Podcast
Questions and Answers
What is the purpose of the TT test in dental management?
What is the purpose of the TT test in dental management?
What does the PT test for?
What does the PT test for?
When should a dentist avoid intra muscular injection in a patient with mild to severe factor VIII deficiency?
When should a dentist avoid intra muscular injection in a patient with mild to severe factor VIII deficiency?
Which therapy is the PFA-100 test used to screen for?
Which therapy is the PFA-100 test used to screen for?
Signup and view all the answers
What is the purpose of the aPTT test in dental management?
What is the purpose of the aPTT test in dental management?
Signup and view all the answers
When should complex oral surgery require factor replacement?
When should complex oral surgery require factor replacement?
Signup and view all the answers
Study Notes
Bleeding Disorders
- Below 50,000 platelets/cubic mm leads to excessive bleeding after minor trauma, with symptoms such as skin and mucosal purpura.
- 20,000 platelets/cubic mm can lead to spontaneous bleeding.
- Bleeding time (BT) is used to screen for disorders of platelet dysfunction and thrombocytopenia.
Coagulation Tests
- Thrombin time (TT): thrombin is added to a patient's blood sample to convert fibrinogen into insoluble fibrin, which makes up the essential clot.
- Normal TT is 9-13 seconds; 16-18 seconds is considered prolonged, usually caused by excessive plasmin and/or fibrin-split products.
Disorders of the Common Pathway
- Prolonged aPTT and PT indicates a common pathway factor deficiency.
- Congenital deficiency of factor V, X, prothrombin, and fibrinogen are rare, while acquired deficiency is indicated by conditions such as vitamin K deficiency and liver diseases.
Medical Management
- Vascular defects: hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu disease) is an autosomal dominant disorder characterized by telangiectasia lesions involving the skin and mucous membranes, leading to bleeding due to inert mechanical fragility of the vessels.
Hereditary Disorders of Connective Tissue
- Ehlers-Danlos syndrome, osteogenesis imperfecta, and Marfan syndrome are characterized by abnormal vessel wall weakness, leading to bleeding.
Acquired Connective Tissue Disorders
- Scurvy (vitamin C deficiency) causes capillary fragility and delayed wound healing.
- Long-term steroid therapy can lead to thinning of connective tissue, resulting in bleeding.
- Serum sickness can lead to purpura through immune complex deposits in vessel walls.
Platelet Disorders
- Von Willebrand disease is the most common disorder, caused by an autosomal dominant trait, leading to mild to moderate bleeding due to a defect in platelet adhesion.
- vWF factor is necessary for carrying factor VIII and allowing platelet adhesion to tissue.
Laboratory Investigation and Treatment
- PT and TT are normal in von Willebrand disease.
- PFA-100 and aPTT are prolonged, while platelet count is normal.
- Immunoassay of vWF and specific assays for factor VIII are necessary to establish the diagnosis and type of vWD.
- Treatment involves cryoprecipitate, and PT is used to monitor warfarin therapy.
Anti-Platelet Drugs and Dental Management
- Anti-platelet treatment reduces overall mortality from vascular complications by 30%.
- Aspirin and nonsteroidal anti-inflammatory drugs (such as ibuprofen) inhibit platelet function.
- Detection of bleeding disorders involves a thorough history, clinical examination, and laboratory tests such as PT, aPTT, TT, and platelet count.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on anticoagulation therapy and antiplatelet drugs with this quiz. Learn about the use of PT and INR in monitoring warfarin therapy, the role of antiplatelet drugs in reducing vascular complications, and the mechanisms of action of aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs).
