Bleeding Flashcards
pathophysiology of ITP
immune system makes antibodies against platelets… resulting in destruction of platelets
mechanism of rituximab
monoclonal antibody against B cells
management of ITP (4)
- IVIG
- steroids
- Rituximab
- Splenectomy
in ITP what complex on platelets are attacked?
GPIIb/IIIa complex
blood test findings in ITP
- raised megakaryocytes in bone marrow
- antiplatelet autoantibodies
1st line trx ITP (2)
- Oral corticosteroids
- IVIG
non immune causes of destruction of platelets
- HUS
- TTP
medications that destroy platelets
- Methotrexate
- Isotretinoin
- PPI
- Antihistamines
- Na Valporate
condition where tiny blood clots form throughout the small vessels of the body
TTP - thrombotic thromocytopenic purpura
deficiency in which protein in ITP?
ADAMTS13
role of ADAMTS13 usually?
this protein inactivates vWF & reduces platelet aggregation to vessel walls … therefore reducing clot formation
3 poss treatments for ITP
- Rituximab
- Steroids
- Plasma exchange
4 symptoms/signs of ITP
- florid purpura
- fever
- haemolytic anaemia
- fluc cerebral dysfunction
name of the heparin induced antibodies that specifically target a protein on platelets?
anti-PF4
4 acquired coagulation disorders
- liver dysfunction
- anticoagulant medications
- DIC
- Vit K def
congenital coagulation disorders (2)
- vWF disease
- Haemophilia A & B
what happens in platelet plug formation?
Platelets aggregate to form a platelet plug that temp seals the break in the vessel wall
3 tings released that i) enhance vascular spasm ii) cause more platelets to aggregate to area
- Thromboxane A2
- ADP
- Serotonin
what activates platelet plug formation
vWF
which pathway involves F7
extrinsic pathway
what happens in extrinsic pathway?
TF + F7 –> TF-F7a
which activates FX + FIX
Vitamin K dependant coagulation factors?
F2,7,9,10 and Protein C & S
inheritance of Haemophilia A & B
X linked recessive
F8 deficiency
Haemophilia A
Haemophilia B - deficiency of?
F9
what is Haemophilia B also known as?
Christmas disease
what is haemoarthrosis
spontaneous bleeding into joints
half life of F8
8 hours
management of acute episodes of bleeding in haemophilia?
- IV infusions (F8/9)
- Desmopressin
- Tranexamic acid
desmopressin affect on vWF
stimulated the release of von Willebrand Factor
most common inherited cause fo abnormal bleeding?
Von Willebrand disease
vWD inheritance?
type 1&2 = autosomal dominant
type 3 = recessive
type 1 vWD caused by?
quantitative deficiency of vWF
type 3 vWD caused by?
complete deficiency of vWF
type 2a & b vWD caused by?
type 2a - reduced/abnormal vWF
type 2b - abnormal vWF
role of vWF (2)
- promotes platelet adhesion to damaged endothelium
- carrier molecule for F8
avoid desmopressin in which vWD
type 2b
which vWD can result in thrombocytopenia
Type 2b
what is virchows triad
3 factors thought to contirbute to thrombosis:
- blood flow stasis
- endothelial injury
- hypercoagulability
mechanism of aspirin
irreversibly inhibits cyclo-oxygenase
mechanism of clopidogrel
blocks platelet aggregation and prolongs platelet survival by inhibiting the binding of ADP to its platelet receptor
differentials of unilateral swollen painful calf?
- DVT
- Cellulitis
- Ruptured bakers cyst
- muscle haematoma
what is Homans sign?
calf tenderness worse on dorsiflexion of ankle
calf circumferences in DVT?
> 3 cm compared to unaffected leg when measured 10cm from tibial tuberosity
what is a PE called when SBP < 100 mmHg
Massive PE
PE ECG changes
- Sinus tachycardia
- S1Q3T3
management options for women with vWD with heavy periods (5)
- COCP
- mirena coil
- tranexamic acid
- mefanamic acid
- norethisterone
