Alterations to haematological function Flashcards
What is Virchow’s triad?
Virchow’s triad is a set of three broad categories of factors that are thought to contribute to the formation of a thrombus, which is a blood clot.
What are the three categories of factors contributing to the formation of a blood clot? (As per Virchows triad)
Venous Stasis: This refers to the slowing or pooling of blood flow, which can occur in conditions where the blood doesn’t circulate normally. Reduced blood flow can increase the time blood components are in contact with the vessel walls, facilitating clot formation. Common situations include prolonged immobility (like during long flights or bed rest), and certain medical conditions that affect circulation.
Endothelial Injury: Damage to the endothelium, the inner lining of the blood vessels, can initiate clot formation. This damage can be due to various causes, such as surgery, trauma, infection, or inflammation. Endothelial injury exposes underlying tissues that provide a surface for clotting factors to gather and initiate the clotting process.
Hypercoagulability: This involves an increased tendency of the blood to clot, which can be due to genetic factors, certain medical conditions, or medications. Conditions that can lead to hypercoagulability include cancer, certain autoimmune disorders, pregnancy, and the use of hormone replacement therapy or oral contraceptives.
What is anaemia?
Anemia is a condition characterized by a decrease in the quantity or quality of red blood cells (RBCs) or a reduction in the amount of hemoglobin, an essential protein in red blood cells that carries oxygen to the body’s tissues. Because of this, anemia often leads to reduced oxygen flow to the body’s organs and tissues, resulting in symptoms like fatigue and weakness.
What are the different types of anaemia?
Anemia can be classified based on the underlying cause or the appearance of red blood cells under a microscope:
Iron Deficiency Anemia: The most common type, caused by a lack of iron, which is necessary for hemoglobin production. It can result from poor dietary intake, increased demand during pregnancy, or chronic blood loss (e.g., from ulcers or menstruation).
Vitamin Deficiency Anemia: Includes folate and vitamin B12 deficiency anemia, which affect red blood cell production. Folate-deficient diets, poor absorption, and increased needs during pregnancy can lead to folate deficiency. Vitamin B12 deficiency typically results from poor intake or malabsorption (as seen in conditions like pernicious anemia).
Anemia of Chronic Disease: Common in individuals with chronic infections, inflammatory diseases, or malignancies. These conditions can interfere with the production of red blood cells.
Aplastic Anemia: A rare condition where the bone marrow fails to produce sufficient numbers of blood cells. It can be caused by viral infections, certain medications, autoimmune diseases, and exposure to toxic chemicals.
Hemolytic Anemia: Occurs when red blood cells are destroyed faster than they can be produced. Causes include autoimmune diseases, certain genetic disorders (e.g., sickle cell anemia), infections, and exposure to certain chemicals or drugs.
Thalassemia: A genetic disorder inherited from parents where the body makes an abnormal form of hemoglobin, leading to excessive destruction of red blood cells and resulting in anemia.
What are the common symptoms of anaemia?
Common symptoms of anemia include:
Fatigue and Weakness: These are the most common symptoms of anemia. Due to the lack of sufficient oxygen reaching the body’s cells, the energy production in these cells is compromised, making a person feel tired and weak.
Pale or Yellowish Skin: Hemoglobin gives blood its red color, so low levels can cause the skin to look paler than usual. In cases of anemia caused by the destruction of red blood cells (hemolytic anemia), a person may also appear jaundiced (yellowing of the skin and eyes) due to the buildup of bilirubin, a byproduct of red blood cell breakdown.
Shortness of Breath: When hemoglobin levels are low, the body compensates by increasing respiratory rate to help increase oxygen intake, which can result in shortness of breath, especially during physical activity.
Dizziness or Lightheadedness: Insufficient oxygen supply to the brain can result in feelings of dizziness or lightheadedness, and in severe cases, it might lead to fainting.
Heart Palpitations: The heart may beat harder and faster to try to deliver enough oxygen to the body, leading to palpitations or an unusually rapid heartbeat.
Cold Hands and Feet: Oxygen is crucial for regulating temperature in the body. Inadequate oxygen supply can result in colder extremities.
Headaches: Limited oxygen delivery to the brain can also cause headaches.
How is anaemia treated?
Treatment for anaemia depends on the cause:
Iron Deficiency Anaemia:Treated with iron supplements and dietary changes.
Vitamin Deficiency Anaemia: Treated with folic acid and vitamin B12 supplements.
Anaemia of Chronic Disease: Addressing the underlying disease; sometimes medications that stimulate red blood cell production are used.
Aplastic Anaemia: Treatment can include blood transfusions, medications, and sometimes bone marrow transplants.
Hemolytic Anaemia: Treatment focuses on managing or preventing the destruction of red blood cells, and it may involve immunosuppressants.
Thalassemia: Treatment might include regular blood transfusions and chelation therapy to remove excess iron from the body.
Managing anaemia involves not only treating the symptoms but also addressing the underlying causes to prevent future problems. Regular follow-up with healthcare providers is essential for monitoring and maintaining good health.
Tell me about thrombocytopenia
Thrombocytopenia is a condition characterized by abnormally low levels of platelets, the cells that help blood clot. This can lead to easy bruising and excessive bleeding from cuts or injuries.
What are bleeding disorders?
Bleeding disorders are a group of conditions that result when the blood cannot clot properly. In normal clotting, platelets, a type of blood cell, stick together and form a plug at the site of an injured blood vessel. Proteins in the blood called clotting factors then interact to form a fibrin clot, essentially a mesh that holds the platelet plug in place and stops the bleeding. When clotting factors or platelets are missing or dysfunctional, bleeding can continue unchecked, which can lead to serious health issues.
