Podcast
Questions and Answers
What is the primary role of primary haemostasis?
What is the primary role of primary haemostasis?
- Vasoconstriction of blood vessels
- Formation of fibrin strands
- Interaction between blood vessels, platelets, and vWF (correct)
- Degradation of the fibrin clot
Which mechanism is responsible for the removal of blood clots following wound healing?
Which mechanism is responsible for the removal of blood clots following wound healing?
- Vascular tone regulation
- Secondary haemostasis
- Primary haemostasis
- Fibrinolysis (correct)
What role does thrombomodulin play in haemostasis?
What role does thrombomodulin play in haemostasis?
- Inhibits platelet function
- Activates platelets
- Binds free thrombin (correct)
- Promotes vessel constriction
Which component of the blood vessel wall is primarily responsible for regulating vascular tone?
Which component of the blood vessel wall is primarily responsible for regulating vascular tone?
What does the presence of von Willebrand factor facilitate?
What does the presence of von Willebrand factor facilitate?
What is a crucial function of protein C in the coagulation process?
What is a crucial function of protein C in the coagulation process?
Which substance acts as a potent vasoconstrictor released by endothelial cells?
Which substance acts as a potent vasoconstrictor released by endothelial cells?
What is the function of tissue plasminogen in the clotting process?
What is the function of tissue plasminogen in the clotting process?
What is the initial role of vWF in platelet adhesion?
What is the initial role of vWF in platelet adhesion?
What triggers the extrinsic coagulation pathway?
What triggers the extrinsic coagulation pathway?
Which of the following best describes the propagation stage of coagulation?
Which of the following best describes the propagation stage of coagulation?
How does thrombin contribute to the coagulation process?
How does thrombin contribute to the coagulation process?
What is the role of FXIIIa in fibrin formation?
What is the role of FXIIIa in fibrin formation?
Which factor acts as a cofactor for the activation of FXA?
Which factor acts as a cofactor for the activation of FXA?
What is the function of antithrombin in coagulation?
What is the function of antithrombin in coagulation?
How does the intrinsic pathway initiate the coagulation cascade?
How does the intrinsic pathway initiate the coagulation cascade?
What effect does thrombin have on platelets during coagulation?
What effect does thrombin have on platelets during coagulation?
What causes platelets to roll along the exposed collagen after initial adhesion?
What causes platelets to roll along the exposed collagen after initial adhesion?
Which condition is commonly caused by intrinsic factor deficiency leading to B12 malabsorption?
Which condition is commonly caused by intrinsic factor deficiency leading to B12 malabsorption?
What is the primary method for assessing B12 absorption abnormalities?
What is the primary method for assessing B12 absorption abnormalities?
Which of the following is NOT a cause of folate deficiency?
Which of the following is NOT a cause of folate deficiency?
What does the presence of radiolabeled B12 in the urine indicate after administering an oral dose?
What does the presence of radiolabeled B12 in the urine indicate after administering an oral dose?
What is the primary storage site for iron in the body?
What is the primary storage site for iron in the body?
Which vitamin is required for the reduction of ferric iron (Fe3+) to ferrous iron (Fe2+) in the intestine?
Which vitamin is required for the reduction of ferric iron (Fe3+) to ferrous iron (Fe2+) in the intestine?
What is a primary risk factor for developing anemia?
What is a primary risk factor for developing anemia?
How is iron primarily delivered to developing erythroid precursors?
How is iron primarily delivered to developing erythroid precursors?
What is the effect of intrinsic factor on B12 absorption?
What is the effect of intrinsic factor on B12 absorption?
Which of the following conditions can lead to reduced red blood cell survival?
Which of the following conditions can lead to reduced red blood cell survival?
What is the primary storage site for vitamin B12 in the body?
What is the primary storage site for vitamin B12 in the body?
Which process must occur for vitamin B12 to be properly absorbed in the intestines?
Which process must occur for vitamin B12 to be properly absorbed in the intestines?
What condition is associated with macrocytic anemia and hypersegmented neutrophils?
What condition is associated with macrocytic anemia and hypersegmented neutrophils?
What clinical feature is NOT typically associated with anemia?
