Hoja de repaso: Blood Disorders and Hematology Essentials

📋 Course Outline

1. Blood Components
2. Anemia Types
3. Leukemia Variants
4. Hemophilia Types
5. Sickle Cell Disease
6. Thalassemia
7. Coagulation Cascade
8. Von Willebrand Disease
9. Blood Transfusion Indications
10. Blood Product Types
11. Blood Typing Systems
12. Transfusion Risks

📖 1. Blood Components

🔑 Key Concepts & Definitions

• Red Blood Cells (Erythrocytes): Biconcave, disc-shaped cells responsible for oxygen transport via hemoglobin; lifespan approximately 120 days.
• White Blood Cells (Leukocytes): Immune cells defending against infections; includes neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
• Platelets (Thrombocytes): Small cell fragments essential for blood clotting; lifespan about 7-10 days.
• Plasma: The liquid component of blood, comprising water, electrolytes, proteins (albumin, globulins, fibrinogen), hormones, and waste products.

📝 Essential Points

• Blood is composed of cells (RBCs, WBCs, platelets) suspended in plasma.
• Red blood cells contain hemoglobin, which binds oxygen; their production (erythropoiesis) occurs in the bone marrow.
• White blood cells are vital for immune defense; their counts and types can indicate infections or hematologic disorders.
• Platelets facilitate clot formation by aggregating at injury sites and activating coagulation factors.
• Plasma maintains blood volume and pressure, transports nutrients, hormones, and waste; plasma proteins are crucial for osmotic balance and clotting.

💡 Key Takeaway

Blood components—red cells, white cells, platelets, and plasma—work together to sustain oxygen delivery, immune defense, and hemostasis, making their proper function vital for overall health.

📖 2. Anemia Types

🔑 Key Concepts & Definitions

• Anemia: A condition characterized by a decrease in red blood cell (RBC) count or hemoglobin concentration, impairing oxygen delivery to tissues.
• Microcytic Anemia: Anemia with small-sized RBCs, typically caused by iron deficiency or thalassemia.
• Macrocytic Anemia: Anemia with enlarged RBCs, often due to vitamin B12 or folate deficiency.
• Hemolytic Anemia: Anemia resulting from premature destruction of RBCs, leading to increased reticulocyte count and bilirubin.
• Aplastic Anemia: A marrow failure disorder where the bone marrow fails to produce sufficient blood cells, causing pancytopenia.
• Iron-Deficiency Anemia: The most common anemia, caused by inadequate iron intake, absorption, or chronic blood loss.

📝 Essential Points

• Anemia types are primarily classified based on RBC size (microcytic, macrocytic, normocytic) and cause.
• Microcytic anemia often involves iron deficiency or thalassemia; lab findings include low serum ferritin and microcytosis.
• Macrocytic anemia is linked to vitamin B12 or folate deficiency; features include hypersegmented neutrophils.
• Hemolytic anemia presents with elevated indirect bilirubin, reticulocytosis, and possible jaundice.
• Aplastic anemia involves hypocellular marrow with pancytopenia; may require bone marrow transplant.
• The underlying cause guides treatment: iron supplementation, vitamin therapy, immunosuppression, or transfusions.

💡 Key Takeaway

Anemia encompasses diverse conditions distinguished by RBC size and cause; accurate classification and understanding of underlying pathology are essential for effective management.

📖 3. Leukemia Variants

🔑 Key Concepts & Definitions

• Leukemia: A malignant proliferation of abnormal white blood cells originating in the bone marrow, leading to impaired hematopoiesis and infiltration of blood and tissues.

• Acute Leukemia: Rapidly progressing leukemia characterized by the accumulation of immature (blast) cells; requires prompt treatment. Subtypes include ALL (more common in children) and AML.

• Chronic Leukemia: Slower progression with proliferation of more differentiated (mature) white blood cells; includes CML and CLL.

• Acute Lymphoblastic Leukemia (ALL): Malignancy of lymphoid precursors, common in children; characterized by lymphoblast proliferation and infiltration.

• Chronic Myeloid Leukemia (CML): A myeloproliferative disorder marked by the Philadelphia chromosome (BCR-ABL fusion gene), leading to uncontrolled myeloid cell proliferation.

• Chronic Lymphocytic Leukemia (CLL): A lymphoid malignancy involving mature B lymphocytes; typically affects older adults and presents with lymphadenopathy and lymphocytosis.

