NURS 245 - Chapter 24 (Disorders of Leukocytes & Lymphoid Tissue)

What is hematopoiesis?

The process of formation, development, and maturation of blood cells.

Where does hematopoiesis occur?

In the bone marrow, liver, and spleen.

What are the two types of stem cells derived from pluripotent stem cells?

Lymphoid stem cells and myeloid stem cells.

What do lymphoid stem cells develop into?

B cells, T cells, and NK cells (different types of lymphocytes).

What do myeloid stem cells differentiate into?

Erythrocytes, thrombocytes, neutrophils, eosinophils, basophils, and monocytes.

What are the cellular components of blood?

Erythrocytes, leukocytes, and thrombocytes.

What is the function of blood?

To transport oxygen, carbon dioxide, hormones, nutrients, and metabolic waste products, and to regulate body temperature and acid-base balance.

What is blood fractionation?

The process of separating blood into its component parts, usually performed by centrifuging the blood.

What is the definition of leukopenia?

A decrease in the number of white blood cells (leukocytes).

What is neutropenia?

A condition characterized by an abnormally low number of neutrophils.

What is neutrophilic leukocytosis?

An increase in the number of neutrophils in the blood.

What is lymphocytopenia?

A decrease in the number of lymphocytes in the blood.

What is lymphocytic leukocytosis?

An increase in the number of lymphocytes in the blood.

What are the main types of leukemias?

Acute lymphocytic leukemia (ALL), acute myelocytic leukemia (AML), chronic lymphocytic leukemia (CLL), and chronic myelocytic leukemia (CML).

What distinguishes Hodgkin's lymphomas from non-Hodgkin's lymphomas?

Hodgkin's lymphomas have Reed-Sternberg cells and typically present with specific clinical features, while non-Hodgkin's lymphomas do not.

What is multiple myeloma?

A type of cancer that forms in plasma cells, leading to bone marrow damage and various systemic effects.

What are hematopoietic growth factors?

Hormone-like regulatory molecules that aid in the survival, differentiation, and proliferation of progenitor cells.

What is the role of erythropoietin (EPO)?

EPO stimulates the production of red blood cells and is produced by the kidneys.

What is the role of thrombopoietin (TPO)?

TPO stimulates the production of platelets and is produced by the liver.

What does GM-CSF stand for?

Granulocyte-Monocyte Colony-Stimulating Factor.

What is hematology?

The study of blood and blood-related disorders, including their etiology, prevention, and treatment.

What is the approximate volume of blood in an adult human?

About 5 liters or 1.3 gallons.

What is the normal white blood cell count range?

4,500-10,500/µL

What are the main types of leukocytes that circulate in the blood?

Neutrophils, Eosinophils, Basophils, Monocytes, Lymphocytes (B cells, T cells, NK cells)

What percentage of the total leukocyte count do neutrophils represent?

60%-65%

What is the primary function of neutrophils?

To respond to bacterial and fungal infections by phagocytosis.

How do eosinophils stain and what is their primary function?

They stain bright red with acidic dye and primarily respond to parasitic infections.

What percentage of the total leukocyte count do eosinophils represent?

1%-3%

What is the primary role of basophils?

To respond to allergens by releasing heparin and histamine.

What percentage of the total leukocyte count do basophils represent?

0.3%-0.5%

What are the characteristics of monocytes?

They lack distinct cytoplasmic granules and have kidney-shaped nuclei.

What percentage of the total leukocyte count do monocytes represent?

3%-8%

What is the primary function of lymphocytes?

To respond to viral infections; B cells and T cells provide adaptive immunity, while NK cells provide innate immunity.

What percentage of the total leukocyte count do lymphocytes represent?

25%-30%

What is the role of B cells in the immune response?

B cells mature into plasma cells that produce antibodies and memory B cells that recognize returning pathogens.

What is the function of T cells in the immune system?

T cells help in cell-mediated immunity, with CD4+ helper T cells assisting in antibody production and CD8+ cytotoxic T cells targeting infected cells.

What are NK cells and their role in immunity?

Natural Killer (NK) cells recognize and kill cells infected with intracellular pathogens and destroy cancer cells.

What are the two categories of lymphoid tissues?

Central (primary) and peripheral (secondary) lymphoid tissues.

What is the function of bone marrow in lymphocyte development?

Bone marrow is the site of development of lymphocyte progenitor cells and maturation of immature B cells.

What is the primary function of the thymus?

The thymus is the site of maturation for immature T cells.

What are the primary functions of lymph nodes?

Lymph nodes filter lymph and activate lymphocytes in response to antigens.

What are common causes of neutropenia?

Inherited genetic disorders, chemotherapy, radiation therapy, and overwhelming infections.

What is the most common cause of neutrophilic leukocytosis?

Response to bacterial infections.

What is the definition of eosinophilia?

An elevated eosinophil count, often associated with allergic reactions or parasitic infections.

What does the suffix '-penia' refer to?

Absence or decreased count of a specific type of cell.

What does the suffix '-cytosis' refer to?

Elevated count of a specific type of cell.

What is invasive candidiasis?

A fungal infection caused by Candida albicans that can enter the bloodstream and affect other organs.

How does Candida albicans typically infect the body?

Through breaches in skin or mucosal barriers, such as surgery or catheter insertion.

What immune cells recognize PAMPs on fungal cell walls in invasive candidiasis?

Macrophages and NK cells

What do macrophages and NK cells produce upon recognizing PAMPs?

Pro-inflammatory cytokines such as IL-1, IL-6, and GM-CSF

What is the role of GM-CSF in the immune response to invasive candidiasis?