What clinical feature is NOT typically associated with anemia?
Which enzyme is vitamin B12 a co-factor for in its biochemical role?
Which enzyme is vitamin B12 a co-factor for in its biochemical role?
What is the effect of vitamin B12 deficiency on homocysteine levels?
What is the effect of vitamin B12 deficiency on homocysteine levels?
What is a hallmark feature of megoblastic anemia seen in blood smears?
What is a hallmark feature of megoblastic anemia seen in blood smears?
What type of anemia develops more quickly due to a faster turnover rate of cells?
What type of anemia develops more quickly due to a faster turnover rate of cells?
What amino acid's methylation process is affected by vitamin B12 deficiency?
What amino acid's methylation process is affected by vitamin B12 deficiency?
Which laboratory finding is typically normal in cases of folate deficiency?
Which laboratory finding is typically normal in cases of folate deficiency?
What dietary source is primarily responsible for providing vitamin B12 to humans?
What dietary source is primarily responsible for providing vitamin B12 to humans?
What is the consequence of a deficiency in transcobalamin?
What is the consequence of a deficiency in transcobalamin?
How do folate deficiency and vitamin B12 deficiency differ in terms of red blood cell folate levels?
How do folate deficiency and vitamin B12 deficiency differ in terms of red blood cell folate levels?
What is the primary treatment approach for von Willebrand disease?
What is the primary treatment approach for von Willebrand disease?
Which of the following statements about hemophilia genes is true?
Which of the following statements about hemophilia genes is true?
What characterizes von Willebrand disease type 3?
What characterizes von Willebrand disease type 3?
What is a possible risk associated with the use of portacath access in hemophilia treatment?
What is a possible risk associated with the use of portacath access in hemophilia treatment?
Which symptom is most commonly associated with von Willebrand disease?
Which symptom is most commonly associated with von Willebrand disease?
Which protein is primarily responsible for transporting iron across the enterocyte basolateral membrane?
Which protein is primarily responsible for transporting iron across the enterocyte basolateral membrane?
What is the primary storage form of iron in the body?
What is the primary storage form of iron in the body?
How does Hepcidin affect iron metabolism?
How does Hepcidin affect iron metabolism?
What changes in red blood cells are typical of iron deficiency anemia?
What changes in red blood cells are typical of iron deficiency anemia?
What laboratory method is commonly used to measure serum ferritin levels?
What laboratory method is commonly used to measure serum ferritin levels?
Which test is useful for assessing iron deficiency through transferrin saturation?
Which test is useful for assessing iron deficiency through transferrin saturation?
What characteristic finds in a peripheral blood smear indicates a response to therapy in iron deficiency anemia?
What characteristic finds in a peripheral blood smear indicates a response to therapy in iron deficiency anemia?
Which factor can falsely elevate serum iron levels?
Which factor can falsely elevate serum iron levels?
Which of the following is NOT a reason for increased iron absorption leading to iron overload?
Which of the following is NOT a reason for increased iron absorption leading to iron overload?
In the case of lead poisoning, which metabolite is produced instead of iron protoporphyrin?
In the case of lead poisoning, which metabolite is produced instead of iron protoporphyrin?
What is an important consideration when collecting samples for coagulation testing?
What is an important consideration when collecting samples for coagulation testing?
What technique is utilized to measure clotting times using optical methods?
What technique is utilized to measure clotting times using optical methods?
Which of the following factors can indicate a prolonged clotting time in diagnostic testing?
Which of the following factors can indicate a prolonged clotting time in diagnostic testing?
Which study is performed to assess deficiencies in platelet function?
Which study is performed to assess deficiencies in platelet function?
What factors can prolong prothrombin time (PT)?
What factors can prolong prothrombin time (PT)?
Which of the following conditions is primarily monitored using the International Normalized Ratio (INR)?
Which of the following conditions is primarily monitored using the International Normalized Ratio (INR)?
What does a prolonged activated partial thromboplastin time (APTT) indicate?
What does a prolonged activated partial thromboplastin time (APTT) indicate?
Which test evaluates the conversion of fibrinogen to fibrin?
Which test evaluates the conversion of fibrinogen to fibrin?
