Non-Malignant Causes of Leukocytosis

Question 1

leukocytosis - clinical definition

Answer 1

*a total WBC count > 11K

Question 2

leukocytosis with neutrophilia

Answer 2

*WBC > 11K and absolute neutrophil count (ANC) > 7.7K
*note: ANC = # of PMNs and # of bands

Question 3

non-malignant causes of leukocytosis with neutrophilia

Answer 3

*infection
*stress (physical, emotional)
*smoking
*pregnancy
*post-exercise setting
*myocardial infarction
*generalized marrow stimulation (hemolysis, IDA)

Question 4

what are the 6 neutrophil storage pools?

Answer 4

*bone marrow:
-mitotic pool
-maturation pool
-storage pool

*peripheral blood:
-circulating pool
-marginated pool

*tissue pool

Question 5

what 2 chemicals can result in neutrophilia

Answer 5

1. G-CSF
2. GM-CSF

Question 6

leukocytosis with bandemia

Answer 6

*WBC > 11K and absolute band count > 0.7K
*“left shift”
*seen in acute bacterial infections
*should NOT see more immature cells on differential

Question 7

2 causes of lymphocytosis

Answer 7

*lymphocytosis is defined as absolute lymphocyte count > 4.8K
*MAIN CAUSE = VIRAL INFECTION (EBV, CMV, HIV, mumps, varicella, influenza, etc)

*non-viral causes:
-bordetella pertussis (whooping cough)
-bartonella henselae (cat scratch disease)
-toxoplasmosis
-babesiosis
*non-infectious causes:
-hypersensitivity reactions
-stress

Question 8

leukocytosis with monocytosis

Answer 8

*WBC > 11K and absolute monocyte count > 0.8K
*can be seen in acute bacterial infection, TB, or after GM-CSF administration
*uncommon

Question 9

3 types of eosinophilia

Answer 9

1. primary eosinophilia = malignancy
2. secondary eosinophilia = infectious (esp parasites or aspergillus); non-infection (allergic disorders, meds, etc)
3. idiopathic eosinophilia = unknown cause

Question 10

leukocytosis with basophilia

Answer 10

*causes include:
-hypersensitivity reactions
-ulcerative colitis
-rheumatoid arthritis
-hypothyroidism
-exogenous estrogen supplementation
-infections (viral, TB, helminths)

Question 11

pseudo-neutropenia

Answer 11

*increased percentage of neutrophils marginated against endothelial vessel walls
*still able to demarginate when needed
*no history of difficulty fighting infection

Question 12

infection as a cause of neutropenia

Answer 12

*particularly VIRAL infections can cause a transient neutropenia
*mononucleosis, hep B, and HIV can cause more protracted courses of neutropenia
*mechanisms include:
-marrow suppression
-upregulation of adhesion and migration due to complement and cytokine release

Question 13

medication-induced neutropenia

Answer 13

*over 100 drugs implicated
*mechanisms:
-immune mediated: metabolite of drug binds to neutrophil (or precursor) membrane and antibodies or T cells destroy the cell
-direct toxicity: neutrophils (or precursors) metabolize drug to toxic compound that results in cell death

Question 14

immune-mediated neutropenia

Answer 14

*anti-neutrophil antibodies (or antibodies to neutrophil precursors)
*can be seen with other immune-mediated disorders:
-autoimmune mediated hemolytic anemia
-immune mediated thrombocytopenia
-autoimmune disorders

Question 15

causes of lymphopenia

Answer 15

*decreased production:
-VIRAL INFECTIONS
-immunodeficiency diseases (AIDS, aplastic anemia)
*increased destruction
*congenital disorders