Question 25.3

A 52-year-old female presents with bruising and a retroperitoneal haematoma five weeks after starting warfarin for a proximal deep vein thrombosis (DVT) with a target international normalised ratio (INR) of 2.5.

Her investigations are as follows:

Parameter

Patient Value

Adult Normal Range

Haemoglobin

122 g/L*

135 – 180

White Cell Count

10.1 x 109/L

4.0 – 11.0

Platelets

298 x 109/L

150 – 400

Prothrombin time

29.3 sec*

12.0 – 16.5

International normalised ratio (INR)

2.3*

0.9 – 1.3

Activated partial thromboplastin time (APTT)

117.0 sec*

27.0 – 38.5

Fibrinogen

3.9 g/L

2.0 – 4.0

a)    Give the likely underlying cause for this coagulation profile.    (20% marks)

b)    List two confirmatory tests.    (20% marks)
 

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College answer

Not available.

Discussion

The abnormalities are:

  • A slightly lower haemoglobin then you would expect from a normal range (though, a slightly higher haemoglobin than what you would expect from a woman with a retroperitoneal haematoma)
  • A raised prothrombin time
  • An increased INR, though totally within the therapeutic range for her DVT
  • A wildly elevated APTT

So: the extrinsic pathway is working normally (for a warfarinised lady), but the intrinsic pathway is broken. Why would that be? Naturally, you'd classify these abnormalities into two broad groups:

  • Factor deficiency
  • Anticoagulant element

Factor deficiency seems less plausible given the history. So: what anticoagulant factors can there be? Or rather; what anticoagulant factor can you think of w, which might give rise to a bleeding propensity but at the same time predispose somebody to having clots? Antiphospholipid syndrome comes to mind. 

b) 

You would want to order:

  • Antiphospholipid antibodies
  • Mixing studies

Theoretically you could also order thrombin time and reptilase time, as antiphospholipid syndrome would have a normal; TT and RT.

References

Kamal, Arif H., Ayalew Tefferi, and Rajiv K. Pruthi. "How to interpret and pursue an abnormal prothrombin time, activated partial thromboplastin time, and bleeding time in adults." Mayo Clinic Proceedings. Vol. 82. No. 7. Elsevier, 2007.

Hunt, Beverley J. "Bleeding and coagulopathies in critical care." New England Journal of Medicine 370.9 (2014): 847-859.

Miyakis, Spyridon, et al. "International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS)." Journal of Thrombosis and Haemostasis 4.2 (2006): 295-306.