Bleeding disorders Flashcards
What is the diagnostic triad of bleeding?
- Personal Hx of bleeding
- Family Hx of bleeding
- Supportive laboratory test
What do you look for in a personal Hx when looking to diagnose bleeding disorders?
- Bruising
- Epistaxis (nosebleed)
- GI tract
- Menses
- Urine (Haematuria)
- Surgical Hx
- Dental Hx
- Cuts and injuries
What do you look for in a family Hx when looking to diagnose bleeding disorders?
- Known bleeding disorders
* Bleeding in family members especially after surgery or dentistry
What blood tests would you order for a suspected bleeding disorder?
Platelets:
- FBC
- Microscopy
- Platelet function assay
- Specialist tests
Coagulation:
- Prothrombin time (PT)
- Activated partial thromboplastin time (APTT)
- Thrombin time (TT)
- Clauss Fibrinogen
- 50/50 mixture test
Test of clot stability
- Euglobin clot lysis
- Factor XIII assay
- PAI-D
What is the normal range for Prothrombin time?
10-14s
What does the Prothrombin time measure?
The extrinsic system in the coagulation pathway – factors II, V, VII and X
What is the normal range of INR?
0.9-1.2
What is the normal range for Activated partial thromboplastin time
22-36s
What does the Activated partial thromboplastin time measure?
The intrinsic system in the coagulation pathway – factors VIII, IX, XI, XII and Von Willebrand factor
What does a quick Activated partial thromboplastin time mean?
Increased thrombus formation
What does a slow Activated partial thromboplastin time mean?
Increases bleeding
When is the Activated partial thromboplastin time usually ordered?
When a patient is on heparin
What does the thrombin time measure?
The rate of conversion of fibrinogen to fibrin when thrombin has been introduced
What is a 50/50 mixture test?
Mix 50% of patient’s plasma with 50% normal plasma
In a 50/50 mixture test, what does it show if the PT and APTT correct?
There is a factor deficiency
In a 50/50 mixture test, what does it show if the PT and APTT are still prolonged?
There is a factor inhibitor
What can cause prolonged PT?
- Warfarin
Most common
- VII
Second most common
- II
- V
- XWhat can cause prolonged APTT?
- Heparin
- VIII
- IX
- XI
- XII
- Von Willebrand’s disease
In types I and II, APTT is often normal
What are the vitamin K dependent factors?
- Factor II
- Factor VII
- Factor IX
- Factor X
- Protein C
- Protein S
What can cause a prolonged PT and APTT?
• Vitamin K deficiency • DIC = Disseminated Intravascular Coagulation • Heparin toxicity • Deficiencies of Factor V or Factor X o Rare
What can cause vitamin K deficiency?
Liver disease or malabsorption
What test would you order if the clotting tests came back as negative, but there is still a history of bleeding?
Von Willebrand’s tests:
- VIII
- vWF antigen
- vWF activity
What is DIC (Disseminated Intravascular Coagulation)?
Processes of coagulation and fibrinolysis are dysregulated causing widespread clotting with resultant bleeding
What can cause DIC (Disseminated Intravascular Coagulation)?
- Sepsis
- Trauma
- Obstetric complications
- Malignancy
How do you diagnose DIC (Disseminated Intravascular Coagulation)?
- Low platelets
- Prolonged PT, APTT
- Fibrin degradation products raised
- Schistocytes due to microangiopathic haemolytic anaemia
