A patient with a prolonged activated partial thromboplastin time and a deep intracerebral haemorrhage

Abstract

We report on a 57-year-old woman with a pontine haemorrhage and an extremely prolonged activated partial thromboplastin time (aPTT) of more than 240 s, suggestive of a coagulation disorder. Given the location of the haemorrhage, which is associated with a high mortality rate, recombinant factor VIIa was administered, although not all necessary laboratory analyses could be performed at that time. In our case, a deficiency of factor XII was found, which is not associated with an increased bleeding risk. In an acute setting, evaluation of a prolonged aPTT may cause diagnostic and therapeutic challenges, in particular in situations where additional laboratory investigations may not be readily available.

Keywords: Factor XII deficiency; Intracerebral haemorrhage; Mixing studies; Partial thromboplastin time.

Fig. 1

A CT scan (a) and a gradient echo sequence MRI scan (b) with a small left paramedian pontine haemorrhage.

Fig. 2

Coagulation mechanisms as measured by PT and aPTT (left panel) and the principle of the mixing studies (right panel). In case of a factor deficiency, mixing of the patient plasma with normal pool plasma will result in the correction of the prolonged aPTT since a coagulation factor activity of 50% yields a normal (nonprolonged) aPTT (upper right panel). In case of a coagulation factor inhibitor, mixing of the patient plasma with normal plasma will not result in the correction of the aPTT since the inhibiting antibodies will also inhibit the coagulation factors in the plasma of the normal plasma (lower right panel).