-
what is HHT?
hereditary haemorrhagic telangectasia
-
genetics of HHT?
- autosomal dominant
- mutation in endothelial receptor for
- TFG-beta
-
what is TGF-beta?
angiogenic cytokine
-
what is the clinical picture of HHT?
- telangectasia
- 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
- brusing
- subperiosteal bleeding
-
what is glanzmann's syndrome?
genetics
what cells affected
how
- thromboasthenia
- due to reduced membrane glycoproteins
- autosomal recessive
-
treatment for glanzmann's syndrome?
antifibrinolytics
-
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?
- bleeding
- bruising
- menorrhagia
-
sex more prone to getting ITP?
women
-
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...
<30
-
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?
VIII
-
haemophilia B lacks which factor?
IX
-
what is the commonest cause of coagulation problems?
haemophilia A
-
talk about factor VIII?
- made by liver and endothelium
- 12hr half life
- carried by vWF
-
one in how many people have haemophilia A
10 000
-
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
- physio
- 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?
A
-
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?
- DDAVP
- transexamic acid for mucosal bleeding
- factor VIII
-
infertility is linked to a problem with which clotting factor?
VIII
-
what clotting factors does the liver produce?
- 5, 7, 8, 9, 10, 11
- prothrombin (2)
- fibrinogen
-
how does liver disease affect clotting?
- decreased factors
- decreased plasminogen clearence
decreased clotting
-
how does hypersplenism affect clotting?
thrombocyotpenia
-
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
|
|
