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19 Cards in this Set

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What are some disorders of primary haemostasis?

Anything that affects the initial formation of a platelet plug.




1. Thrombocytopoenia


2. von Willebrand's disease


3. Disease affecting the vessel wall e.g. hereditary haemorrhagic telangiectasia, vasculitis

What are the clinical features of hereditary haemorrhagic telangiectasia?

CF: Telangiectasia and small aneurysms are found on the fingertips, face and tongue, and in the nasal passages, lung and GIT. May also develop pulmonary AVMs (must SCREEN!)


Patients can have recurrent bleeds e.g. epistaxis, or may present with iron deficiency due to occult GI bleeding.




Rx - iron therapy can allow the marrow to compensate for blood loss

What is Ehlers-Danlos disease?

Rare AD disorder caused by a defect in collagen, resulting in fragile blood vessels and organ membranes, leading to bleeding and organ rupture. Classical joint hypermobiity. Diagnosis should be considered when there is a history of bleeding but normal lab tests.

What is the cause of ITP in adults?

Usually not clear. Often there is no precipitating cause. However can be:


- HIV, hep B or C


- SLE or other autoimmune disorder


- Lymphoproliferative disorders e.g. CLL




**ITP is mediated by autoantibodies, most often directed against the platelet membrane glycoprotein IIb/IIIa, which sensitise the platelet and result in premature removal by the reticulo-endothelial system

How do you diagnose ITP in an adult?

A presumptive diagnosis of ITP can be made if there is:


- isolated thrombocytopoenia


- no underlying disorder


- normal physical exam




**Platelet antibody tests are NOT helpful - may be present without correlation


**Bone marrow biopsy may be done in over 65, to exclude myelodysplastic syndrome, or if patients are unresponsive to therapy. In ITP, bone marrow shows an increase in megakaryocaytes.

What is the treatment of ITP in adults?

Treatment is rarely given if platelets > 30 x 10^9/L




If platelets < 20:


- steroids 1 - 2 mg/kg daily until count > 50 OR


IV IgG can be used if there is a clinically more severe presentation, or patient is intolerant of steroids, or non-response to steroids after 4 weeks.




General measures may include:


- treatment of hypertension


- cessation of NSAIDs


- hormonal treatment for menorrhagia


- gastritis treatment and prevention

What is the management approach for patients with refractory ITP?

If asymptomatic and platelets > 50, no additional treatment needed.Splenectomy is considered in patients with platelets 20 - 50, after which 85% respond.10 - 20% are truly refractory, meaning symptomatic with platelets < 20. Need: re-evaluation of diagnosis. Can trial treatment with cyclophosphamide, azathioprine, thrombomimetics

What should be done before splenectomy?

Bone marrow to ensure diagnosis correct




Vaccinate! - at high risk of infection with encapsulated bacteria post-splenectomy


- pneumococcal


- h. influenzae


- meningococcal


Repeat immunisations


- yearly flu


- pneumococcal every 5 years

How does IVIG work in treatment of ITP?

IVIG blocks antibody receptors on reticulo-endothelial cells, thereby preventing platelet destruction

Which congenital bleeding disorders are X-linked?

Haemophilia A (VIII) and B (IX)




The following, on the contrary, are autosomal:


- vWD


- factor II, V, VII, X, XI and XIII deficiencies


- combined II, VII, IX, X deficiencies


- Hypofibrinogenaemia

What are the roles of von Willebrand's factor?

- Forms bridges between platelets and subendothelial components, allowing platelets to adhere to damaged vessel walls.


- Stabilises factor VIII in the plasma and protects it from proteolysis (deficiency of vWD lowers factor VIII)

What is the most common inherited bleeding disorder?

Von Willebrand's disease

What is the most common congenital factor deficiency?

Haemophilia A (factor VIII deficiency).




This is X-linked, so all daughters of haemophiliacs are obligate carriers, and there is a 1 in 4 chance of each pregnancy resulting in the birth of an affectd male baby, a normal male baby, a carrier female, or a normal female. Female carriers may have reduced factor VIII levels and a mild bleeding disorder because of random inactivation of their normal X-chromosome in the developing fetus (lyonisation).

What are the clinical features of haemophilia A?

The extent and patterns of bleeding are closely related to residual factor VIII levels. Patients with severe haemophilia (< 1% normal factor VII levels) present with spontaneous bleeding into skin, muscle and joints. Also sometimes retroperitoneal and intracranial bleeding. The major morbidity of recurrent bleeding in severe haemophilia is musculoskeletal. Bleeding is into large joints, especially knees, elbows, ankles and hips. Muscle haematomas are also characteristic, most commonly in the calf and psoas muscles.


Recurrent bleeding into joints leads to synovial hypertrophy, destruction of the cartilage and secondary osteoarthrosis.

What is the management of haemophilia A?

- IV infusion of VIII concentrate (patients can sometimes treat themselves at home) [NB: ~20% patients can form antibodies to VIII, making this ineffective]


- bed rest or splint to reduce bleeding


- DDAVP (0.3 ug/kg) is also used to raise vWF and factor VIII levels (need to monitor for water retention following use of this)

What is the difference between types 1 - 3 of vWD?

Types 1 and 3 are quantitative: decreased levels of vWF


Type 2 is qualitative: vWF molecules are functionally abnormal

What is the inheritance pattern of vWD?

It is USUALLY inherited as an autosomal dominant disease, except for type 2N and type 3, which are recessive.


There is variable penetrance, so family members can have very different presentations.

What are the clinical features of vWD?

- haemorrhagic manifestations e.g. superficial bruising, epistaxis, menorrhagia, GI bleeding


- excessive haemorrhage may only be observed after trauma or surgery (bleeding episodes are much less common than in haemophilia)

What is the management for vWD?

- many episodes of mild haemorrhage can be successfully treated by local means or with DDAVP (which raises the vWF level, resulting in a 2' increase in factor VIII)


- Tranexamic acid may be useful in mucosal bleeding