📝 Essential Points

• Classification: Leukemias are classified based on the lineage (lymphoid or myeloid) and the course (acute or chronic). This classification guides diagnosis and treatment.

• Pathogenesis: Genetic mutations (e.g., translocations like t(9;22) in CML) lead to uncontrolled proliferation of abnormal cells, often with specific molecular markers.

• Clinical Features:

  • Anemia, bleeding, and infections due to marrow infiltration.
  • Splenomegaly and lymphadenopathy, especially in chronic types.
  • Bone pain and fatigue are common symptoms.

• Diagnosis:

  • Peripheral blood smear showing abnormal cells.
  • Bone marrow biopsy revealing blast percentage.
  • Cytogenetic and molecular studies for specific translocations (e.g., Philadelphia chromosome in CML).

• Treatment:

  • Chemotherapy, targeted therapy (e.g., tyrosine kinase inhibitors in CML), and sometimes stem cell transplantation.
  • Prognosis varies; CML now has a good prognosis with targeted therapy, while some acute leukemias require aggressive treatment.

💡 Key Takeaway

Leukemia encompasses diverse blood cancers distinguished by their cell lineage and disease course; understanding their genetic and clinical features is vital for diagnosis, prognosis, and targeted treatment strategies.

📖 4. Hemophilia Types

🔑 Key Concepts & Definitions

• Hemophilia A: An inherited bleeding disorder caused by deficiency or dysfunction of clotting factor VIII, leading to impaired blood clot formation.
• Hemophilia B: Also known as Christmas disease; caused by deficiency of clotting factor IX, resulting in similar bleeding tendencies as Hemophilia A.
• X-linked Recessive Inheritance: The pattern of inheritance for hemophilia, where the defective gene is located on the X chromosome; males are predominantly affected.
• Severity Classification: Based on the level of clotting factor activity:
  • Severe: <1% activity, frequent spontaneous bleeding.
  • Moderate: 1-5% activity, bleeding with minor injuries.
  • Mild: >5% activity, bleeding usually occurs after significant trauma or surgery.
• Bleeding Symptoms: Include spontaneous hemarthrosis, easy bruising, bleeding after trauma or surgery, and prolonged bleeding from cuts.
• Treatment: Replacement therapy with factor concentrates, prophylactic infusions, and supportive care.

📝 Essential Points

• Hemophilia is predominantly an X-linked recessive disorder, affecting mostly males; females are carriers.
• The severity of bleeding correlates with the residual activity of the deficient factor.
• Hemophilia A is more common than Hemophilia B, accounting for approximately 80-85% of cases.
• Clinical management involves regular factor replacement, especially in severe cases, to prevent bleeding episodes.
• Complications include joint damage from recurrent hemarthroses, inhibitor development (antibodies against infused factors), and bleeding into critical areas such as the brain.
• Diagnosis is confirmed through clotting factor assays measuring factor VIII and IX activity levels.

💡 Key Takeaway

Hemophilia types are inherited X-linked bleeding disorders characterized by deficiencies in clotting factors VIII or IX, with severity and clinical management directly related to residual factor activity; early diagnosis and replacement therapy are essential for preventing serious bleeding complications.

📖 5. Sickle Cell Disease

🔑 Key Concepts & Definitions

• Sickle Cell Disease (SCD): A hereditary hemoglobinopathy characterized by the production of abnormal hemoglobin S, leading to distorted, sickle-shaped red blood cells that are less flexible and more prone to hemolysis.

• Hemoglobin S (HbS): An abnormal form of hemoglobin resulting from a mutation in the beta-globin gene; causes red blood cells to sickle under low oxygen conditions.

• Autosomal Recessive Inheritance: A pattern where an individual must inherit two copies of the defective gene (one from each parent) to manifest the disease; carriers have one normal and one mutant gene.

• Vaso-occlusion: The blockage of blood flow caused by sickled cells adhering to the endothelium, leading to ischemia and pain crises.

• Hemolytic Anemia: A condition where sickled cells are prematurely destroyed, resulting in decreased red blood cell count and anemia.

• Sickling Crisis: An acute episode of pain and tissue ischemia caused by sickled cells obstructing blood flow, often triggered by dehydration, infection, or hypoxia.

📝 Essential Points

• Pathophysiology: The mutation in the beta-globin gene causes hemoglobin S formation. Under hypoxic conditions, HbS polymerizes, deforming red blood cells into a sickle shape, reducing their flexibility, lifespan (~120 days to ~10-20 days), and increasing hemolysis.

