What is the appropriate management for a 62-year-old female with leukocytosis?

Management of Leukocytosis in a 62-Year-Old Female

This patient requires immediate peripheral blood smear examination and clinical assessment to differentiate between benign reactive causes and hematologic malignancy, with urgent hematology referral if malignancy is suspected. 1, 2

Initial Diagnostic Evaluation

The WBC of 16.8 × 10⁹/L represents moderate leukocytosis that demands systematic evaluation. The elevated hemoglobin (15.8 g/dL) and hematocrit (48.1%) suggest possible polycythemia vera or secondary erythrocytosis, which can coexist with myeloproliferative disorders. 3

Critical First Steps

• Obtain peripheral blood smear immediately to identify blasts, dysplastic features, left shift, basophilia, and immature granulocytes 1, 2
• Assess for symptoms including fever, night sweats, weight loss, bruising, fatigue, or bleeding that suggest malignancy 1, 4
• Physical examination must specifically evaluate for splenomegaly, hepatomegaly, and lymphadenopathy 5, 6

Risk Stratification Based on Clinical Presentation

High-Risk Features Requiring Urgent Hematology Referral

• Presence of blasts on peripheral smear - suggests acute leukemia requiring bone marrow examination within 24-48 hours 1, 2
• Splenomegaly with leukocytosis - classic presentation of chronic myeloid leukemia (CML), which occurs in >50% of CML cases 5
• Constitutional symptoms (fever, weight loss >10%, drenching night sweats) combined with leukocytosis 1, 4
• Concurrent cytopenias or thrombocytosis on CBC 6

Lower-Risk Features Suggesting Reactive Leukocytosis

• Recent infection, surgery, trauma, or emotional stress - can double WBC within hours due to demargination 4, 6
• Medications including corticosteroids, lithium, or beta-agonists 6
• Smoking, obesity, or chronic inflammatory conditions 4

Specific Diagnostic Algorithm

If Peripheral Smear Shows Blasts or Dysplasia

• Bone marrow aspiration and biopsy urgently to quantify blast percentage and assess for acute myeloid leukemia (AML) - diagnosis requires >20% blasts 1, 2
• If AML confirmed with WBC >50,000/mcL and symptoms of leukostasis (headache, visual changes, dyspnea), emergency leukapheresis is indicated prior to induction chemotherapy 1, 2
• Standard induction chemotherapy consists of cytarabine 100-200 mg/m² continuous infusion × 7 days plus daunorubicin 60-90 mg/m² × 3 days for patients <60 years 3

If Splenomegaly Present with Left Shift and Basophilia

• Obtain BCR-ABL testing via RT-PCR or FISH from peripheral blood immediately - positive in nearly all CML cases 5
• Philadelphia chromosome cytogenetics from bone marrow if BCR-ABL positive to confirm CML 5
• Initiate hydroxyurea for rapid cytoreduction if symptomatic (dose typically 15-30 mg/kg/day) while awaiting confirmatory testing 3, 5
• Start imatinib 400 mg daily once CML diagnosis confirmed - this is first-line standard therapy 5

If Elevated Hemoglobin/Hematocrit with Leukocytosis

• Consider polycythemia vera - check JAK2 V617F mutation, which is present in >95% of PV cases 3
• Risk stratify based on age >60 years and prior thrombosis history - this patient is high-risk based on age alone 3
• Initiate phlebotomy to maintain hematocrit <45% in women 3
• Consider hydroxyurea for cytoreduction if symptomatic splenomegaly, progressive leukocytosis, or thrombocytosis develops 3

Critical Pitfalls to Avoid

• Never delay all-trans retinoic acid (ATRA) if acute promyelocytic leukemia (APL) is suspected based on presence of promyelocytes or Auer rods on smear - APL represents a medical emergency with high risk of fatal hemorrhage 1, 2
• Do not attribute leukocytosis solely to infection without peripheral smear review, as chronic leukemias are often discovered incidentally and patients may be asymptomatic 5, 6
• WBC >100,000/mcL represents a medical emergency due to risk of brain infarction and hemorrhage from leukostasis, requiring immediate leukapheresis 6

Management Based on Most Likely Scenarios

If Benign Reactive Cause Identified

• Treat underlying condition (infection, inflammation, discontinue offending medication) 4
• Repeat CBC in 2-4 weeks to document resolution 4
• If leukocytosis persists >4 weeks without clear cause, obtain hematology consultation even without other concerning features 4, 7

If No Clear Cause and Normal Peripheral Smear

• Hematology referral is still warranted given patient age of 62 years and persistent unexplained leukocytosis 4, 8
• Bone marrow examination may be indicated to exclude early myeloproliferative neoplasm, particularly given concurrent erythrocytosis 1

The combination of leukocytosis with elevated hemoglobin/hematocrit in a 62-year-old woman is concerning for a myeloproliferative neoplasm and should not be dismissed as reactive without thorough evaluation. 3, 5