Hematologic and Oncologic Disorders
The hematologic and oncologic domain tests anemia, coagulation disorders, venous thromboembolism, neutropenic fever, transfusion, and cancer screening, with attention to urgent complications.
Core rules
- Microcytic anemia with low ferritin indicates iron deficiency. Find the source, especially gastrointestinal blood loss in adults. Ferritin is an acute-phase reactant and can be normal in inflammation.
- Pancytopenia with blasts suggests acute leukemia and requires urgent hematology evaluation. Neutropenic fever is a medical emergency: cultures and broad-spectrum antibiotics within 60 minutes.
- Venous thromboembolism: start anticoagulation when suspicion is high, before imaging confirmation, unless bleeding risk is prohibitive. Duration depends on provoked versus unprovoked status and cancer.
- Tumor lysis syndrome: hyperkalemia, hyperphosphatemia, hyperuricemia, and hypocalcemia after cytotoxic therapy. Treat with fluids, urate-lowering therapy, and electrolyte monitoring.
Worked example
A 42-year-old woman has fatigue, hemoglobin 9 g/dL, MCV 72 fL, and ferritin 8 ng/mL. This is iron deficiency anemia. Start oral iron and evaluate for gastrointestinal blood loss, even without visible bleeding. Do not assume anemia of chronic disease when ferritin is low.
Traps
- Transfusing stable iron deficiency instead of identifying the source.
- Delaying antibiotics in neutropenic fever.
- Missing spinal cord compression in cancer with new back pain and neurologic signs.
- Using ferritin alone during inflammation without considering transferrin saturation.