Hematologic System and Homeostasis

• The hematological system is composed of blood components and organs
• The hematological system plays a vital role in maintaining homeostasis on the entire body
• The hematological system affects multiple cellular activities, including:
  • Oxygen transport and delivery
  • Hemostasis
  • Immune response

Anatomy & Physiology

• Blood is a suspension of erythrocytes, leukocytes, platelets, and other particulate material in an aqueous colloid solution
• Blood provides a medium for exchange between fixed cells in the body and the external environment
  • Nutrients (i.e., oxygen and glucose) are carried to each cell
  • Cellular waste (i.e., carbon dioxide and nitrogen) are removed
• Other essential functions of blood include:
  • Regulation of PH
  • Regulation of temperature
  • Regulation of cellular water
  • Prevention of fluid loss through coagulation
  • Protection against toxins and foreign microbes

Blood Components

• Plasma
• Blood Cells:
  • Erythrocytes (RBC)
  • Leukocytes (WBC)
    • Neutrophils
    • Eosinophils
    • Basophils
    • Monocytes
    • Lymphocytes
    • Plasma cells
  • Thrombocytes (platelets)

Plasma

• Plasma is the liquid component of blood
• Plasma makes up about 55% of blood volume
• Plasma is essential for transporting nutrients, hormones, waste products, and blood cells throughout the body

Composition of Plasma

• Plasma is about 90% water, which helps maintain hydration and transport substances
• The remaining 10% of plasma consists of dissolved substances, including:
  • Proteins (albumin, fibrinogen, immunoglobulins)
    • Albumin: The primary protein found in Plasma; it maintains blood volume, regulates pH, regulates electrolyte balances and transportation of substances
  • Electrolytes (sodium, potassium, calcium)
  • Nutrients (glucose, amino acids, fatty acids)
  • Waste products (carbon dioxide, urea, creatinine)
  • Hormones (insulin, growth hormones)
  • Gases (oxygen and carbon dioxide)

Key Functions of Plasma

• Transport: Transports blood cells throughout the circulatory system.
  • Carries nutrients absorbed from the digestive system to tissues/organs
  • Transports waste products (e.g., urea, carbon dioxide) to organs (e.g., kidneys, lungs) for excretion
  • Distributes hormones produced by glands to target organs, coordinating bodily functions
• Clotting
  • Contains fibrinogen and other clotting factors essential for blood clotting
  • When a vessel is injured, fibrinogen is converted into fibrin, forming a clot to prevent excessive bleeding
• Immune Function
  • Contains antibodies (immunoglobulins), proteins that help the body fight infections
  • Identifies and neutralizes bacteria, viruses, and other pathogens
  • Transports WBCs to areas of infection or injury
• Maintaining Blood Volume
  • Plasma proteins, especially albumin, help maintain oncotic pressure, regulating the movement of fluids between blood and tissues
  • Helps prevent edema, ensuring proper circulation of fluids
• Acid-Base Balance
  • Plays a role in maintaining the body's pH balance (7.35-7.45)
  • Carries buffering agents, helping neutralize excess acids or bases
  • Ensures proper cellular function
• Temperature Regulation
  • The water content allows it to act as a heat conductor
  • Distributes heat throughout the body, helping regulate body temperature

Clinical Significance for Nursing

• Fluid and Electrolyte Imbalance: It's critical to understand the fluid and electrolyte balance.
  • Monitor plasma levels of electrolytes (e.g., sodium and potassium) during IV therapy, dehydration, or electrolyte disorders
• Blood Transfusions
  • Plasma is often separated from blood during transfusions
  • Fresh Frozen Plasma (FFP) is used in patients with clotting disorders, liver disease, or massive blood loss to replace clotting factors
• Plasma Volume Expanders
  • In cases of hypovolemia (low blood volume) due to trauma or surgery, plasma expanders (like albumin or synthetic colloids) can be administered to restore blood volume and maintain it
• Plasma Donation
  • Plasma can be donated separately from blood through a process called plasmapheresis
  • It is often used for patients requiring specific components like clotting factors or immune proteins

