Haemostasis- Conditions Flashcards
What is DIC?
Disseminated intravascular coagulation
Excessive and inappropriate activation of the haemostatic system
What causes DIC?
Multiple Clotting Factor Deficiency
- sepsis
- obstetric emergencies
- malignancy
- hypovolaemic shock
Microvascular thrombus formation - end organ failure
Clotting factor consumption - bruising, purpura, generalised bleeding
Presentation of DIC
Acute illness and shock
Ranges from no bleeding to profound haemorrhage
- Bleeding may occur from the mouth, nose and venepuncture sites, and there may be widespread ecchymoses - Thrombotic events - any organ may be involved but the skin, brain and kidneys are most often affected
Investigations for DIC
Bloods-
PT, APTT, TT very prolonged
Fibrinogen levels reduced
High D-dimer (intense fibrinolytic activity)
Thrombocytopenia
Fragmented RBC on film
Management for DIC
Treat underlying cause
Replacement therapy-
Platelets, plasma, fibrinogen
What is haemophilia?
X-linked recessive hereditary disorder
Leads to abnormally prolonged bleeding that episodically recurs
What causes haemophilia?
Single clotting factor deficiency
Depends on type
Haemophilia A -> factor VIII deficiency
Haemophilia B -> factor IX deficiency
A is 5x more common than B
Pathophysiology of haemophilia
Primary haemostasis is normal
Common to bleed from medium and large vessels into joints
Presentation of haemophilia
In mild cases-
Bleeding after injury or surgery
Severe cases-
Recurrent haemarthroses into hinge joints, soft tissue bleeds, toddler bruising, prolonged bleeding after dental extractions, surgeries and other invasive procedures
Investigations for haemophilia
Isolated prolonged aPTT (as this tests for intrinsic pathway function)
Normal PT and TT
Coag factor assays -> factor VIII
How is haemophilia managed?
Factor replacement therapy (A8 B9)
Prophylaxis of clotting factors preventing spontaneous bleeding (common in severe)
Desmopressin stimulates vWF release
Tranexamic acid- anti-fibrinolytics
What is a complication of the replacement infusions?
Autoantibodies may be formed making it ineffective
What is Von WIllerbrand disease
Deficiency of vWF
What causes VW disease?
Autosomal dominant chromosome 12 mutation
What is the pathophysiology behind VWF deficiency ?
VWF plays role in platelet adhesion -> deficiency means defective temporary platelet plug
Also can lead to factor VIII deficiency
How does VW disease present?
Depends on severity
Can be mild bleeding after minor trauma, nosebleeds and menorrhagia, to severe bleeding for prolonged time
Investigations for VW disease
FBC- microcytic or low platelet
APTT may be long if factor 8 affected, but normal PT
VWF antigen test
How is VW disease treated?
Conservative management
In severe cases-
Desmopressin or tranexamic acid
New but replacement therapy
What is TTP?
Rare thrombotic microangiopathy
What is TTP characterised by?
Microangiopathic haemolysis, thrombocytopenia, and neuro involvement
What causes TTP?
Metalloproteinase ADAMTS13 deficiency
Triggered by medication, AIDS, malignancy
Presentation of TTP
Pentad of:
fever
haemolytic anaemia
thrombocytopenia
acute renal failure
neurological symptoms
How is TTP investigated?
Bloods consistent with haemolysis-
Schistocytes and high retic
May have elevated creatinine, LDH, and bilirubin
Urinalysis- proteinuria and haematuria
How is TTP treated?
IV plasma exchange with IV methylprednisone and rituximab
Splenectomy as last resort or recurrent relapses
