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what is HHT?
hereditary haemorrhagic telangectasia
genetics of HHT?
- autosomal dominant
- mutation in endothelial receptor for
what is TGF-beta?
what is the clinical picture of HHT?
- small aneurysms: fingers, face, lungs, GI
- PAVM -> arterial hypoxaemia
- recurrent bleeds -> Fe deficiency anaemia
management of HHT?
- ablate PAVM
- iron supplements
- laster therapy for GI bleeds
what is ehlers-danlos 4 disease?
- vascular defect in collagen III
- -> fragile endothelium and organ membranes
how common is ehlers danlos?
1/100 000 rare
what is scurvy?
vit C deficiency
what are the consequences of scurvy?
- perifollicular and petechial haemorrhage
- subperiosteal bleeding
what is glanzmann's syndrome?
what cells affected
- due to reduced membrane glycoproteins
- autosomal recessive
treatment for glanzmann's syndrome?
name some antifibrinolytics?
- transexamic acid
- recombinant VIIa
what is ITP?
idiopathic thrombocytopenic purpura
what happens in ITP?
- autoAbs vs PLT membrane glycoprotein IIb/IIIa
- -> premature removal by reticulo-endothelial system
clinical effect of ITP?
sex more prone to getting ITP?
after 65yrs, what does ITP predispose to?
- B cell malignancy
- connective tissue disorder
when does a patient need treatment for ITP?
ie how low does the PLT count need to be...
why do you give pred for people with ITP who are spontaneously bleeding?
- to stop antibody production
- to reduce the activity of reticuloendothelial cells in removing the PLTs
haemophilia A lacks which factor?
haemophilia B lacks which factor?
what is the commonest cause of coagulation problems?
talk about factor VIII?
- made by liver and endothelium
- 12hr half life
- carried by vWF
one in how many people have haemophilia A
genetics of haemophilia?
- X linked
- can screen via CVS
why can female carriers of a recessive haemophilia gene have lower factor VIII/IX?
random inactivation of normal X (lyonisation)
what is the cause of secondary arthritis in haemophilia?
spontaneous bleeding into joints
management for haemophilia?
- patient can keep factor VIII/IX at home in fridge in case of bleeding
- DDAVP for VIII
why can DDAVP be used for treating haemophilia A?
- because it increases the release of vWF
- which means the limited factor VIII hangs around longer
what is the risk of factor VIII treatment for haemophilia A?
developing anti-factor VIII autoAbs
could then give activated factor VII
what kind of infections does a lack of factor VIII leave you prone to?
- viral eg
- HIV, CMV, vCJD, HBV
which is more common:
haemophilia A or B?
what happens in von willebrand disease?
- autosomal dominant chromosome 12 mutation
- impaired vWF so less factor VIII available
- so PLT can't bridge to the exposed collage in torn vessel wall
treatment for von willebrand disease?
- transexamic acid for mucosal bleeding
- factor VIII
infertility is linked to a problem with which clotting factor?
what clotting factors does the liver produce?
- 5, 7, 8, 9, 10, 11
- prothrombin (2)
how does liver disease affect clotting?
- decreased factors
- decreased plasminogen clearence
how does hypersplenism affect clotting?
how does cholestatic jaundice affect clotting factors?
- it reduces vit K absorption
- less factors 2, 7, 9, 10
how does kidney failure affect clotting?
- high urea
- increases risk of bleeding
- prolonged bleeding time