Hypoalbuminemia

• Decreased Oncotic Pressure:
  • Albumin helps retain water in blood vessels by exerting oncotic pressure; when albumin levels drop, pressure decreases
  • Fluid leaks out of blood vessels into surrounding tissues, resulting in edema
• Fluid Shift to Interstitial Space:
  • Without sufficient oncotic pressure, water moves from the intravascular space into the interstitial space
  • It can lead to fluid accumulation in tissues, especially in legs, arms, and abdomen
• Intravascular Dehydration:
  • As more fluid moves into tissues, blood volume decreases, leading to hypotension
  • Reduced perfusion to vital organs can cause symptoms like dizziness, fatigue, or fainting
• Compensation Mechanisms:
  • The body attempts to compensate by activating mechanisms like the renin-angiotensin-aldosterone system (RAAS) and releasing antidiuretic hormone (ADH). RAAS and ADH retain sodium and water to increase blood volume
  • This compensation may worsen fluid retention and exacerbate edema without resolving the underlying problem

Erythrocytes

• Most abundant type of blood cell
• Adults have approximately 5 million RBCs per microliter of blood
• They play a vital role by transporting oxygen from the lungs to tissues and returning carbon dioxide from tissues to the lungs for exhalation

Key Characteristics of Erythrocytes

• Shape: unique disc-like biconcave shape, which increases the cell's surface area
  • This shape allows for more efficient gas exchange and gives RBCs flexibility, enabling them to travel through capillaries
• Lack of Nucleus: Mature erythrocytes in humans do not have a nucleus or other organelles
  • This allows more space for hemoglobin, the protein that binds to oxygen and carbon dioxide
  • Erythrocytes cannot repair themselves and have a lifespan of about 120 days
• Hemoglobin: Iron-containing protein that gives erythrocytes their red color and allows them to carry oxygen
  • Each Hg molecule can carry up to four oxygen molecules
  • Oxygen binds to the iron in hemoglobin, forming oxyhemoglobin in lungs
  • In tissues where oxygen is lower, Hg releases oxygen and picks up carbon dioxide, forming carbaminohemoglobin, which is carried back to the lungs for exhalation
• Erythropoiesis: Erythrocytes are produced in bone marrow through a process called erythropoiesis
  • Erythropoiesis is stimulated by erythropoietin (EPO), a hormone released by the kidneys in response to low oxygen levels in blood (hypoxia)
  • Erythropoiesis is tightly regulated to maintain an appropriate number of RBCs, ensuring enough oxygen is transported while preventing blood from becoming too viscous
• Lifespan and Destruction: After about 120 days, aged erythrocytes are removed from circulation
  • They are removed by the spleen and liver through hemolysis
  • Iron from hemoglobin is recycled, while other components of RBC are broken down and excreted

Lab Values Associated with RBC

• Hematocrit: A proportion of blood that consists of packed RBCs expressed as a percentage of volume
  • Women 37%-47%
  • Men 40%-54%
• RBC Count
  • Women is 4.2-5.4 million/mm3
  • Men is 4.6-6.2 million/mm3
• Hemoglobin (Hgb)
  • Women is 120-160 (12-16 g/dl)
  • Men is 140-180 (14-18 g/dl)
• Platelets: 150,000-400,000ul
  • Aid in hemostasis and maintenance of vascular integrity
• MCV (mean corpuscular volume): Average volume of RBCs in a sample
• MChgb content: Average Hgb content of a RBC sample
• MChgb concentration: Average Hgb content in 100ml of blood

Hemoglobin

• There are 300 different types of genetically determined hemoglobin (hgb)
• Primary vehicle of O2 & CO2 transport
• Buffers PH by binding to hydrogen ions
• Types of Hemoglobin:
  • Hemoglobin A (HbA): The most common form in adults
  • Hemoglobin F (HbF): It is predominant in fetuses and infants
    • It has a higher affinity for oxygen to facilitate oxygen transfer from the mother's blood
  • Hemoglobin S (HbS): A variant is found in individuals with sickle cell disease
    • It causes red blood cells to take on a sickle shape under low oxygen conditions, leading to complications
  • Hemoglobin A1: Normal range is 12.1-16.3 g/dL, 90% of total hemoglobin
    • Low levels indicate anemia or blood loss
  • Hemoglobin A2: Normal range is 1.5%-3.5% of total hemoglobin
    • High levels may indicate thalassemia
  • Hemoglobin F: Normal range in neonates is 50-90%, and in adults is 0%-1%
    • High levels in neonates, and long term elevations may indicate a thalassemia
  • Hemoglobin S: Presence is abnormal and indicates sickle cell disease
  • Plasma: Normal range is 5mg/dL
    • High levels may indicate a hemolytic anemia

