate chemotherapy
                        • - Bridge to definitive treatment
                        • NOT routinely recommended
                        • AVOID in APL
                        1. ●

                           Action

                           Proceed with Leukapheresis

                           If available and indicated

                           • Removes 30-60% WBC per session
                           • May need daily sessions
                           • Temporary measure only
                           • Continue hydroxyurea concurrently
                           1. ●

                              Action

                              Monitoring

                              Frequent reassessment

                              • CBC q6-12h initially
                              • Electrolytes, uric acid q6h
                              • Continuous pulse oximetry
                              • Neurologic checks
                              • Target WBC <50-100k before definitive chemo
                              1. ✓

                                 Outcome

                                 Leukostasis Managed

                                 Transition to definitive leukemia treatment

                        2. ●

                           Action

                           Medical Management Only

                           Continue cytoreduction and supportive care

            2. ●

               Action

               Asymptomatic Hyperleukocytosis

               Preventive management

               • High risk of developing leukostasis
               • Monitor closely in hospital
               • Proceed with cytoreduction