• Clinical Features: Chronic hemolytic anemia, episodic vaso-occlusive crises, jaundice, splenomegaly in early childhood, and increased risk of infections (especially encapsulated organisms).

• Diagnosis: Confirmed via hemoglobin electrophoresis, which shows predominant HbS in affected individuals. Newborn screening is standard in many countries.

• Complications: Stroke, acute chest syndrome, priapism, organ damage (kidneys, liver, heart), and increased susceptibility to infections.

• Management:

  • Hydroxyurea: Increases fetal hemoglobin (HbF) production, reducing sickling.
  • Pain management: During crises.
  • Preventive care: Vaccinations, penicillin prophylaxis, regular health monitoring.
  • Blood transfusions: For severe anemia or stroke prevention.
  • Bone marrow transplant: Potential cure in selected cases.

💡 Key Takeaway

Sickle Cell Disease is a genetic hemoglobin disorder causing sickled red blood cells that lead to hemolytic anemia and vaso-occlusion, resulting in painful crises and multi-organ damage; early diagnosis and comprehensive management are vital for improving patient outcomes.

📖 6. Thalassemia

🔑 Key Concepts & Definitions

• Thalassemia: An inherited hemoglobin disorder characterized by reduced or absent synthesis of one or more globin chains, leading to defective hemoglobin production and anemia.
• Alpha Thalassemia: A form caused by decreased or absent alpha-globin chain production due to gene deletions or mutations on chromosome 16.
• Beta Thalassemia: A form caused by defective beta-globin chain synthesis resulting from mutations on chromosome 11.
• Hemoglobin H Disease: A severe form of alpha thalassemia with significant hemolysis due to excess beta chains forming unstable hemoglobin H.
• Iron Overload: A common complication in thalassemia patients due to frequent transfusions, leading to damage in organs like the liver, heart, and endocrine glands.

📝 Essential Points

• Thalassemia is autosomal recessive; carriers are asymptomatic, but affected individuals exhibit varying degrees of anemia.
• Severity depends on the number of globin gene deletions or mutations; alpha thalassemia can range from silent carriers to hydrops fetalis, while beta thalassemia ranges from minor to major (Cooley's anemia).
• Beta Thalassemia Major (Cooley's anemia) presents in early childhood with severe anemia, growth retardation, hepatosplenomegaly, and skeletal deformities.
• Diagnosis: Hemoglobin electrophoresis shows abnormal hemoglobin patterns; peripheral blood smear reveals microcytic, hypochromic anemia with target cells.
• Management: Regular blood transfusions, iron chelation therapy, and in some cases, bone marrow transplantation.
• Complications: Iron overload, extramedullary hematopoiesis, splenomegaly, and increased risk of infections.

💡 Key Takeaway

Thalassemia is a hereditary hemoglobinopathy causing defective globin chain synthesis, leading to anemia and related complications; early diagnosis and management are crucial to improve patient outcomes and prevent iron overload.

📖 7. Coagulation Cascade

🔑 Key Concepts & Definitions

• Coagulation Cascade: A series of enzymatic reactions that lead to the formation of a stable blood clot, involving intrinsic, extrinsic, and common pathways.

• Intrinsic Pathway: Activation of clotting factors (XII, XI, IX, VIII) initiated by damage within the blood vessel or contact with exposed collagen; measured by activated partial thromboplastin time (aPTT).

• Extrinsic Pathway: Triggered by external trauma exposing tissue factor (Factor III), activating Factor VII; measured by prothrombin time (PT).

• Common Pathway: Convergence of intrinsic and extrinsic pathways at Factor X activation, leading to conversion of prothrombin (Factor II) to thrombin, and fibrinogen (Factor I) to fibrin, stabilizing the clot.

• Fibrin Clot Formation: The final step where fibrin strands form a mesh that stabilizes the platelet plug, completing hemostasis.

📝 Essential Points

• The cascade ensures rapid and localized clot formation in response to vascular injury, preventing excessive bleeding.

• The intrinsic pathway is activated by contact with negatively charged surfaces, while the extrinsic pathway is initiated by tissue injury releasing tissue factor.

• Both pathways activate Factor X, which, with the help of Factor V, converts prothrombin to thrombin.

• Thrombin plays a central role by converting fibrinogen into fibrin and activating other clotting factors, amplifying clot formation.