What can cause elevated D-dimer levels?
What can cause elevated D-dimer levels?
In mixing studies, what indicates the presence of a factor deficiency?
In mixing studies, what indicates the presence of a factor deficiency?
What is a characteristic of Glanzmann thrombasthenia?
What is a characteristic of Glanzmann thrombasthenia?
What does the Clauss fibrinogen test measure?
What does the Clauss fibrinogen test measure?
What can result from the use of direct anticoagulants?
What can result from the use of direct anticoagulants?
Which condition is associated with the highest risk of bleeding during anticoagulant therapy?
Which condition is associated with the highest risk of bleeding during anticoagulant therapy?
What does a normal PT with an abnormal APTT suggest?
What does a normal PT with an abnormal APTT suggest?
Which of the following is true about inhibitors in coagulation?
Which of the following is true about inhibitors in coagulation?
What is the method by which vWF antigen is quantitatively determined?
What is the method by which vWF antigen is quantitatively determined?
Which of the following symptoms is commonly associated with bleeding disorders?
Which of the following symptoms is commonly associated with bleeding disorders?
In cases of vitamin K deficiency, which of the following factors is primarily affected?
In cases of vitamin K deficiency, which of the following factors is primarily affected?
What is the primary effect of disseminated intravascular coagulation (DIC) on coagulation factors?
What is the primary effect of disseminated intravascular coagulation (DIC) on coagulation factors?
Which of the following is a common cause of vitamin K deficiency?
Which of the following is a common cause of vitamin K deficiency?
Which bleeding disorder is characterized by large bruises at unusual sites?
Which bleeding disorder is characterized by large bruises at unusual sites?
Which of the following is an inherited bleeding disorder?
Which of the following is an inherited bleeding disorder?
What is the main purpose of platelet transfusions?
What is the main purpose of platelet transfusions?
How is fresh frozen plasma (FFP) stored when not in use?
How is fresh frozen plasma (FFP) stored when not in use?
In liver disease, which coagulation factor is typically the first to reduce?
In liver disease, which coagulation factor is typically the first to reduce?
What does gamma carboxylation of glutamic acid facilitate in vitamin K dependent proteins?
What does gamma carboxylation of glutamic acid facilitate in vitamin K dependent proteins?
Which treatment is more likely to be fatal in DIC cases?
Which treatment is more likely to be fatal in DIC cases?
Which of the following is a characteristic of acquired bleeding disorders?
Which of the following is a characteristic of acquired bleeding disorders?
What happens to coagulation factors during massive hemorrhage?
What happens to coagulation factors during massive hemorrhage?
What type of antibodies may develop in patients with certain bleeding disorders?
What type of antibodies may develop in patients with certain bleeding disorders?
Flashcards
Primary Haemostasis
Primary Haemostasis
The initial phase of haemostasis, involving the interaction of blood vessels, platelets, and von Willebrand factor to form a temporary plug at the site of injury.
Secondary Haemostasis
Secondary Haemostasis
The second phase of haemostasis, where coagulation factors interact to form a stable fibrin clot.
Fibrinolysis
Fibrinolysis
The process of breaking down a blood clot after wound healing to prevent blockage of blood vessels.