What are some common types of bleeding disorders?
Hemophilia
Hemophilia A: Caused by a deficiency in clotting factor VIII.
Hemophilia B (Christmas disease): Caused by a deficiency in clotting factor IX.
Hemophilia is typically inherited and affects males more often due to its X-linked recessive pattern of inheritance. Individuals with hemophilia may experience spontaneous bleeding or prolonged bleeding after injury or surgery. Treatment often involves replacement therapy, where the missing clotting factors are provided through intravenous infusions.
Von Willebrand Disease (VWD)
The most common inherited bleeding disorder, VWD is caused by a deficiency or dysfunction of von Willebrand factor (VWF), a protein that helps platelets stick to the walls of blood vessels and binds to factor VIII, protecting it from degradation. VWD can affect both males and females. Treatment may include desmopressin (which can raise the levels of VWF and factor VIII) and VWF replacement therapies.
Platelet Function Disorders
Conditions like Glanzmann thrombasthenia and Bernard-Soulier syndrome fall into this category. These disorders are characterized by platelets that do not function correctly, even though the platelet count may be normal. Patients may experience frequent nosebleeds, gum bleeding, and excessive bleeding from small cuts.
Rare Factor Deficiencies
Deficiencies in other clotting factors (I, II, V, VII, X, XI, XII) are less common but can lead to bleeding tendencies. These disorders are usually inherited and can range in severity from mild to severe, depending on the level of factor activity.
Acquired Bleeding Disorders
Conditions like Disseminated Intravascular Coagulation (DIC), liver disease, and Vitamin K deficiency can lead to acquired bleeding disorders. These conditions affect the normal production or function of clotting factors and are not inherited. For example, liver disease can impair the production of clotting factors, and Vitamin K is essential for the synthesis of several clotting factors.
What are some symptoms of bleeding disorders?
Symptoms can vary widely depending on the specific disorder and severity but commonly include:
Easy or Excessive Bruising: People with bleeding disorders may bruise easily or excessively from minor bumps or injuries due to fragile blood vessels or poor clotting ability. The bruises might appear larger or more severe than expected for the injury.
Frequent Nosebleeds: Recurrent nosebleeds can occur when the blood vessels in the nose are fragile and the blood does not clot properly. These can be more common and harder to stop in individuals with bleeding disorders.
Prolonged Bleeding from Cuts: Bleeding from small cuts or injuries may take longer than usual to stop due to a delayed or weak clotting response.
Excessive Bleeding Following Surgery or Dental Work: People with bleeding disorders often experience significant bleeding after medical or dental procedures because the physical trauma can exceed the clotting ability of their blood.
Unexpected Heavy Menstrual Bleeding: Women with bleeding disorders may experience menorrhagia, or unusually heavy menstrual periods, which can be a sign of a clotting problem.
Blood in Urine or Stools: This may indicate bleeding within the kidneys, bladder, or gastrointestinal tract. It can manifest as pink to dark red urine or black, tarry, or bloody stools.
Joint Bleeds: In severe cases, such as in hemophilia, spontaneous bleeding can occur in the joints, leading to pain, swelling, and over time, damage to the joint tissues.
Fatigue: Chronic blood loss, even in small amounts, can lead to anemia, which in turn can cause fatigue and weakness.
Diagnosis and Treatment of bleeding disorders
Diagnosis typically involves blood tests to measure clotting factor levels, assess platelet function, and evaluate the time it takes for blood to clot. Genetic testing may also be performed to identify specific mutations.
Treatment depends on the type and severity of the disorder but may include:
Factor Replacement Therapy: Regular infusions of clotting factors for people with hemophilia or other factor deficiencies.
Antifibrinolytics: Medications that help prevent clots from breaking down.
Hormonal Therapy: To reduce menstrual bleeding in women with bleeding disorders.
Platelet Transfusions: For severe platelet function disorders.
Management of bleeding disorders is complex and requires coordination across various medical disciplines, including hematology, surgery, and sometimes genetics, to provide optimal care and improve quality of life for affected individuals.
Tell me about thrombophilia
Excessive Clotting Disorders (Thrombophilia)
Thrombophilia increases the risk of developing abnormal blood clots in veins or arteries, which can be life-threatening if they travel to the lungs, brain, or heart. Here are some primary forms:
Hereditary Thrombophilia:
Factor V Leiden Mutation: The most common hereditary thrombophilia in people of European descent, resulting from a mutation that makes blood clots more likely to form.
Prothrombin G20210A Mutation: A genetic variation that leads to increased levels of prothrombin, a protein important for blood clotting, thereby increasing the risk of clotting.
Protein C, S, and Antithrombin Deficiency: These proteins naturally help to prevent excessive clotting by inactivating certain clotting factors. Deficiencies in these proteins can lead to an increased risk of developing blood clots.
Acquired Thrombophilia:
These are conditions that aren’t inherited but develop because of another condition or certain environmental factors:
Antiphospholipid Syndrome (APS): An autoimmune disorder characterized by the production of antibodies against phospholipids, substances that make up a significant part of the cell membrane, leading to increased clot formation.
Cancer: Certain cancers, especially pancreatic, ovarian, and lung cancer, can increase clotting risk, partly due to the production of pro-coagulant substances by cancer cells.
Pregnancy: Pregnancy increases clotting factors and decreases anticoagulants, raising thrombosis risk.
Treatment for thrombophilia often involves anticoagulant medications (“blood thinners”), such as warfarin, heparin, or newer oral anticoagulants, to reduce the risk of clot formation.