• The coagulation process is tightly regulated by anticoagulants like antithrombin III, protein C, and protein S to prevent abnormal clotting.

• Disorders in the cascade can lead to bleeding (e.g., hemophilia) or thrombosis (e.g., deep vein thrombosis).

💡 Key Takeaway

The coagulation cascade is a complex, highly regulated series of enzymatic steps that rapidly produce a fibrin clot to seal vascular injuries, with intrinsic and extrinsic pathways converging into a common pathway that culminates in stable clot formation.

📖 8. Von Willebrand Disease

🔑 Key Concepts & Definitions

• Von Willebrand Factor (vWF): A glycoprotein produced by endothelial cells and megakaryocytes that mediates platelet adhesion to damaged endothelium and stabilizes factor VIII in circulation.
• Von Willebrand Disease (VWD): An inherited bleeding disorder caused by quantitative or qualitative defects of vWF, leading to impaired platelet adhesion and clot formation.
• Type 1 VWD: Partial quantitative deficiency of vWF; the most common and mildest form.
• Type 2 VWD: Qualitative defect in vWF function; subtypes include 2A, 2B, 2M, and 2N, each with specific functional abnormalities.
• Type 3 VWD: Severe deficiency or absence of vWF; associated with significant bleeding symptoms.
• Bleeding Symptoms: Include mucocutaneous bleeding such as nosebleeds, gum bleeding, heavy menstrual bleeding, and easy bruising.

📝 Essential Points

• Pathophysiology: VWD impairs platelet adhesion and aggregation due to defective or deficient vWF, and also reduces factor VIII stability, leading to secondary deficiency.

• Inheritance: Autosomal dominant (most types) or recessive (Type 3).

• Diagnosis:

  • Screening Tests: Prolonged bleeding time, normal or mildly prolonged activated partial thromboplastin time (aPTT).
  • Specific Tests: Reduced vWF antigen levels, decreased ristocetin cofactor activity, and factor VIII activity.
  • VWF Multimer Analysis: Differentiates types 1, 2, and 3.

• Treatment:

  • Desmopressin (DDAVP): Releases stored vWF from endothelial cells; effective in Type 1 and some Type 2.
  • vWF Concentrates: Used in severe cases or Type 3.
  • Adjuncts: Antifibrinolytics (e.g., tranexamic acid) for mucosal bleeding.

• Clinical Relevance:

  • VWD is the most common inherited bleeding disorder.
  • Differentiating VWD from other bleeding disorders (e.g., hemophilia) is crucial for appropriate management.
  • Patients with VWD require careful planning before surgeries or dental procedures to prevent bleeding complications.

💡 Key Takeaway

Von Willebrand Disease is a prevalent inherited bleeding disorder caused by defective or deficient vWF, leading to impaired platelet adhesion and decreased factor VIII stability; diagnosis relies on specific assays, and management includes desmopressin and vWF concentrates to control bleeding.

📖 9. Blood Transfusion Indications

🔑 Key Concepts & Definitions

• Blood Transfusion: The process of transferring blood or blood components from a donor to a recipient to treat various medical conditions.
• Indication: A clinical condition or laboratory finding that warrants blood transfusion to improve patient outcomes.
• Severe Anemia: Hemoglobin levels typically below 7 g/dL, causing tissue hypoxia, often requiring transfusion.
• Acute Blood Loss: Rapid loss of blood volume due to trauma, surgery, or obstetric hemorrhage, necessitating transfusion to restore circulating volume.
• Coagulopathy: A disorder of blood clotting factors leading to bleeding; transfusions of plasma or specific clotting factors are indicated.
• Blood Product Compatibility: The matching of donor blood type with recipient to prevent transfusion reactions, based on ABO and Rh systems.

📝 Essential Points

• Blood transfusions are primarily indicated for severe anemia, significant blood loss, or bleeding disorders.
• Transfusion thresholds vary; generally, hemoglobin <7 g/dL in stable patients warrants transfusion, while higher thresholds may be used in symptomatic or high-risk patients.
• Types of blood products used include packed red blood cells (for anemia), platelets (for thrombocytopenia), and fresh frozen plasma (for coagulation factor deficiencies).
• Proper blood typing and crossmatching are critical to prevent hemolytic reactions.
• Transfusion carries risks such as allergic reactions, febrile reactions, hemolytic reactions, and TRALI; benefits must outweigh these risks.