It stimulates the bone marrow to produce neutrophils.

What are common clinical manifestations of invasive candidiasis?

Non-specific signs such as fever, headache, muscle aches, abdominal pain, and fatigue.

What is the primary treatment for invasive candidiasis?

IV antifungal agents.

What defines lymphocytopenia?

An abnormally low lymphocyte count of less than 1,000/μL.

What is the normal range for lymphocyte count?

1,000-4,500/μL.

What are some causes of lymphocytopenia?

Inherited genetic disorders, chemotherapy, radiation therapy, prolonged malnutrition, and viral infections like HIV.

What is a potential consequence of lymphocytopenia?

Patients become prone to recurrent infections, usually viral.

How is lymphocytopenia typically diagnosed?

Often by chance during a complete blood count (CBC) for another reason.

What treatments are available for lymphocytopenia?

Antimicrobial agents and IV immunoglobulins.

What defines lymphocytic leukocytosis?

An abnormally high lymphocyte count of more than 4,500/μL.

What is the most common cause of lymphocytic leukocytosis?

An early response to a viral infection.

What is infectious mononucleosis commonly caused by?

The Epstein-Barr virus (EBV).

What are alternative names for infectious mononucleosis?

Kissing disease, mono, and glandular fever.

How does EBV evade immune destruction after initial infection?

By entering B cells in the MALT of the oropharynx and remaining dormant.

What are the hallmark clinical manifestations of infectious mononucleosis?

Fever, sore throat, headache, muscle aches, cervical lymphadenopathy, and splenomegaly.

What is the typical treatment for infectious mononucleosis?

Supportive care including bed rest, fluids, and analgesics.

What are leukemias?

Malignant neoplasms of hematopoietic stem cells that give rise to white blood cells.

How are leukemias classified?

Based on onset and progression (acute vs. chronic) and cell type of origin (lymphocytic vs. myelocytic).

What are the two main types of acute leukemias?

Acute lymphocytic leukemia (ALL) and acute myelocytic leukemia (AML).

What are common clinical manifestations of leukemias?

Fever, chills, loss of appetite, weight loss, splenomegaly, and bone pain.

What is leukostasis?

A medical emergency in acute leukemias characterized by greatly elevated circulating blast counts, increasing blood viscosity.

What are some known risk factors for developing leukemias?

Genetic factors (e.g., Down's syndrome), environmental factors (e.g., exposure to chemicals), and certain types of chemotherapy.

What is the Philadelphia chromosome associated with?

Chronic myelocytic leukemia (CML).

What can chronic exposure to certain chemicals lead to?

An increased risk of acute leukemias.

What is the significance of having risk factors for leukemia?

Having risk factors does not guarantee the development of the disease.

What are the primary methods for diagnosing lymphomas?

Leukocyte counts in blood, bone marrow biopsy for histological examination, and cytogenetic studies for chromosomal abnormalities.

What are the main treatment options for lymphomas?

Chemotherapy, radiation therapy, bone marrow transplantation, and antimicrobial agents to prevent and treat infections.

What are the two main categories of malignant lymphomas?

Hodgkin's lymphomas (HLs) and Non-Hodgkin's lymphomas (NHLs).

How do Hodgkin's lymphomas typically spread?

They originate in a single lymph node or a group of adjacent lymph nodes and spread in an orderly manner.

What is a key characteristic of Non-Hodgkin's lymphomas?

They can originate in multiple lymph nodes or groups of lymph nodes and spread in a random manner.

What age groups are most commonly affected by Hodgkin's lymphomas?

Young adults (20-40 years) and older adults (≥55 years).

What are Reed-Sternberg cells?

Malignant transformed B cells that are characteristic of Hodgkin's lymphomas, appearing as large atypical lymphocytes.

What is a hallmark early finding in patients with Hodgkin's lymphomas?

Cervical lymphadenopathy, where lymph nodes are firm, rubbery, and enlarged.

What age group is more commonly affected by Non-Hodgkin's lymphomas?

Older adults (≥65 years).

What are some risk factors associated with Non-Hodgkin's lymphomas?

Infections (e.g., EBV, H. pylori), immunosuppression, and exposure to agricultural chemicals.

How do Non-Hodgkin's lymphomas typically present?

As painless enlargement of lymph nodes in the neck, axilla, or groin.

What are the two growth categories of Non-Hodgkin's lymphomas?

Aggressive NHLs and indolent NHLs.

What is Burkitt lymphoma?

A type of Non-Hodgkin's lymphoma of B cell origin that presents as a rapidly growing tumor.

What is cutaneous T cell lymphoma?

A type of Non-Hodgkin's lymphoma of T cell origin that presents as persistent, itchy patches on the skin.

What characterizes Multiple Myeloma?

A malignancy of terminally differentiated B cells that produce large volumes of antibodies.

What age group is more commonly affected by Multiple Myeloma?

Older adults (≥70 years).

What is a common laboratory finding in Multiple Myeloma?

A serum protein electrophoresis reveals an M protein spike, usually IgG and IgA antibodies.

What are Bence-Jones proteins?

Light chain components of antibodies found in the urine of patients with Multiple Myeloma.

What are some clinical characteristics of Multiple Myeloma?

High levels of abnormal antibodies, increased blood viscosity, and bone resorption leading to hypercalcemia.

What are common signs and symptoms of Multiple Myeloma?

Fatigue, dull ache in the bones, and fractures.

What imaging finding is associated with Multiple Myeloma?

X-rays may show multiple 'punched-out' osteolytic lesions.