Von Willebrand Factor (vWF)
Von Willebrand Factor (vWF)
Signup and view all the flashcards
Endothelial cells
Endothelial cells
Signup and view all the flashcards
Coagulation Factors
Coagulation Factors
Signup and view all the flashcards
Haemostasis
Haemostasis
Signup and view all the flashcards
Anticoagulant Properties
Anticoagulant Properties
Signup and view all the flashcards
Vessel Injury
Vessel Injury
Signup and view all the flashcards
Platelet Adhesion
Platelet Adhesion
Signup and view all the flashcards
Platelet Activation
Platelet Activation
Signup and view all the flashcards
Platelet Plug Formation
Platelet Plug Formation
Signup and view all the flashcards
Coagulation Cascade
Coagulation Cascade
Signup and view all the flashcards
Extrinsic Pathway
Extrinsic Pathway
Signup and view all the flashcards
Thrombin Role
Thrombin Role
Signup and view all the flashcards
Fibrin Formation
Fibrin Formation
Signup and view all the flashcards
Natural Inhibitors
Natural Inhibitors
Signup and view all the flashcards
Thrombin
Thrombin
Signup and view all the flashcards
Thrombomodulin
Thrombomodulin
Signup and view all the flashcards
Protein C
Protein C
Signup and view all the flashcards
Protein S
Protein S
Signup and view all the flashcards
Megaloblastic Anemia
Megaloblastic Anemia
Signup and view all the flashcards
Vitamin B12 (Cobalamin)
Vitamin B12 (Cobalamin)
Signup and view all the flashcards
Intrinsic Factor
Intrinsic Factor
Signup and view all the flashcards
Folate
Folate
Signup and view all the flashcards
Macrocytosis
Macrocytosis
Signup and view all the flashcards
Hypersegmented Neutrophils
Hypersegmented Neutrophils
Signup and view all the flashcards
Serum B12
Serum B12
Signup and view all the flashcards
Serum Folate
Serum Folate
Signup and view all the flashcards
Homocysteine
Homocysteine
Signup and view all the flashcards
Methylmalonic Acid (MMA)
Methylmalonic Acid (MMA)
Signup and view all the flashcards
Red Cell Folate
Red Cell Folate
Signup and view all the flashcards
Causes of B12 deficiency
Causes of B12 deficiency
Signup and view all the flashcards
Causes of Folate deficiency
Causes of Folate deficiency
Signup and view all the flashcards
Schilling Test
Schilling Test
Signup and view all the flashcards
Schilling Test 1 - Step 1
Schilling Test 1 - Step 1
Signup and view all the flashcards
Schilling Test 1 - Step 2
Schilling Test 1 - Step 2
Signup and view all the flashcards
Anemia mechanism (reduced RBC formation)
Anemia mechanism (reduced RBC formation)
Signup and view all the flashcards
Iron absorption
Iron absorption
Signup and view all the flashcards
Anemia definition
Anemia definition
Signup and view all the flashcards
Iron role in anemia
Iron role in anemia
Signup and view all the flashcards
B12 treatment
B12 treatment
Signup and view all the flashcards
Haemophilia A
Haemophilia A
Signup and view all the flashcards
Haemophilia B
Haemophilia B
Signup and view all the flashcards
Lyonization
Lyonization
Signup and view all the flashcards
What are the types of VWD?
What are the types of VWD?
Signup and view all the flashcards
Treatment for VWD
Treatment for VWD
Signup and view all the flashcards
Divalent Metal Transporter 1 (DMT1)
Divalent Metal Transporter 1 (DMT1)
Signup and view all the flashcards
Haem Carrier Protein (HCP1)
Haem Carrier Protein (HCP1)
Signup and view all the flashcards
Haem Oxygenase
Haem Oxygenase
Signup and view all the flashcards
Ferroportin
Ferroportin
Signup and view all the flashcards
Hephaestin
Hephaestin
Signup and view all the flashcards
Ferritin
Ferritin
Signup and view all the flashcards
Haemosiderin
Haemosiderin
Signup and view all the flashcards
Hepcidin
Hepcidin
Signup and view all the flashcards
Iron Overload
Iron Overload
Signup and view all the flashcards
Iron Deficiency
Iron Deficiency
Signup and view all the flashcards
Anisocytosis
Anisocytosis
Signup and view all the flashcards
Poikilocytosis
Poikilocytosis
Signup and view all the flashcards
Target Cells
Target Cells
Signup and view all the flashcards
Serum Ferritin
Serum Ferritin
Signup and view all the flashcards
Serum Iron
Serum Iron
Signup and view all the flashcards
Platelet Function Tests
Platelet Function Tests
Signup and view all the flashcards
Glanzmann Thrombasthenia
Glanzmann Thrombasthenia
Signup and view all the flashcards
Bernard-Soulier Syndrome
Bernard-Soulier Syndrome
Signup and view all the flashcards
What does Prothrombin Time (PT) assess?
What does Prothrombin Time (PT) assess?
Signup and view all the flashcards
What factors affect PT?
What factors affect PT?
Signup and view all the flashcards
What is INR?
What is INR?
