Haematology 4 Flashcards
What is chronic ITP?
• In 20% of children- the platelet count remains low 6 months after diagnosis
Mainly supportive treatment
rituximab, a monoclonal antibody directed against B lymphocyte, newer agents such as thrombopoietic growth factors
Splenectomy for drug failure
Regular screening for SLE
What is von willebrand disease?
results from either a quantitative or qualitative deficiency in von Willebrand factor- responsible for platelet adhesion and as a carrier protein for factor VIII
Usually dominant inheritance
causes a defective plug formation and since vWF is a carrier protein for factor eight, patients with vWD also are deficient for this factor
Commonest subtype is 1
What are the clinical features of Von Willebrand disease?
o Bruising
o Prolonged bleeding after surgery
o Mucosal bleeding
o Spontaneous soft tissue bleeding is uncommon.
What is the management for Von Willebrand disease?
DDAVP- which causes secretion of both factor eight and vWF into the plasma
Use in caution under 1- hyponatraemia and seizures if fluid intake is not adequate
If more severe treat with plasma derived factor VIII
Im injections, aspirin and NSAIDs should be avoided
What are the acquired disorders of coagulation?
o Haemorrhagic disease of the newborn- vitamin K deficiency
o Liver disease
o ITP
o DIC
o Inadequate intake, malabsorption or vitamin K antagonists can all be a cause.
How do you differentiate between different bleeding disorders?
o Neonate – 20% of haemophilias present here
o Toddler – haemophilias may present when starting to walk
o Adolescent – vWD with menorrhagia Family history
• Family history- if all boys then suggests haemophilia
• Bleeding history- if bleeding is ok in some situations then it suggests a bleeding tendency rather than an inherited disorder
• Drug history
• Pattern of bleeding
o Mucous membranes and skin, platelet disorders or vWD
o Bleeding into muscles or joints, haemophilia
o Scarring and delayed haemorrhage- suggestive of disorders of connective tissue
What are the types of haemophilia?
commonest severe inherited coagulation disorders
Both X-linked recessive
• In haemophilia A- there is a FVIII deficiency, it has a frequency of 1 in 5000 male births
• In haemophilia B- there is a FIX deficiency, it has a frequency of 1 in 30,000 male births
What is the management for haemophilia?
• Prompt IV infusion whenever there is any bleeding of recombinant FVIII/FIX
raising the circulating level to 30% of normal is sufficient to treat minor bleeds and simply joint bleeds
major surgery or life-threatening bleeds require the level to be raised to 100% and then maintained at 30-50% for up to 2 weeks to prevent secondary haemorrhage, this can only be achieved by regular infusion of factor concentrate (FVIII – 8-12hrs & FIX – 12-24hrs, or my continuous infusion) and by closely monitoring plasma levels
• Parents are usually taught to give replacement therapy at home when the child is 2-3yrs of age and many children are able to administer their own treatment from 7-8yrs
What is the prophylactic management for haemophilia?
- Prophylactic FVIII is given to all children with severe haemophilia A to further reduce the risk of chronic joint damage by raising the baseline level about 2%
- Primary prophylaxis usually begins at age 2-3yrs- is given 2-3 times per week, if peripheral venous access is poor, a central venous access device (eg. Portacath) may be required, prophylaxis has been shown to results in better joint function in adult life, similarly, patients with severe haemophilia B are usually given prophylactic FIX
What is the other management for haemophilia A?
Desmopressin (DDAVP) may allow mild haemophilia A to be managed without the use of blood products, it is given by infusion and stimulates endogenous release of FVIII:C and von Willebrand factor (vWF)- ineffective in B
Which conditions require a splenectomy?
o Hereditary spherocytosis
o Lymphoma
o Idiopathic thrombocytopenic purpura (IPT)
• While rare, trauma to the spleen with uncontrolled bleeding can create a situation where emergency spleen removal is necessary
Which immunisations must be given prior to a splenectomy?
o Pneumococcus o Hib o Meningococcus o Influenza. Low dose antibiotics are needed for life after the operation High risk of developing malaria
What is the pathophysiology of DIC?
A disorder characterised by coagulation pathway activation leading to diffuse fibrin deposition in the microvasculature and consumption of coagulation factors and platelets
• The commonest causes of activation of coagulation are severe sepsis or shock due to circulatory collapse
When should DIC be suspected?
o Thrombocytopenia o Prolonged prothrombin time (PT) o Prolonged APTT o Low fibrinogen o Raised fibrinogen degradation products o D-dimers o Microangiopathic haemolytic anaemia Marken reduction in naturally occurring anti-coagulants, proteins C and S and anti-thrombin
What is the management for DIC?
treat the underlying causes while still providing intensive care
supportive care may be provided with FFP (to replace clotting factors), cryoprecipitate and platelets
anti-thrombin and protein C concentrates have been used, particularly in severe meningococcal septicaemia with purpura fulminans- the use of heparin remains controversial