💡 Key Takeaway

Blood transfusion is a vital intervention indicated in cases of severe anemia, significant blood loss, or clotting disorders, with careful matching and risk assessment to ensure safety and efficacy.

📖 10. Blood Product Types

🔑 Key Concepts & Definitions

• Whole Blood: Blood collected directly from a donor containing all components—red cells, plasma, platelets, and white cells—used primarily in massive transfusions.
• Packed Red Blood Cells (PRBCs): Concentrated red blood cells separated from plasma, used to treat anemia and blood loss; reduces volume load compared to whole blood.
• Platelet Concentrates: Blood product containing concentrated platelets, indicated for thrombocytopenia or platelet dysfunction.
• Fresh Frozen Plasma (FFP): Plasma separated and frozen within 8 hours of collection, rich in clotting factors, used in coagulopathy or bleeding disorders.
• Cryoprecipitate: A component of plasma rich in fibrinogen, factor VIII, von Willebrand factor, used in bleeding due to fibrinogen deficiency.
• Blood Typing & Crossmatching: Laboratory testing to ensure compatibility between donor blood and recipient, preventing transfusion reactions.

📝 Essential Points

• Blood products are selected based on the patient's specific deficiency or condition (e.g., anemia, thrombocytopenia, coagulopathy).
• PRBCs are the most commonly transfused blood component, especially in anemia management.
• Platelet transfusions are crucial in patients with severe thrombocytopenia or platelet dysfunction, such as in leukemia or chemotherapy.
• FFP is used to replenish clotting factors in conditions like liver failure, DIC, or warfarin overdose.
• Cryoprecipitate is administered for hypofibrinogenemia or certain bleeding disorders.
• Compatibility testing (ABO and Rh) is essential to prevent transfusion reactions; crossmatching confirms compatibility.
• Blood products have specific storage requirements and shelf lives; proper handling is critical.

💡 Key Takeaway

Blood product transfusions are tailored therapies that replace specific blood components to treat various hematological conditions, with compatibility testing being vital to ensure safety and prevent adverse reactions.

📖 11. Blood Typing Systems

🔑 Key Concepts & Definitions

• ABO Blood Group System: A classification based on the presence or absence of antigens A and B on red blood cell surfaces. It determines compatibility for transfusions and is the most clinically significant blood group system.

• Antigens: Molecules on the surface of red blood cells that trigger immune responses if incompatible blood is transfused. In ABO, these are A and B antigens.

• Antibodies (Isoagglutinins): Plasma proteins that recognize and attack foreign antigens. For example, individuals with blood type A have anti-B antibodies.

• Rh Factor (Rhesus Factor): A protein antigen (most commonly D antigen) on red blood cells. Its presence (Rh+) or absence (Rh-) influences transfusion compatibility and pregnancy management.

• Crossmatching: Laboratory testing to ensure donor blood is compatible with recipient blood, preventing transfusion reactions.

• Universal Donor/Recipient: Type O negative blood is considered the universal donor; AB positive is the universal recipient, due to their respective antigen and antibody profiles.

📝 Essential Points

• The ABO system is determined by the presence of A and B antigens; incompatibility can cause hemolytic transfusion reactions.
• Blood type compatibility is crucial: Type O negative is compatible with all blood types (universal donor), while AB positive can receive from all types (universal recipient).
• Rh incompatibility, especially in pregnancy, can lead to hemolytic disease of the newborn (HDN); Rh-negative mothers should receive Rh immunoglobulin to prevent antibody formation.
• Crossmatching involves testing donor red cells with recipient serum to detect any incompatible antibodies before transfusion.
• Blood typing and crossmatching are mandatory steps to prevent transfusion reactions and ensure safe blood transfusion practices.

💡 Key Takeaway

Understanding blood typing systems, especially ABO and Rh, is vital for safe transfusion practices and preventing immune-mediated complications. Proper crossmatching ensures compatibility and minimizes transfusion-related risks.

📖 12. Transfusion Risks

🔑 Key Concepts & Definitions

• Alloimmunization: The immune response generated when a recipient develops antibodies against donor blood antigens, increasing risk of transfusion reactions in future transfusions.

• Hemolytic Transfusion Reaction (HTR): A serious complication caused by immune-mediated destruction of transfused red blood cells due to ABO or other incompatible blood group antigens.