Signup and view all the flashcards
What is APTT?
What is APTT?
Signup and view all the flashcards
What factors affect APTT?
What factors affect APTT?
Signup and view all the flashcards
Interpretation of Clotting Screen
Interpretation of Clotting Screen
Signup and view all the flashcards
Clauss Fibrinogen Test
Clauss Fibrinogen Test
Signup and view all the flashcards
Fibrinogen Results Interpretation
Fibrinogen Results Interpretation
Signup and view all the flashcards
What does Thrombin Time (TT) measure?
What does Thrombin Time (TT) measure?
Signup and view all the flashcards
What are D-Dimers?
What are D-Dimers?
Signup and view all the flashcards
Bleeding Time Test
Bleeding Time Test
Signup and view all the flashcards
Mixing Studies
Mixing Studies
Signup and view all the flashcards
Factor Assays
Factor Assays
Signup and view all the flashcards
Vitamin K Deficiency
Vitamin K Deficiency
Signup and view all the flashcards
Vitamin K's Role
Vitamin K's Role
Signup and view all the flashcards
Liver Disease and Clotting
Liver Disease and Clotting
Signup and view all the flashcards
Massive Haemorrhage
Massive Haemorrhage
Signup and view all the flashcards
Platelet Transfusions
Platelet Transfusions
Signup and view all the flashcards
Fresh Frozen Plasma (FFP)
Fresh Frozen Plasma (FFP)
Signup and view all the flashcards
Cryoprecipitate
Cryoprecipitate
Signup and view all the flashcards
Disseminated Intravascular Coagulation (DIC)
Disseminated Intravascular Coagulation (DIC)
Signup and view all the flashcards
DIC Triggers
DIC Triggers
Signup and view all the flashcards
Autoantibodies/Inhibitors
Autoantibodies/Inhibitors
Signup and view all the flashcards
Inherited Bleeding Disorders
Inherited Bleeding Disorders
Signup and view all the flashcards
Acquired Bleeding Disorders
Acquired Bleeding Disorders
Signup and view all the flashcards
Treatment for Bleeding Disorders
Treatment for Bleeding Disorders
Signup and view all the flashcards
Study Notes
Haemostasis
- Haemostasis is the body's normal response to prevent bleeding.
- Crucial functions include maintaining blood fluidity, limiting bleeding after injury, and removing clots after healing.
- The clotting trilogy involves blood vessels, platelets, and coagulation factors.
- Primary haemostasis involves blood vessels, platelets, and von Willebrand factor (vWF) to form a primary haemostatic plug.
- Secondary haemostasis involves coagulation factors to strengthen the clot with fibrin strands.
- Fibrinolysis degrades the fibrin clot after wound healing to prevent blockage.
Blood Vessel Wall
- The blood vessel wall consists of three layers: intima, media, and adventitia.
- The intima is the inner layer with endothelial cells.
- The media is the smooth muscle layer that regulates vascular tone.
- The adventitia is the outer layer of collagen and fibroblasts that anchors and protects the vessel.
Anticoagulant Properties
- Prostacyclin and nitric oxide inhibit platelet function and dilate vessels.
- Thrombomodulin binds thrombin, preventing clotting factor activation.
- Heparin sulphate and endothelial protein C activate protein C, a natural anticoagulant.
- Protein C inactivates factors V and VIIa.
- Heparin sulphate enhances antithrombin's inhibition of coagulation factors.
- Protein S is a cofactor for protein C, binding to activated platelets.
- Tissue plasminogen activator promotes clot lysis.
Procoagulant Properties
- Endothelial cells release endothelial-1, a vasoconstrictor.
- Adventitia cells express tissue factor, vital for initiating the coagulation cascade via FVIIa.
- Thromboxane A2 and PAF activate platelets via vWF on the endothelial cell wall.
- Plasminogen activator inhibitor (PAI-1) inhibits fibrinolysis.
Von Willebrand Factor (vWF)
- vWF is a large glycoprotein produced by endothelial cells and platelets.
- It's crucial for platelet adhesion to sites of vascular injury.
- vWF is regulated and cleaved by ADAMTS13.
- It carries ABO antigens and increases FVIIa plasma half-life.