HgB A1C

• Measures the average blood glucose levels over the past 2 to 3 months
• Commonly used to diagnose and manage diabetes
• Reflects how blood sugar levels have been controlled over time
  • Normal: Less than 5.7%
  • Prediabetes: 5.7% to 6.4%
  • Diabetes: 6.5% or higher

Clinical Considerations

• Anemia: A condition where hemoglobin levels are lower than normal, reducing oxygen-carrying capacity of blood
  • Common causes include iron deficiency, chronic disease, hemolysis, and blood loss
  • Symptoms include fatigue, weakness, shortness of breath, and pallor
• Sickle Cell Disease: Hemoglobin S is a mutated form of hemoglobin, causing red blood cells to become rigid and sickle-shaped under low oxygen conditions Leads to blockages in small blood vessels, pain crises, and complications such as stroke and organ damage
• Thalassemia: A genetic disorder that results in reduced production of either the alpha or beta globin chains of hemoglobin
  • It leads to ineffective erythropoiesis and hemolytic anemia
• Hemoglobinopathies: Conditions like Hemoglobin C or E variants can cause different degrees of anemia, hemolysis, or mild disease, depending on the genetic mutation
• Polycythemia: This condition is characterized by the overproduction of red blood cells and, consequently, hemoglobin -It increases the viscosity of blood and the risk of clotting or stroke

Platelets/Thrombocytes

• Small, disc-shaped cell fragments in the blood
• Plays a crucial role in blood clotting (hemostasis)
• Derived from large bone marrow cells called megakaryocytes
• Vital for preventing bleeding by forming blood clots at sites of vessel injury

Key Functions of Platelets

• Hemostasis: When a blood vessel is injured, platelets:
  • Adheres to the damaged site by binding to the exposed to collagen of the vessel wall
  • Activates and release chemical signals (e.g., ADP, thromboxane A2) that recruit more platelets to the site of injury
  • Aggregates by sticking together to form a platelet plug
  • Help stabilize the platelet plug by facilitating the coagulation cascade, leading to the formation of a fibrin clot that seals the wound
• Wound Healing: After clot formation, platelets release growth factors like platelet-derived growth factor (PDGF), which is essential for tissue repair and healing

Platelet Activation and the Clotting Process

• Vascular Injury: When endothelium (inner lining of blood vessel) is damaged, platelets are exposed to substances like collagen and von Willebrand factor (vWF), which trigger their activation
• Platelet Adhesion: Platelets adhere to exposed collagen at the injury site using glycoprotein receptors on their surface (e.g., GPIb-IX-V complex binds to vWF)
• Platelet Activation: Once adhered, platelets change shape and release granules
• Platelet Aggregation: Activated platelets use fibrinogen as a bridge to link together via glycoprotein IIb/IIIa receptors, forming a temporary platelet plug
• Clot Formation: Clotting cascade is initiated, leading to conversion of fibrinogen into fibrin, which reinforces platelet plug and forms a stable blood clot

Platelet Disorders

• Thrombocytopenia:
  • Can result from bone marrow disorders, autoimmune diseases, medications, infections, or excessive platelet destruction
  • Symptoms include easy bruising, prolonged bleeding from cuts, petechiae, nosebleeds, and gum bleeding
• Thrombocytosis:
  • The causes are primary (due to bone marrow disorders) or secondary (reactive) to conditions like inflammation, infection, or after surgery
  • May be asymptomatic, but an increased risk of blood clots or bleeding due to abnormal platelet function
• Platelet Dysfunction
  • Can occur due to inherited disorders like Glanzmann thrombasthenia or Bernard-Soulier syndrome
  • Acquired dysfunction can result from medications like aspirin or clopidogrel

