Leukopenia and Leukocytosis Flashcards
What is a normal white blood cell count?
5-10 K/uL
What is it called when there is a low WBC count (
Leukopenia
What is it called when there is a high WBC count (>10K)?
Leukocytosis
What are the 2 most common causes of neutropenia?
Drug toxicity
Severe infection
What is the mechanism of for neutropenia seen with drug toxicity?
Damage to stem cells→ decreased production of WBCs, especially neutrophils
What is the mechanism for neutropenia see with severe infections?
Increased number of neutrophils in the tissues leads to decreased circulating neutrophils
What is the treatment for neutropenia?
GM-CSF or G-CSF—boost granulocyte production
What are the 4 major causes of lymphopenia?
Immunodeficiency
High cortisol state
Autoimmune destruction
Whole body radiation
How does a high cortisol state induce lymphopenia?
Causes apoptosis of lymphocytes
What cells are highly sensitive to radiation and cause a specific type of leukopenia?
Lymphocytes—causing lymphopenia
What are the 3 major causes of neutrophilic leukocytosis?
Bacterial infection
Tissue necrosis
High cortisol state
How does a bacterial infection or tissue necrosis cause neutrophilic leukocytosis?
They induce the release of marginated pool and bone marrow neutrophils
What is a left shift of neutrophils seen with a bacterial infection or with tissue necrosis?
Immature neutrophils are released from the bone marrow causing the left shift
What characterizes the immature neutrophils that are released from the bone marrow during a bacterial infection or tissue necrosis?
Decreased Fc receptor CD 16
How does a high cortisol state cause neutrophilic leukocytosis?
A high cortisol state impairs leukocyte adhesion—causing a release of marginated pool of neutrophils
What are 2 causes of monocytosis?
Chronic inflammatory state
Malignancy
What are 3 causes of Eosinophilia?
Allergic rections
Parasitic infections
Hodgkin Lymphoma
What causes the eosinophilia seen with Hodgkin lymphoma?
Increased production of IL5
What disease is basophilia classically seen with?
Chronic myeloid leukemia
What are the 2 major causes of lymphocytic leukocytosis?
Viral infections
Bordetella pertussis infection
What is the mechanism for lymphocytic leukocytosis seen with a viral infection?
T lymphocytes undergo hyperplasia when the cells are infected with the virus
What causes lymphocytic leukocytosis when an individual is infected with Bordetella perussis?
The bacteria produces lymphocytosis-promoting factor. This blocks the circulating lymphocytes form leaving the blood and entering the lymph nodes.
What are the stem cells that differentiate to form WBCs?
Hematopoietic CD34+ Stem cells
What are the 2 arms of WBC development?
Myeloid stem cell
Lymphoid stem cell
What can lymphoid stem cells differentiate in to?
Plasma cells
CD8+ and CD4+ T cells
What can myeloid stem cells differentiate into?
RBCs Neutrophils Basophils Eosinophils Monocytes Megakaryocytes
What are the two viral infections that can cause infectious mononucleosis?
EBV
CMV
Infection by EBV causing lymphocytic leukocytosis comprised of reactive CD8+ T cells
Infectious mononucleosis
How is EBV transmitted?
Transmitted by saliva—called the kissing disease
Where are the primary sites of infection seen with EBV?
Oropharynx
Liver
B-cells
An EBV infection of the oropharynx results in ________.
Pharyngitis
What results when an EBV infection occurs in the liver?
Hepatitis with hepatomegaly and elevated liver enzymes
With infectious mononucleosis CD8+ T-cells cause generalized lymphadenopathy. What is the cause of this abnormal process?
T-cell hyperplasia in the lymph node paracortex
Where is the location of T-cell hyperplasia seen with infectious mononucleosis causing generalized lymphadenopathy?
Within the lymph node paracortex
What causes splenomegaly seen with infectious mononucleosis?
T-cell hyperplasia within the periarterial lymphatic sheath (PALS)
What test is used for screening of infectious mononucleosis?
Monospot test
What does the monospot test, used to screen for infectious mononucleosis, detect?
IgM antibodies that cross-react with a heterophile antibody (horse or sheep RBCs)
If a negative monospot test is obtain, what should one consider as the cause of infectious mononucleosis?
CMV
How is a definitive diagnosis made with infectious mononucleosis caused by EBV?
Serologic testing for the EBV viral capsid antigen
Why should patients who have been diagnosed with infectious mononucleosis within the last year avoid contact sports?
These patients are at an increased risk of splenic rupture
What can patients with infectious mononucleosis develop if exposed to ampicillin?
A rash
Dormancy of the EBV within B-cells can put patients at risk of developing what 2 complications?
Increased risk of recurrence of infectious mononucleosis
Increased risk of B-cell lymphoma
