DIC Flashcards
When does acute DIC occur
- Acute DIC occurs when large amounts of tissue factor are released over a short duration, not allowing for compensatory increase in platelets/ factors
Profound bleeding from lines, catheters, surgical sites
What is DIC
Widespread acitvation of intravascular coagulation in small and medium vessles not localised
Inhibiton of fibrinolysis and depletion in physiological anticaogulants
MOA of DIC
Trigger-> formation blood clots in small vessles
Depletion of clotting factors and platelets in clots -> increased bleeding risk
Breakdown of clots inhibited - inhibited fibrinolysis
BOTH CLOTTING AND BLEEDING
Conditions causing DIC
Create or release prothrombotic factors
Sepsis
Cancer - APL, disseminated adenocarcinoma
Obstetric causes eg amniotic fluid embolism
Shock
Extensive surgery
How do diseases cause DIC
Sepsis - LPS on surface of gram negative bacteria thrombotic
Cancer - tissue factor on tumour cells
Obstetric - eg reatined placental products, placental disrution -> tissue factors enter maternal circulation
Shock - ischaemic injury -> exression of tssue factor intravascuarly
DIC outcomes
Higher rates of mortality and morbidity than underlying conditions
Lab tests in DIC
Prolonged APTT and PT
Lowered fibrinogen and platelets
V high D-dimer
Why is it important to ask for Clauss fribrinogen in DIC or major haemorrhage
Abnormal PT/APTT means inaccurate fibrinogen derived from clotting screen
Presenting features of DIC
Sick patient
Bleeding from venepuncture sites
New VTE rarely
Organ dysfunction due to microvascular thrombus
What score use in DIC
ISTH
Parameters for DIC score
Platelet count
D-dimer
PTT
Fibringoen
What score indicates DIC in ISTH
> 5
3-4 doesnt rule out - eveolving syndrome
Treating DIC
Treat underlying cause
Mainatin haemosatsis
Basic treatment DIC
IV vit K replacement support production of clotting factors
Maintain physiological pH and Ca levels
Maintain body temp
When replace blood in DIC
Severe bleeding
What give in severe bleeding in DIC
1 pool of platelets if <75
2 pools cryoprecipitate if fibrinogen <1.5
4 U FFP to replace coag factors and natural anticoags
What causes DIC
Massive activation of clotting cascade due to TF release, overwhelm antithrombotic pathways
What causes bleeding in DIC
- Consumption of platelets and factors, due to secondary hyperactivation of fibrinolysis, leads to bleeding
What anaemia is seen in DIC
- Shearing of red blood cells over intravascular fibrin strands leads to microangiopathic haemolytic anaemia (MAHA)
Less common causes DIC
paroxysmal nocturnal haematuria, acute haemolytic transfusion reactions, purpura fulminans, catastrophic antiphospholipid syndrome, hepatic failure, aortic aneurysm, hyperthermia, giant haemangiomas, peritoneal venous shunts, snake venoms, amphetamines
Chronic DIC cause
Sall amounts TF released over time - compensatory increase in platelet and factors but also build up of procagulants
Asymptomatic or microvascular, arterial or venous thrombi -> end organ damage
Differnetials for DIC
MAHA: TTP/HUS, HELLP, vasculitis, scleroderma, hypertensive crisis, etc. (normal coagulation studies)
Liver failure (can coexist with DIC)
HIT (normal coagulation studies)
Baseline investigations DIC
FBC, blood film, LDH, bilirubin, haptoglobin, reticulocyte count, INR, APTT, fibrinogen, liver enzymes, creatinine
β-HCG, septic work up as appropriate for clinical situation
When is heparin used in DIC
management of thrombosis in patients with chronic DIC.
