Bleeding disorders Flashcards
what is the basic pathogenesis behind bleeding disorders
unable to form clots to stop bleeding
ie failure of primary/secondary haemostasis
what are the 3 main factors in primary haemostasis
vascular
platelets
VWF
list heritable causes of vascular defects in primary haemostatic failure
Marfans syndrome
AD - fibrillin mutation
list acquired causes of vascular defects in primary haemostatic failure
old age - loss of collagen
scurvy - Vit C deficiency
vasculitis - HSP
what can occur to platelets in primary haemostatic failure
reduced number
reduced function
what are causes of reduced platelet count in primary haemostatic failure
reduced production: bone marrow failure
increased destruction: ITP, DIC, hypersplenism
what is another finding in bone marrow failure
pancytopaenia
what is ITP
immune thrombocytopaenic purpura
autoimmune condition attacking platelets
causes of hypersplenism
liver disease and portal hypertension
lymphoma
what are causes of reduced platelet function in primary haemostatic failure
drugs - antiplatelets, NSAIDs
renal failure
VWF deficiency/excess can result in primary haemostatic failure
deficiency
cause of VWF deficiency
AD condition
common
symptoms of primary haemostatic failure
bruising purpura muscosal bleeding: epistaxis, gums, GI, menorrhagia intracranial bleed retinal haemorrhages
what are the main categories for secondary haemostatic failure
multiple clotting factor deficiencies
single clotting factor deficiency
causes of multiple clotting factor deficiencies
liver disease - NAFLD, ALD, PBC, viral hepatitis
vit K deficiency/warfarin
complex coagulopathy - DIC
where are all coagulation factors produced
liver
which clotting factors are carboxylated by vitamin K
2,7,9,10
what are the sources of Vit K
dietary - green leafy veg
intestinal synthesis
where is vit K absorbed
proximal gut
what is needed for vit K absorption
bile salts
causes of vit K deficiency
reduced dietary intake
^ warfarin
obstructive jaundice
malabsorption
what is the action of warfarin
vit K antagonist
what is DIC
Disseminated intravascular coagulopathy
Widespread tissue damage and inflammation causes excessive and abnormal haemostasis
Formation of microvascular thrombi resulting in tissue ischaemia and end organ failure
Clots are broken down and there is more bleeding and more clots are formed
clotting factors eventually become depleted
management of DIC
platelet, plasma, cryoprecipitate transfusions
ADDRESS THE CAUSE
what investigations are useful for secondary haemostatic failure and what are the findings in multiple factor deficiency
prothrombin time
APTT
both prolonged in multiple deficiencies
list causes of DIC
sepsis
malignancy - adenocarcinomas (chronic DIC)
obstetric emergencies eg placental abruption
hypovolaemic shock
what is a cause of single protein deficiency as part of secondary haemostatic failure
haemophilia
women are affected by haemophilia, true or false
FALSE
women are carriers as the condition is X-linked
what is the inheritance of haemophilia
X linked
males affected only
define haemophilia
X-linked hereditary condition in which there is abnormal prolonged bleeding episodically at 1/few sites on each occasion
which clotting factor is deficient in haemophilia A
VIII
which clotting factor is deficient in haemophilia B
IX
which is more common haemophilia A or B
A
pathophysiology of haemophilia
loss of amplification of secondary haemostasis
PT and APTT are both very prolonged in haemophilia, true or false
FALSE
only APTT is prolonged (intrinsic pathway with factors VIII/IX)
clinical features of haemophilia
recurrent haemarthroses
recurrent soft tissue bleeds
prolonged bleeding after procedure eg dental …
what is a consequence of recurrent haemarthroses
iron is damaging to synovium and so eventually patients will need a joint replacement
management of haemophilia
intravenous factor VIII/IX every 2 days
huge undertaking for parents
