1. LEUKOPENIA Abnormally LOW WBC

2. NEUTROPENIA, AGRANULOCYTOSIS

3. NEUTROPENIA Reduction in the number of granulocytes in PBS (peripheral blood smear) < 2000/uL Mild 1000-2000/uL Moderate 500-1000/uL Severe (agranulocytosis) <500/uL DEFINITION:

4. AGRANULOCYTOSIS Marked reduction in neutrophil count Disappearance of neutrophil precursors in the bone marrow Absence or less than 500/uL of pmns

5. PATHOGENESIS: 1. INEFFECTIVE GRANULOPOIESIS 2. ACCELERATED REMOVAL OR DESTRUCTION OF NEUTROPHILS

6. Multipotent Progenitors Commited Precursors Late Precurosors Mature Form

7. INEFFECTIVE GRANULOPOIESIS Suppression of hematopoietic stem cells Aplastic anemia Infiltrative d/o Suppression of committed granulocytic precursors Alkylating drugs – generalized effect Idiosyncratic reaction – Chloramphenicol

8. Defective precursor cells susceptible to death while in BM Megaloblastic anemia Genetic defect  impaired granulocytic differentiation : Kostmann syndrome INEFFECTIVE GRANULOPOIESIS

9. Immune mediated Idiopathic Autoimmune Drugs Splenic sequestration 20 to enlargement of spleen Increased peripheral utilization Overwhelming infection ACCELERATED REMOVAL/DESTRUCTION

10. Most common cause is DRUG TOXICITY Alkylating drugs/ Anti-metabolites Generalized suppresion of BM  Agranulocytosis Predictable Dose related Chlorpromazine/ Phenothiaxines Toxinc effect on granulocytic precursors in BM Thiouracil/Sulfonamides/ Aminopyrine Antobody mediated destruction of mature neutrophils Autoantibodies against neutrophil specific antigens Suppression of marrow granulocytic progenitors by products of neoplastic cell Agranulocytosis:

11. S/S Related to infection Malaise, chills, fever Marked weakness & fatigue Death in severe agranulocytosis Neutrophil count < 500/mm3 CLINICAL COURSE:

12. Broad spectrum antibiotic G-CSF , a growth factor that stimulates production of granulocytes from BM Given following chemotx Withdrawing or tapering dose of drug Treatment:

18. CAUSES:

19. CAUSES:

20. ACUTE NONSPECIFIC LYMPHADENITIS

21. Reactive changes to: Microbe , Cell debris, Foreign matter Localized – Regional LN Generalized Lymphadenopathy Systemic Viral infection – Children Bacteremia Prominence of Lymphoid Follicles with Large germinal center, Debris, Macrophages, Necrosis, Suppuration Features:

22. Enlarged Tender to touch Fluctuant if (+) abscess Draining sinuses to skin Suppurative necrosis Clincal Presentation:

23. CHRONIC NONSPECIFIC LYMPHADENITIS MORPHOLOGIC TYPES

24. Activation of Humoral response Rheumatoid arthritis Early stage of HIV Must be differentiated from Follicular Lymphoma Germinal center B-cells are (+) for BCL2 stain FOLLICULAR HYPERPLASIA

25. Morphology

26. Trigger the Cellular Immune responses Reactive changes in T cell region of LN PARACORTICAL AREA EXPANSION EFFACED THR FOLLICLES Drugs – Dilantin Acute viral infxn IM Viral Vaccine PARACORTICAL LYMPHOID HYPERPLASIA

27. PARACORTICAL LYMPHOID HYPERPLASIA

28. Distention of lymphatic sinusoids Non-specific Particularly prominent in LN draining cancers Represent host immune reaction to cancer Sinus Histiocytosis

29. Sinus Histiocytosis