Thrombocytopenia Case Study

• A 56-year-old woman, Mrs. J, is 2 days post op radical mastectomy with a history of breast cancer and currently undergoing chemotherapy
• Nurse notes patient is bruising, has petechiae, and a nosebleed ongoing for an hour
• Platelet count is 18,000/μL
• Initial "red flag" is the low platelet count
• Further Assessment: Assess for additional signs of bleeding, such as hematuria, melena, or gingival bleeding
  • Neurological assessment to rule out intracranial bleeding
  • Check vital signs for signs of hypovolemia due to blood loss
• Diagnostics
  • Bone marrow biopsy (if needed) to assess function
  • Complete blood count (CBC) to evaluate other cell lines like red and white blood cells, and check for pancytopenia
  • Peripheral blood smear to identify any abnormal platelet morphology or destruction
  • Coagulation studies to rule out other coagulopathies
• Potential Causes of Thrombocytopenia
  • Chemotherapy-induced thrombocytopenia is the most likely cause
  • Bone marrow suppression
  • Other potential causes of thrombocytopenia include immune thrombocytopenic purpura (ITP), infection, or medications
• A likely treatment plan is a platelet transfusion given platelet count of 18,000/µL to raise platelet count and control the bleeding
  • Other local measures include pressure to the nostrils, administer topical hemostatic agents, pack the nose if necessary
  • Avoid invasive procedures like IM injections, central lines, or catheterizations as they can increase the risk of bleeding

Leukocytes/WBC

• The body's primary defense against infection
• 6 Types:
  • Neutrophils
  • Eosinophils
  • Basophils
  • Monocytes
  • Lymphocytes
  • Plasma Cells
    • Neutrophils attach and destroy bacteria and viruses through phagocytosis
    • Eosinophils attach to the surface of parasites, then release substances that kill the organism; detoxify inflammatory substances that occur in allergic reactions
    • Basophils prevent coagulation and speed fat removal from blood after a fatty meal
    • Monocytes consume bacteria, viruses, necrotic tissue, and other foreign material
    • Lymphocytes provide immunity against acquired infections; bases for antibody formation
    • Helper T Cells regulate immune functions; destroyed by AIDS
    • Cytotoxic T Cells are capable of direct attack on microorganisms
    • Suppressor T Cells protect from attack by person's own immune system by suppressing cytotoxic T-cell functions
    • Plasma Cells produce Y-globulin antibodies in response to specific antigens

Case Study: 6-Month Old Infant

• A nurse in a vaccine clinic is consulted about Lily, a 6-month-old infant, for her routine immunizations
• Her mother, Mrs. K, is concerned about the number of vaccines Lily is scheduled to receive; she asks how vaccines protect, and how immunizations activate Lily's immune system
• Vaccines introduce an antigen into the body by:
  • A weakened (attenuated) form of the virus or bacteria (e.g., measles, mumps, and rubella (MMR) vaccine)
  • An inactivated (killed) form of the pathogen (e.g., polio vaccine)
  • A component of the pathogen, such as a protein from the surface of the virus (e.g., hepatitis B or human papillomavirus (HPV) vaccine)
• Upon encountering the antigen, the body's immune system mounts a response by:
  • Activating antigen-presenting cells (APCs), such as dendritic cells or macrophages, which recognize the antigen and present it to T cells
  • T cell activation: Helper T cells recognize the antigen and stimulate B cells to produce antibodies
  • Cytotoxic T cells help destroy infected cells
  • B cell activation: B cells are stimulated to differentiate into plasma cells, which produce antibodies specific to the pathogen's antigens
  • Memory formation: Both memory B cells and memory T cells are produced
  • When Lily is exposed to the actual pathogen in the future, her immune system will recognize and quickly neutralize it, preventing illness
• The Immune Response: This prevents the disease

Disorders of RBC

• Iron Deficiency Anemia
  • The most common type of anemia
  • Caused by insufficient iron, which is needed for hemoglobin production
    • Commonly due to blood loss, dietary intake, or malabsorption
  • Symptoms include fatigue, weakness, pale skin, shortness of breath
    • Treat with iron supplementation
• Pernicious Anemia
  • Caused by a deficiency in vitamin B12 due to the body's inability to absorb it, due to a lack of intrinsic factor
    • Symptoms include neurological symptoms, fatigue, glossitis
    • Treat with B12 injection or high-dose oral supplementation
• Aplastic Anemia
  • Bone marrow fails to produce sufficient red blood cells, white blood cells, and platelets
  • Often due to autoimmune disorders, or toxic chemicals
    • Symptoms include fatigue, frequent infection, and easy bruising
    • Treat with bone marrow transplant or immunosuppressive therapy
• Hemolytic Anemia -Caused by sickle cell anemia -It results in destruction of red blood cells at a faster rate than they can be produced - Common causes are autoimmune diseases and inherited disorders like sickle cell anemia
  • Symptoms include Jaundice, fatigue, dark urine, or enlarged spleen
    • Treat with corticosteroids, immune suppression, or blood transfusions
• Sickle Cell Disease
  • Leads to blockages in blood vessels -Is an inherited disorder in which abnormal hemoglobin (HbS) causes red blood cells to become rigid and sickle-shaped
  • Symptoms include Painful crises, fatigue, Jaundice, and risk of infections
    • Treatment includes Pain management, and transplants
• Polycythemia Vera
  • A myeloproliferative disorder that often accompanies elevated white blood cells and Platelets
  • May cause an abnormal increase in RBCs
    • Symptoms include headaches, dizziness, and itching, it also increases the risk of thrombosis
  • Treat with Phlebotomy (blood removal)

