9. Disorders of Haemostasis Flashcards
4 things causing defective haemostasis
- abnormalities in vasc system
- thrombocytopenia
- thrombocytopathy (disordered platelet function)
- defective coagulation
what is most sever disorder
coagulation disorder
bleeding can be into joints and soft tissues
characteristics of vascular bleeding disorders
- easy bruising
- spontaneous bleeding from small vessels
main type of inherited vascular disorder
hereditary harmorrhagic telangiectasia (HHT)
what type of genetic defect is HHT
autosomal dominant
so effects men and women equally
what happens in people with HHT
arterovenous malformations
(connection between arteries and veins will bypass the capillaries)
symptoms of HHT
- telangiectases on nose, tongue, lips = vry common)
- nosebleeds
- GI blood loss (bit more rare) = can lead to chronic iron deficiency
when and what treatment used for HHT
if small blood loss, then no intervention needed
otherwise:
- embolisation = introducing artificial blood clot
- laser treatment to fuse vessels
- tranexamic acid
3 types of vascular purpura
- purpura simplex
- senile purpura
- infection associated purpura
when can infection associated purpura be lethal
whne in unvaccinated individuals
viruses like measles can damage blood vessels around brain or organs
thrombocytopenia meaning
deficiency in plateley numbers
lower than 150x10^9/L
3 main causes of thrombocytopenia
- failure of platelet production (most common)
- increased destruction of platelets
- sequesteration of platelets
what might cause failure on platelet productio
usually bone marrow failure
- aplastic anaemia
or
- leukemia
(2 things that can cause the bone marrow failure)
- drug/viral toxicity
How can we diagnose thrombocytopenia
- clinical history
- peripheral blood count
- blood film
- bone marrow exam
main cause of increased destruction of platelets
autoantibodies attaching to platelet surface
(so some kind of autoimmune disease)