A to E: Circulation - Bleeding disorders

Question 1

Outline the clotting cascade

Answer 1

• Intrinsic (aPTT): collagen in vascular endotherlium
• Extrinsic (PT): tissue factor on extravascular cells

Question 2

How are bleeding disorders classified?

Answer 2

• Congenital
• Acquired

Question 3

Name two congenital bleeding disorders

Answer 3

• Von Willebrand’s disease:
  
  • Reduction or abnormality of vWF
  • Commonest inherited bleeding disorder
• Haemophilia A and B (Factor VIII and IX deficiency)
  
  • X-linked recessive

Question 4

Name four acquired bleeding disorders

Answer 4

• Liver disease; cirrhosis
  
  • Impaired clotting protein synthesis; thrombocytopenia
• Vitamin K deficiency: dietary; malabsorption; newborn
• DIC following shock; sepsis; or malignancy
  
  • Microvascular thrombosis + generalised bleeding
  • Massive consumption of coagulation factors
• Renal disease
  
  • Platelet dysfunction
• Autoimmune: Lymphoma; SLE; ITP
• Amyloidosis
• Vitamin C deficiency

Question 5

Give two presenting features of bleeding disorders

Answer 5

• Bruising: spontaneous or recurrent
• Prolonged bleeding
  
  • Epistaxis >10min
  • Severe menorrhagia causing anaemia (normal uterus)
  • Bleeding gums without gingival disease
  • After dental extraction; postpartum; post-op

Question 6

Differentiate between the presentation of vWD and haemophilia

Answer 6

• vWD: Petechiae and mucosal bleeds
• Haemophilia: Haemarthrosis

Question 7

Request four investigations for suspected bleeding disorders

Answer 7

• FBC; platelet count
• Blood film
• APTT (intrinsic)
  
  • Heparin monitoring; coagulation factor deficiencies; haemophilia A and B
• PT (extrinsic and common)
  
  • Warfarin; vitamin K deficiency; liver dysfunction
• Thrombin clotting time
  
  • DIC; liver disease
• Specific factor assays ^eg. factor VIII; IX; vWF
• Bone marrow biopsy
• U+Es; LFTs: hepatic and renal acquired bleeding disorders

Question 8

What is Von Willebrand’s disease?

Answer 8

• Commonest inherited bleeding disorder
  
  • Typically, autosomal dominant
• Abnormal or reduced vWF
  
  • Normally promotes platelet adhesion to damaged endotherlium; carrier molecule for factor VIII

Question 9

Outline the management of von Willebrand’s disease

Answer 9

• Mild: Tranexamic acid
• Desmopressin
  
  • Increases factor VIII and vWF from endothelial stores
• Serious/surgical prophylaxis: F VIII concentrate with vWF

Question 10

What is the target INR for the majority of patients on warfarin?

Outline the exceptions to this

Answer 10

Target INR of 2.5 for majority

Exceptions:

• Recurrent DVT whilst on warfarin (3.0-3.5)
• Arterial antiphospholipid syndrome (3.5)

Question 11

Outline the management of an above-range INR with no/minor bleeding

Answer 11

• INR <5.0:
  
  • Stop/pause warfarin
  • Review cause and reduce warfarin
  • Monitor closely
• INR 5.0-8.0:
  
  • No bleeding: same as above
  • Minor: stop warfarin; Vit K PO/IV
• INR >8.0:
  
  • No bleed: stop warfarin; consider Vit K PO
  • Minor: stop warfarin; Vit K IV; consider admission

Question 12

Outline the management of bleeding for patients on warfarin

Answer 12

• ABC assessment
  
  • Haemodynamic stability
  • Identify source of bleeding
  • INR and last warfarin dose
• Stratify
  
  • Clinically relevant non-major bleeding
  • Major bleeding
• Treat
  
  • CRNM: Vit K 1-3mg IV
  • Major: Vit K 5-10mg IV; PCC (Octaplex/Beriplex)

Question 13

How is heparin reversed?

Answer 13

Protamine sulfate