WBC Disorders

• Leukopenia: A condition characterized by a low WBC count that may be caused by Bone marrow disorders and autoimmune diseases
• Leukocytosis: The cause is an elevated WBC Count
  • infections
  • Inflammatory conditions
  • Leukemia
• Leukemia: It is a group of cancers that affects blood and bone marrow characterized by abnormal proliferation of WBCs
  • Acute Lymphoblastic Leukemia (ALL), where rapid abnormal proliferation of immune lymphoblasts
  • Acute Myeloid Leukemia (AML): Rapid growth of abnormal myeloid cells
  • Chronic Lymphocytic Leukemia (CLL): Slow proliferation of abnormal lymphocytes
  • Chronic Myeloid Leukemia (CML): Progressive abnormalities in myeloid cells
• Lymphoma (lymphatic system cancer- abnormal lymphoma cells)
  • Hodgkin Lymphoma : Characterized by cells presence
  • Non-Hodgkin Lymphoma
• Multiple Myeloma: Type of WBC responsible for abnormal production of antibodies that affects plasma cells causing abnormal cells production
• Myelodysplastic Syndromes: Leads to a reduced number of blood products that are healthy

Acute and Chronic Leukemia

• Acute Leukemias: Include Acute Lymphoblastic Leukemia (ALL) and Acute Myeloid Leukemia (AML)
  • Acute Lymphoblastic Leukemia (ALL)
    • Characteristics Rapid growth of immature lymphoblasts
    • It is most common in children, but can also affect adults -Acute Myeloid Leukemia (AML)
    • Characteristics includes abnormal myeloid cells
    • It is more common in adults -Chronic Lymphocytic Leukemia (CLL)
  • It is more common in older patients with abnormal lymphocytes
• Chronic Myeloid Leukemia (CML)
  • it is genetic abnormality and causes abnormal chronic abnormal cells
  • it is very progressive

Leukemia Diagnosis and Treatment

• Common Symptoms include fatigue, weight loss, easy bruising, pale skin, and or painful joints
• Diagnosis typically involves: Blood Tests (Red Blood Cells, White Blood Cells and Platelets) -Bone Marrow: It used for examine marrow
  • Genetic: Look for abnormality
• Treatment options depend on the type and stage of leukemia -Chemotherapy Treatment : Target and kill cancer cells or stop their growth -Radiation Therapy :Target cancer cells in specific areas -Immunotherapy (using the body) -Stem Cell Treatment

Bleeding Disorders

• Conditions that affect the body's ability to control bleeding which can result to other problems
• Platelets disorders
• Hemophilia A: Caused by factor VIII
• Hemophilia B: Caused by factor IX
• Von Willebrand Disease: the body has difficulty with abnormal platelet adhesion Clotting too much results from Factor V Leide Mutation- genetic condition

Disseminated Intravascular Coagulation (DIC)

• Acquired Bleeding Disorders
• a deficiency of Vitamin k & liver damage
• Serious condition that can lead to bleeding due to consumption of clotting factors and platelets
• Major symptoms; Is the ability to have severe or major organ trauma where the body cant form clots for the damaged bleeding
• Treatments include platelets blood transfusions and medication that maintains blood pressure

Platelets Disorders

• Platelet transfusions are needed for treatments Causes for platelet disorders:
• Immune. Thrombocytopenia
• Thrombolytic Signs & Symptoms
• -Easy bruising or bleeding, bleeding gums, petechiae. Also prolonged bleeding from cuts or injuries.
• Treatment include lifestyle
• Bone Marrow (cell production) In conclusion lifestyle and treatment that depends on specific disorders is always the key for any diseases or syndromes