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PA18.1-2 | Welcome to Reactive Leucocytosis, Leucopenia & Lymphocytosis
Learning Objectives
- State the normal ranges for total WBC count and the five-part differential.
- Enumerate the major causes of neutrophilia, neutropenia, lymphocytosis, eosinophilia, monocytosis, and basophilia.
- Describe the morphological changes of reactive neutrophilia — left shift, toxic granulation, Döhle bodies.
- Distinguish a leukaemoid reaction from chronic myeloid leukaemia using LAP score, basophilia, and clinical context.
- Recognise the atypical lymphocytes of infectious mononucleosis and distinguish reactive from neoplastic lymphocytosis.
- Apply the NAACP mnemonic to the causes of eosinophilia.
- Explain the concept of a leukoerythroblastic picture and its significance.
INSTRUCTIONS
Reactive changes in white-cell counts are the most common haematological finding in everyday clinical practice — virtually every ward patient will have a full blood count. This module equips you to read the differential count systematically, recognise the morphological clues of reaction versus malignancy, and avoid the trap of labelling a leukaemoid reaction as leukaemia. The analytical habits you build here are the scaffolding for SDL 2 and SDL 3, which take you into myeloid and lymphoid malignancies.
References
- Robbins & Kumar: Basic Pathology, 11th ed, Ch 11 (Red Cell and Bleeding Disorders) and Ch 12 (White Cell Disorders) (textbook)
- Harsh Mohan: Textbook of Pathology, 8th ed, Ch 12 (Disorders of WBCs) (textbook)
- Dacie & Lewis: Practical Haematology, 12th ed, Ch 5 (Blood Cell Morphology) (textbook)
Version 2.0 | NMC CBUC 2024