Vessel Injury
- Exposed procoagulant material triggers haemostasis.
- Endothelial-1 causes vasoconstriction, reducing blood loss and promoting platelet aggregation.
- Exposed vWF recruits circulating platelets via GPIb receptors.
- Platelets, located at the edge of vessels, quickly respond to damage.
Platelets
- Platelet adhesion occurs to the subendothelial matrix (directly or via vWF).
- Platelet rolling occurs due to blood flow, facilitating further vWF-GPIb interactions.
- Platelet activation recruits more platelets to the injury site.
- Platelet plug formation occurs via fibrinogen bridging activated platelets.
Secondary Haemostasis
- The platelet plug alone is insufficient for complete haemostasis.
- Secondary haemostasis, involving coagulation, is initiated concurrently with primary haemostasis.
- This process converts soluble fibrinogen into insoluble fibrin.
Coagulation Factors
- Coagulation factors interact in a complex system through enzyme activation.
- Coagulation factors are serine proteases.
- Some require cofactors for optimal activation.
- Activation generally happens at membrane surfaces due to factor and precursor binding to phospholipids, calcium, or receptors.
- This localisation directs the haemostasis response.
Coagulation Cascade
- Inactive zymogens are sequentially activated to active enzymes.
- The intrinsic pathway uses plasma-based factors.
- The extrinsic pathway requires a tissue factor initiator and plasma-based factors.
- Both pathways converge to generate the fibrin clot.
Extrinsic Pathway
- Tissue factor, exposed by endothelial injury, binds FVII, activating it.
- The TF-FVIIa complex activates FX.
- FXa forms the prothrombinase complex with FVa, phospholipids, and calcium, which converts prothrombin (FII) to thrombin.
- FXIIIa cross-links fibrin for a stronger mesh.
Amplification Stage
- Thrombin generation initiates amplification.
- Thrombin activates factors V, VIII, and platelets.
- FVa is a cofactor for FXa.
- FIXa binds the activated platelet surface.
- Increased thrombin availability is achieved at the activated platelet surface.
Propagation Stage
- FVIIIa is formed during the amplification stage.
- FIXa and FVIIIa form the tenase complex with FX.
- This tenase complex is more efficient than the TF-FVIIa complex, activating more thrombin.
Thrombin Role
- Thrombin cleaves fibrinogen to fibrin.
- Thrombin activates factors V, VIII, IX, XI, and XII, platelets, protein C, and thrombin-activatable fibrinolysis inhibitor (TAFI).
- Thrombin produces chemokines to attract WBCs to the injury site.
- Thrombin promotes tissue repair.
Fibrin Formation
- Thrombin converts soluble fibrinogen to insoluble fibrin.
- Fibrin is reinforced by FXIIIa, which forms cross-links.
- FXIIIa also binds a2-antiplasmin to inhibit plasmin degradation of the clot.
Natural Inhibitors
- Natural inhibitors prevent inappropriate clotting cascade activation.
- These include antithrombin (inhibits several serine proteases, enhanced by heparin sulphate), protein C (inactivates factors V and VIIIa, requiring protein S as a cofactor), and tissue factor pathway inhibitor (TFPI).
- Antithrombin, protein C, and Protein S, and TFPI are vital in preventing inappropriate clotting.
Megaloblastic Anaemias
- Megaloblastic anemias arise from delayed erythroblast nucleus maturation relative to cytoplasm, resulting in asynchronous maturation.
- Deficiencies in vitamin B12 or folate, or abnormalities in their metabolism are common causes.
Vitamin B12
- Vitamin B12 (cobalamin) is obtained from animal products, stored primarily in the liver.
- The body can store enough B12 for 3-4 years, making short-term deficiencies less critical.
- B12 absorption requires intrinsic factor, produced by parietal cells in the stomach.
- B12-intrinsic factor complex is absorbed in the terminal ileum. The complex is then bound to transcobalamin and absorbed, delivering B12 to bone marrow.
Folate
- Folate is needed for DNA synthesis and must be preformed in the diet.
- Folates are absorbed as methyltetrahydrofolate in the upper small intestine.
- Folate reserves are smaller than B12, due to rapid cell turnover.
