L27: Disseminated Intravascular Coagulation Flashcards
What is DIC
Complex & acquired disorder of haemostats that commences with widespread activation of blood coagulation within microcirculation and may progress to sustained fibrinolysis and haemorrhage!!!
Is DIC a bleeding or clotting disorder?
Initially a clotting disorder that leads to haemorrhage
Is DIC a primary dz?
nah –> there are triggers for it!
What are some brief examples of pathologies that can trigger DIC
Pancreatitis, tissue trauma, snake envenomation, trauma, malignant neoplasia, foetal membrane retention, tumours releasing proteases, bacteraemia, widespread vascular endothelial injury, heart worm, widespread hepatic necrosis, GDV, shock, stagnant blood flow following prolonged anaesthesia etc.
Which major mechanisms trigger DIC?
large release of TISSUE FACTOR (factor III aka thromboplastin) which activates the extrinsic coagulation system
Wide endothelial injury
G- endotoxin release
tumours releasing proteolytic enzymes
What occurs during phase 1 of DIC (compensated)
Hypercoagulability
Primary disease –> procoagulants released –> counterbalanced (antithrombin III etc.)
Clin signs= of primary disease
Why does phase 2 of DIC occur?
run out of anticoagulants!!!
ECs change to procoagulant phenotype, fibrinolysis is suppressed
What happens n DIC phase 2?
run out of anticoagulants –> congestion/ oedma/ haemorrhage –> microthrombosis
What clinical signs are evident in DIC phase 2?
coughing, in RR, cyanosis, shock, pallor, prolonged CRT, organ failure, coma
What is microangiopathic haemolytic anaemia?
fragmented trauma to circulating erythrocytes –> schistocytosis
What happens during phase 3 of DIC?
Haemorrhage!
Platelets and coagulation factors have been exhausted –> thrombocytopenia –> haemorrhage
why are systemic inflammatory responses and cytokine cascades activated in DIC?
systemic inflammatory response
Cytokine cascades
*activated coagulation factors are generally pro-inflammatory
Why do DIC animals go into shock?!
Clotting factors generate kinins e.g. bradykinin –> mass vasodilation + increased vascular permeability –> systemic hypotension
What stage of DIC is associated with the highest morbidity and mortality?
2
What post mortem lesions might you find from an animal that has died from DIC?
Microscopic thrombi in tissues,
Large volume bleeds
