🩸 Leukocytosis · Neutrophilia · Lymphocytosis · Leukemia · Infection · Stress

Schwartz Clinical Handbook — Chapter 48 · Differential (neutrophils, lymphocytes) · Leukemoid reaction · ALL · AML · CML · Pertussis · Kawasaki

Select WBC count, differential (neutrophils, lymphocytes, bands, blasts), fever, lymphadenopathy, hepatosplenomegaly, petechiae, and age → differentiate reactive neutrophilia (infection, stress, steroids) from lymphocytosis (pertussis, viral) from leukemia (blasts, cytopenias) and leukemoid reaction.
⚠️ Red flags: blasts on smear, pancytopenia, hepatosplenomegaly, bone pain → urgent oncology referral.

📋 Step 1 — WBC count, differential & clinical signs
📌 Diagnostic impressions
📖 Schwartz Ch 48

Select total WBC count, differential (neutrophils, lymphocytes, bands, blasts), fever, lymphadenopathy, hepatosplenomegaly, petechiae, and age → differentiate reactive neutrophilia (bacterial infection, steroids, stress) from lymphocytosis (pertussis, viral, EBV) from leukemia (ALL, AML, CML) or leukemoid reaction.

✔️ Neutrophilia: bacterial infection, Kawasaki, tissue necrosis, steroids.
✔️ Lymphocytosis: pertussis (marked), EBV (atypical lymphocytes), viral.
✔️ Leukemia: blasts, cytopenias (anemia, thrombocytopenia), organomegaly.
✔️ Leukemoid reaction: WBC >50k, left shift, no blasts.
📘 Schwartz pearls (Chapter 48)
• ANC = WBC × (%segs + %bands). Toxic granulation, Döhle bodies suggest infection.
• Leukemoid reaction (WBC >50k) can mimic CML — LAP score, BCR‑ABL.
• ALL: most common childhood leukemia, age 2‑5y, blasts, cytopenias.
• CML: splenomegaly, leukocytosis (all stages), Philadelphia chromosome.