Folate and B12 Interaction
- B12 is a co-factor for methionine synthetase, needed to convert methyl-tetrahydrofolate to tetrahydrofolate (THF).
- This reaction also converts homocysteine to methionine.
- Folate deficiency also affects DNA synthesis.
Clinical Features of Anemia
- Weakness, shortness of breath, pallor, jaundice, glossitis, nervous system disturbances, psychiatric disturbances.
Lab Findings
- Macrocytosis (ovalocytes), anisocytosis, hypersegmented neutrophils, Howell-Jolly bodies, basophilic stippling, increased serum bilirubin and lactate dehydrogenase.
- Serum iron and ferritin are generally normal in megaloblastic anemias. B12 deficiency often shows lower serum B12 levels but not always.
- Red cell folate helps diagnose folate deficiency, but B12 deficiency can also cause this test to be falsely low.
- Serum homocysteine is elevated in both folate and B12 deficiencies, while methylmalonic acid (MMA) is elevated only in B12 deficiency.
Causes of Deficiencies
- B12 deficiency causes include intrinsic factor deficiency (pernicious anemia), transcobalamin deficiency, and malabsorption.
- Folate deficiency causes include poor intake of folate-rich foods, pregnancy, some medications.
Schilling Test (Obsolete)
- The Schilling test, used to diagnose B12 malabsorption, uses radiolabeled B12.
- This test is now less common due to difficulty in obtaining isotopes.
Anemia
- Anemia is a reduction in red blood cell count or function, leading to reduced oxygen-carrying capacity.
- It is defined by low haemoglobin levels.
Iron Role in Haemostasis and Anemia
- Iron is essential for red blood cell synthesis.
- Transferrin transports iron.
- Iron is stored primarily in the liver as ferritin and hemosiderin.
Iron Absorption
- Iron is absorbed by enterocytes in the duodenum.
- Ferric iron (Fe3+) is reduced to ferrous iron (Fe2+) before absorption.
- Haem iron is absorbed more readily than non-haem iron.
- Hephaestin oxidises ferrous iron to ferric iron.
Iron Deficiency Anemia
- Patients often have microcytic, hypochromic red blood cells.
- Lab results often show low serum ferritin, low serum iron, and high total iron-binding capacity.
- Transferrin saturation is usually low.
Lab Investigation of Coagulation
- Primary haemostasis tests involve platelet function.
- Secondary haemostasis tests include PT, APTT, fibrinogen, TT, and d-dimers.
- Investigations include mixing studies, factor assays, and inhibitor assays. Sampling is crucial for accurate testing.
Bleeding Disorders
- Acquired disorders include vitamin K deficiency, liver disease, massive hemorrhage, DIC, and autoantibodies.
- Inherited disorders include hemophilia, vWD, Bernard-Soulier syndrome, and Glanzmann thrombasthenia.
- Vitamin K deficiency affects factors II, VII, IX, X, protein C, and protein S.
- Liver disease impacts clotting factor production.
- Massive hemorrhage can cause consumptive coagulopathies.
- DIC causes a consumptive coagulopathy.
- Autoantibodies/inhibitors can target clotting factors.
Hemophilia
- Hemophilia is an X-linked bleeding disorder.
- Hemophilia A involves factor VIII deficiency, and Hemophilia B involves factor IX deficiency.
- Treatment involves prophylaxis with plasma-derived or recombinant clotting factors.
Von Willebrand Disease
- von Willebrand disease is an inherited bleeding disorder with variable severity.
- Types include type 1 (partial quantitative deficiency), type 2 (qualitative dysfunction), and type 3 (total deficiency) of vWF.
- Treatment includes desmopressin, vWF/factor VIII concentrates, antifibrinolytics, and topical agents.
Platelet Disorders
- Platelet disorders include thrombocytopenia (reduced platelet count) and defective platelet function.
- Treatment can include platelet transfusions.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the essential mechanisms of haemostasis, including the roles of blood vessels, platelets, and coagulation factors in preventing bleeding. This quiz covers primary and secondary haemostasis as well as the structure of blood vessel walls and the anticoagulant properties that regulate clot formation.
