02 - Bleeding , 70 - rectal bleeding Flashcards
What are platelets called? What inhibites them in an intact endothelium ?
Which cell is their precursor?
Life span?
Activated by?
Do they need to be crossmatched before transfusion?
thrombocytes Nitric Oxide Megakaryocytes thrombin and exposed endothelial collagen 8 days No
Thrombocytopenia usually found when?
Causes?
Mx?
Usually silent and found on FBC
-Or bleeding esp from nose/gums
Pupura/petachae
leukemia, sepsis, Fanconi anemia, liver failure, aplastic anemia, ITP, TTP, haemolytic uraemic syndrome, DIC, drug side effects.
Treat underlying cause
Transfusion if severe
Transfusion is CI in which cause of thrombocytopenia
Thrombotic thrombocytopenic purpura
Not sure i believe this based on evidence - But keep in back of mind
key triggers of clotting cascade ? What is formed?
Endothelial injury + tissue factor
factor VII
(Cascade of protein cleavage and fibrin formation)
How does heparin work
deactivates thrombin and factor Xa
Main use of heparin? reversed with?
Treat and prevent DVT / PE
Reversed with protamine
Egs of some LWMHs? Why beneficial to heparin?
enoxaparin, dalteparin and tinzaparin
Less effective but far less side effects (thrombocytopenia and osteoporosis)
What is warfarin / how does it work?
How do you monitor?
Vit K inhibitor -> inhibits factor VII and prothrombin
INR and dietrary restrictions
Heparin / warfarin in pregnancy
heparin is ok
Eg of NOACs?
Vs warfarin
Rivaroxaban, dabigatran etc.
Just as effective as warfarin in preventing CVAs with AF.
Less bleeding events bar GI bleeds.
Are more expensive than warfarin, but you save money on bleeding events and community monitoring, so it balances out.
which enzymes are key for fibrinolysis ?
Egs of drugs? Used when?
Plasmin enzymes
Plasminogen cleaved to Plasmin via urokinase and tissue plasminogen activator.
Plasmin degrades fibrin.
MI, ischaemic stroke and PE via streptokinase and other tPas (alteplase and reteplase)
What is a major bleed? 4 stages?
When do you transfused packed cells?
50% volume in 3 hours / >150ml/min
(clinically if has lead to shock in excess of 90mmHg OR 110bpm
Like Tennis
15%, 30%, 40%, >40%
Stage 2
What blood do you transfuse? Who gets something specific?
What risk with transfusion with relation to bleeding?
O
Females <50 get Rh-ve
Dilutional coagulopathy as with lots of resus fluid and red cells dilute clotting components
Approx rise in Hb / unit of blood? What level before transfusion
1
<8
Eg causes of upper GI bleed?
What interesting fact in Mx?
mX/
PUD, varices, etc.
Different to normal major haemorrhage in that transfusions worsen outcomes (unless patient is shocked)
Use terlipressin and PPIs instead.
What is shock?
Features?
Types?
Inability to adequately maintain end organ perfusion
Low BP, high pulse, low urine, confusion, LoC, pallor, hypothermia etc.
Hypovolemic, Cardiogenic, Obstructive and Distributive.
What is DIC? Initial Mx?
Pathological activation of the clotting cascade throughout the body, usually as a response to bacterial infection (from endotoxin
Clots formed in small vessels causing organ damage whilst coagulation products are consumed, leading to severe bleeding.
Treat underlying condition Eg sepsis / obstetirc, transfusion reaction, allergies….
Transfuse platelets as bleeding will kill first
What is ITP ? Caused by? Mx?
Idiopathic thrombocytopenic purpura
Low platelet count with normal bone marrow. Diagnosis of exclusion.
May get purpuric rash / bleeding
Autoimmune response to platelet surface antigens
Conservative with steroids - can transfuse if needed
What is TTP? 5 features?
Cause?
Mx?
What main issue with Mx?
Thrombotic thrombocytopenic purpura.
fever renal failure neuro symptoms (clots interrupting blood supply to the brain), haemolytic anaemi thrombocytopenia.
Spontaneous small vessle coagulation (Eg due to preg, drugs, Ca)
Plasmapheresis and corticosteroids
Transfusion worsens coagulopathy
Haemophilia A vs B ?
Genetics?
Complications?
A is a Factor VIII deficiency.
B is a Factor IX deficiency.
Only seen in males (X-linked) two copies are not compatible with life.
Complications include haemarthrosis, internal bleeding, CVA, blood infections.
Where is vWF found?
Epithelium basement membrane
How does aspirin work? As a anticoagulative?
Clopidogrel?
More or less bleeding risk with clopidogrel?
irreversible COX inhibitor (cox 1 most) -
Prevents inflammation
Also prevents platelet aggregation via thromboxane inhibition
-Clopidogrel does this too via ADP inhibition
Less GI bleeding risk with clopidogrel
Some DDx of rectal bleeding
Haemorrhoids fissue cancer IBD Angiodysplasia Meckles Intussusception
what is meckels diverticulum?
Congenital diverticulum in small intestine. Remains of foetal vitelline duct.
What is the rule of 2s with meckels
2 feet from ileocaecal valve, 2 inches long, in 2% of population, 2 years presentation, 2 types of tissue (gastric and pancreatic)
Increased risk of what with meckels
hernias, volvulus, obstruction, intussusception
Mx of meckels
resection
