Bleeding disorders Flashcards
What does APTT measure?
Intrinsic pathway factors VIII, IX, XI, XII
What does PT measure?
Extrinsic pathway factors factor VII
What does TCT measure?
Conversion of fibrogen to fibrin clot
What does bleeding time measure?
Primary haemostasis e.g. platelet function
What are causes of an isolated prolonged PT?
Factor deficiency
Liver disease
Drugs e.g. warfarin apixaban..
Liver disease can however cause PT and APTT prolongation
What are causes of isolated prolonged APTT?
Haemophilias
Lupus anticoagulants
Factor deficiencies
Heparin (PT sometimes prolonged)
VWF, along with prolonged bleeding time
What are causes of prolonged PT and APTT?
Liver disease DIC Common pathway deficiencies e.g II, V, X Combination factors deficiencies Vitamin K deficiency
Anticoagulation
What are causes of prolonged bleeding time?
Aspirin (isolated prolonged)
DIC
How is warfarin over-anticoagulation identified and treated?
May present with IC bleed, other bleeding.
INR prolonged
Stopping and/or reducing dose
Oral or IV vitamin K
IV coagulation factors
How does haemophilia present and how is it treated
A = 8 (X-r) B = 9 (X-r) C = 11 (A-r)
Often presents with haemarthroses with prolonged APTT.
Give tranexamic acid, DDAVP, recombinant factor.
What is VWD?
Reduction in functioning VWF.
most common inherited bleeding disorder
Autosomal dominant
How does VWD present?
Symptoms of platelet disorder e.g. epistaxis, menorrhagia
Prolonged bleeding time, maybe APTT prolongation
Factor 8 reduction
How is VWD treated?
Tranexamic acid, DDAVP, factor 8
What is antiphospholipid syndrome?
Acquired disorder characterised by a predisposition to both venous and arterial thromboses, recurrent foetal loss and thrombocytopenia.
Associated with SLE
How does antiphospholipid syndrome present
Paradoxical rise in APTT
Thrombosis
foetal loss
thrombocytopenia
other autoimmune disease, drugs
How is antiphospholipid syndrome treated?
Low dose aspirin in primary prophylaxis, warfarin for secondary
What is DIC?
In DIC, the processes of coagulation and fibrinolysis are dysregulated, and the result is widespread clotting with resultant bleeding
What are causes of DIC?
• Sepsis
• Trauma
• Malignancy
Obstetric complications
What Ix and Rx in DIC?
- low platelets
- prolonged APTT, PT, and bleeding time
- fibrin degradation products are often raised
- schistocytes due to microangiopathic haemolytic anaemia
treat caues
FFP +/- platelets
What Ix changes seen in liver coagulopathy
Causes prolonged APTT and PT due to decreased synthetic function of liver. Patients are also often vitamin K deficient
What is ITP?
Immune mediated reduction in platelet count, with antibodies directed against the glycoprotein IIb/IIIa or Ib-V-IX complex.
Kids get it post-infection, adults have more chronic disease
How does ITP present?
- may be detected incidentally following routine bloods
- symptomatic patients may present with
- petichae, purpura
- bleeding (e.g. epistaxis, mucosal)
- catastrophic bleeding (e.g. intracranial, retroperitoneal) is not a common presentation, occuring when platelets <10
Prolonged bleeding time
Platelets < 100
What are triggers for ITP/
Infection, autoimmune condition e.g. SLE, RA
Often no trigger
What is management of ITP?
Oral pred
Pooled IVIG
third will either have refractory disease or a subsequent relapse and require further and often long-term therapy such as with tPO-mimetics or splenectomy.
What is Evan’s syndrome?
ITP in association with autoimmune haemolytic anaemia (AIHA)
What is MAHA?
A type of intravascular haemolysis
What are causes of MAHA>
HUS TTP Cardiac valves Malignancy DIC Vasculitis
What Ix in MAHA?
• Anaemia • Jaundice (elevated bilirubin) • Haemoglobinuria • Elevated LDH • Elevated reticulocyte count • Negative DAT Features specific to condition (renal failure in thrombotic microangiopathy)
What are thrombotic microangiopathies?
MAHAs associated with thrombocytopenia and thrombosis.
What is TTP?
A microangiopathy in the context of severe ADAMTS13 deficiency (<10%), responsbile for breaking down VWF multimers. This causes schiscotcytes and MAHA
What are causes of TTP?
Acquired: IgG antibodies to AMAMTS13
* Idiopathic * Pregnancy * Malignancy * HIV associated * Post-infective * Drugs e.g. OCP, ciclosporin, penicillin
What are features of TTP?
- rare, typically adult females
- fever
- fluctuating neuro signs (microemboli)
- microangiopathic haemolytic anaemia
- thrombocytopenia
- renal failure
What is Rx of TTP?
• Plasma Exchange-cornerstone of acute therapy.
Immunosuppression
What is HUS?
A triad of
• acute kidney injury
• microangiopathic haemolytic anaemia
• thrombocytopenia
What are causes of HUS?
Shiga toxin from E coli
pneumococcal infection
HIV
SLE
primary HUS: complement dysregulation
What Ix in HUS?
• full blood count: anaemia, thrombocytopaenia, fragmented blood film
• U&E: acute kidney injury
• stool culture
○ looking for evidence of STEC infection
○ PCR for Shiga toxins
What Rx in HUS?
Supportive e.g fluids, transfusion, dialysis
Abx: not useful
Plasma exchange if severe
Eculizumab: C5 inhibitor MAB