• Transfusion-Related Acute Lung Injury (TRALI): A life-threatening reaction characterized by acute pulmonary edema and hypoxemia, often caused by donor anti-leukocyte antibodies reacting with recipient leukocytes.

• Infectious Transmission: The risk of transmitting infections such as HIV, hepatitis B and C, or syphilis through contaminated blood products if screening fails or is incomplete.

• Febrile Non-Hemolytic Reaction: A common, mild reaction caused by recipient antibodies to donor leukocytes, resulting in fever and chills without hemolysis.

• Iron Overload: A complication from multiple transfusions leading to excess iron deposition in organs, potentially causing damage; managed with chelation therapy.

📝 Essential Points

• Major Risks: Hemolytic reactions, infectious disease transmission, alloimmunization, TRALI, iron overload, allergic reactions.

• Prevention Strategies:

  • Rigorous blood typing and crossmatching to prevent incompatibility.
  • Donor screening and testing for infectious agents.
  • Leukoreduction (removal of white cells) to reduce febrile reactions and alloimmunization.
  • Use of pathogen-reduced or irradiated blood products in immunocompromised patients.

• Informed Consent & Monitoring:

  • Patients should be informed of potential risks.
  • Close monitoring during and after transfusion for early detection of reactions.

• Special Considerations:

  • Patients with multiple transfusions are at higher risk for alloimmunization and iron overload.
  • Use of washed or leukoreduced blood products can mitigate some risks.

💡 Key Takeaway

Transfusion risks include immune-mediated reactions, infection transmission, and iron overload; meticulous blood matching, screening, and monitoring are essential to minimize these dangers and ensure safe transfusion practices.

📊 Synthesis Tables

Feature	Anemia Types	Leukemia Variants
Classification	Microcytic, Macrocytic, Normocytic	Acute (blast proliferation) vs. Chronic (mature cells)
Common Causes	Iron deficiency, B12/folate deficiency, marrow failure	Genetic mutations, translocations, proliferation of abnormal cells
Key Laboratory Findings	Low serum ferritin (microcytic), hypersegmented neutrophils (macrocytic), reticulocytosis (hemolytic)	Blast percentage, cytogenetics (e.g., Philadelphia chromosome)
Typical Age Group	Iron deficiency (any age), B12 deficiency (elderly), marrow failure (adults)	ALL (children), CML/CLL (adults)
Main Treatment	Iron supplementation, vitamin therapy, marrow transplant	Chemotherapy, targeted therapy, stem cell transplant

Feature	Blood Components vs. Blood Disorders
Components	RBCs, WBCs, Platelets, Plasma
Function	Oxygen transport, immune defense, clotting
Disorders	Anemia, Leukemia, Hemophilia, Sickle Cell Disease, Thalassemia
Diagnostic Focus	Blood counts, smear, bone marrow, genetic tests
Treatment Approaches	Supplementation, transfusions, targeted therapies

⚠️ Common Pitfalls & Confusions

1. Confusing microcytic anemia caused by iron deficiency with thalassemia; both present with microcytosis but differ in serum ferritin and hemoglobin electrophoresis.
2. Mistaking leukemia types based solely on blood smear; need to consider clinical features and cytogenetics.
3. Overlooking the inheritance pattern of hemophilia; assuming it affects females equally.
4. Confusing sickle cell disease with other hemoglobinopathies; remember HbS presence is diagnostic.
5. Misinterpreting coagulation cascade steps; failing to distinguish intrinsic vs. extrinsic pathways.
6. Assuming all bleeding disorders are inherited; some are acquired (e.g., vitamin K deficiency affecting multiple factors).
7. Overgeneralizing blood transfusion risks; not all transfusions carry the same risk profile.

✅ Exam Checklist

• Define the main components of blood and their functions.
• Differentiate between types of anemia based on RBC size and causes.
• List common features and genetic basis of sickle cell disease.
• Describe the pathophysiology and inheritance of hemophilia A and B.
• Identify leukemia variants by cell lineage and clinical presentation.
• Explain the coagulation cascade, including intrinsic and extrinsic pathways.
• Describe Von Willebrand disease and its effect on clotting.
• List indications for blood transfusion and types of blood products used.
• Understand blood typing systems (ABO, Rh) and their importance.
• Recognize common risks associated with blood transfusions.
• Summarize the classification and clinical features of thalassemia.
• Outline the treatment strategies for leukemia and hemophilia.
• Recall the laboratory findings characteristic of different anemia types.