Pediatric Hematology and Oncology
Core concepts
Understand anemia classification by MCV (microcytic, normocytic, macrocytic) and the workup of iron deficiency (most common cause; low ferritin, low MCV, elevated RDW). Know hemoglobinopathies: sickle cell disease (vaso-occlusive crisis, acute chest syndrome, splenic sequestration, stroke) and thalassemia (microcytic, target cells, elevated HbF/HbA2 patterns). Understand bleeding disorders: immune thrombocytopenia (isolated thrombocytopenia, petechiae, usually self-limited), hemophilia (prolonged PTT, joint bleeds), and von Willebrand disease. Know leukemia presentation (pallor, bruising, bone pain, hepatosplenomegaly, blasts) and lymphoma (painless lymphadenopathy, mediastinal mass). Recognize oncologic emergencies: tumor lysis syndrome, superior vena cava syndrome, spinal cord compression, and febrile neutropenia (urgent antibiotics).
Traps
- Missing iron deficiency because of a normal hemoglobin early in the course - check ferritin and RDW.
- Treating ITP with platelet transfusion unless there is life-threatening bleeding.
- Missing febrile neutropenia as an emergency requiring immediate antibiotics.
- Confusing sickle cell vaso-occlusive crisis with infection; both can coexist.
- Overlooking acute chest syndrome in a child with sickle cell and chest pain/fever.
Worked example / rule of thumb
A 6-year-old with sickle cell disease and fever 38.5°C: obtain cultures, start empiric antibiotics, and evaluate for acute chest syndrome (chest X-ray, oxygen saturation). Rule of thumb: fever in a child with sickle cell disease or neutropenia = urgent cultures and antibiotics; microcytic anemia in a child = iron deficiency until proven otherwise.