Disseminated intravascular coagulation

A 29-year-old multiparous woman suffers an antepartum haemorrhage secondary to

placental abruption and in the course of the resuscitation and subsequent emergency caesarean section receives twelve units of packed red blood cells and four units of fresh frozen plasma. The following laboratory results would be expected in acute disseminated intravascular coagulation EXCEPT which one? 

a) Reduced soluble fibrin

b) Moderate thrombocytopenia

c) Decreased factor VII levels

d) Gradual decrease in fibrinogen

e) Prolonged activated partial thromboplastin time

Answer: a

Explanation

Disseminated intravascular coagulation (DIC) is an acquired phenomenonwhereby a  precipitating event induces widespread and generalised activation of the blood clotting systems thereby producing a consumptive coagulopathy and fibrinous occlusions of the microvasculature. Precipitants are often inflammatory in nature and there is evidence that development of DIC is cytokine mediated. The pathophysiological phases are thrombin burst, anticoagulant suppression, fibrinolysis inhibition and inflammatory activation. The diagnosis ismade froma combination of an atrisk patient with positive clinical features and compatible blood tests. There is not a specific test for DIC. Intravascular coagulation is largely due to activation of the intrinsic clotting pathway, but this does not translate to specificity of laboratory tests in acute DIC where virtually all tests relevant to coagulation may be deranged. As DIC involves massive fibrin production, elevated levels of soluble fibrin would be expected although most laboratories do not routinely test for this. Note that the intuitive decrease in fibrinogen is not always seen as fibrinogen is an acute phase protein released at times of heightened inflammation, so despite massive fibrin generation, fibrinogen may be slow to fall.

Reference

Becker JU, Wira CR. Disseminated intravascular coagulation: differential diagnoses

and workup. eMedicine 10 September 2009. Online at http://emedicine.medscape.

com/article/779097-diagnosis (Accessed 30 October 2009)