Disseminated Intravascular Coagulation

Question 1

What is DIC?

Answer 1

a disorder of the clotting cascade that can complicate a serious illness.

Question 2

What are the 2 forms of DIC?

Answer 2

Acute overt form where there is bleeding + depletion of platelets + clotting factors
Chronic non-overt form where thromboembolism is accompanied by generalised activation of the coagulation system

Question 3

List 9 causes of DIC

Answer 3

Infection: esp. GRAM-NEGATIVE sepsis  
Obstetric Complications 
Malignancy 
Severe trauma or surgery 
Haemolytic transfusion reaction
Burns
Severe liver disease
Aortic aneurysms
Pancreatitis

Question 4

Describe the epidemiology of DIC

Answer 4

Seen in any severely ill patient

Question 5

List 3 symptoms of DIC

Answer 5

Symptoms of underlying disease
Confusion
Dyspnoea

Question 6

List 3 signs of DIC

Answer 6

Signs of underlying disease
Fever
Shock (hypotension, tachycardia)

Question 7

List 7 signs of acute DIC

Answer 7

Petechiae, purpura, ecchymoses  
Epistaxis  
Mucosal bleeding  
Overt haemorrhage  
Signs of end organ damage  
Respiratory distress  
Oliguria due to renal failure

Question 8

Give 2 signs of chronic DIC

Answer 8

Signs of deep vein + arterial thrombosis or embolism

Superficial venous thrombosis

Question 9

What bloods would be seen in DIC?

Answer 9

Low platelets  
Low Hb  
High APTT/ PT 
Low fibrinogen 
High fibrin degradation products  
High D-dimers

Question 10

What would be seen on blood film in DIC?

Answer 10

Schistocytes

Question 11

Describe the pathophysiology of acute DIC

Answer 11

Endothelial damage + release of procoagulant substances (e.g. tissue factor) lead to activation of coagulation
Causes explosive thrombin generation, which depletes clotting factors + platelets, whilst also activating the fibrinolytic system
Leads to bleeding in the subcutaneous tissues, skin + mucous membranes
Occlusion of blood vessels by fibrin in the microcirculation leads to MAHA + ischaemic organ damage

Question 12

Describe the pathophysiology of chronic DIC

Answer 12

IDENTICAL process to acute DI
Happens at a slower rate with time for compensatory responses
The compensatory responses diminish the likelihood of bleeding but give rise to hypercoagulable states + thrombosis can occur

Question 13

What 4 obstetric complications can cause DIC?

Answer 13

Missed miscarriage (foetus dies but body doesn’t realise + placenta continues to release hormones)
Severe pre-eclampsia
Placental abruption (separation of placenta from wall of the uterus during pregnancy)
Amniotic emboli

Question 14

Which malignancies cause acute DIC? Which cause chronic?

Answer 14

Acute promyelocytic leukaemia: ACUTE DIC

Lung, breast + GI malignancy: CHRONIC DIC