List five likely causes for the following coagulation profile:

Parameter

Result

Normal Range

PT

35.4 secs*

12.0 – 15.0

INR

3.5*

0.8 – 1.1

APTT

>170.0 secs*

25.0 – 37.0

Fibrinogen

0.9 G/L*

2.20 – 4.30

 

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College Answer

  • DIC
  • Primary fibrinolysis 
  • Dilutional coagulopathy from massive transfusion
  • Post thrombolysis 
  • Snake bite

Discussion

All the coagulation parameters are deranged.

Of the differentials presented by the college, the unfamiliar ones are primary fibrinolysis and snake bite.

Snake bite can be pro or anti-coagulant. One might be unlucky enough to be bitten by Russell's Viper.

"Primary fibrinolysis" refers to some sort of a normal process of clot breakdown. It occurs when massive amounts of some sort of plasminogen activator enter the circulation - for instance, after trauma. The distinction between this and DIC is the absence of fibrin deposition. Platelet count should be normal in primary fibrinolysis, as they are not being consumed.

One might ask, "how is this not warfarin toxicity", but the low fibrinogen does not favour this differential. It's hard to say that it completely excludes it, but one does not normally expect such a low fibrinogen level in warfarin overdose. This case report by Card et al (2014) had a normal fibrinogen in a patient who ingested an amount of difenacoum described as "massive". Lip et al (1995) did not find any low fibrinogen levels among long-term warfarinised patients.

 

References

References

White, Julian. "Snake venoms and coagulopathy." Toxicon 45.8 (2005): 951-967.

Kashuk, Jeffry L., et al. "Primary fibrinolysis is integral in the pathogenesis of the acute coagulopathy of trauma." Annals of surgery 252.3 (2010): 434-444.

Card, David John, et al. "Case Report: Superwarfarin poisoning and its management.BMJ case reports 2014 (2014).  

Lip, Gregory YH, et al. "Effects of warfarin therapy on plasma fibrinogen, von Willebrand factor, and fibrin D-dimer in left ventricular dysfunction secondary to coronary artery disease with and without aneurysms.American Journal of Cardiology76.7 (1995): 453-458.