A girl with factor V leiden presented with two episodes of loss of consciousness.

The losses of consciousness occurred while she was in bed at around 8am, and neither episode was witnessed. There were no warning signs. There was no chest pain, palpitations, shortness of breath or sweats. The first episode probably lasted three to five minutes according to the patient (using clocks in the room) and she felt very tired afterwards. The second collapse happened about 20 minutes later and was similar in nature. There was nothing suggestive of seizure activity.

A pregnancy test was positive. She thinks she may have miscarried a few days before based on copious PV bleeding, but was not sure.

After appropriate investigations, no cardiac or neurological pointers were found.

The post-take ward round planned to send her home after PE was ruled out.

Going back to my post on the 12 causes of syncope, PE was the only serious cause left to rule out.

At this point, we actually had enough information to discharge her with full medical justification, but we did not realise this at the time and carried on the work up for PE. Can you see what we had overlooked?

The fact that she may have been pregnant made investigations a bit tricky. CTPAs are avoided in pregnancy as much as possible, and half dose V/Q scans are considered a necessary evil in selected cases. A miscarriage seemed likely, but it was difficult to be sure what her current pregnancy status was. Her Well’s score was 0, but then again the Well’s score does not take into account thrombophilias. Is this a high risk or low risk pretest probability? In any case if she were pregnant, the d-dimer would be raised. Was a d-dimer justified in this scenario?

Interestingly, Factor V Leiden poses a paradox, as it causes an increased risk of DVT but not pulmonary embolism. Go figure.

An early pregnancy assessment unit ultrasound was done. The endometrium of the uterus was thin and no foetus was visible, which all but ruled out a normal pregnancy.

The patient’s consultant had long since gone home, so I spoke to the on call consultant.

This consultant said something which has stuck with me.

“Surely if it were a massive PE leading to a collapse, she would be periarrest?”

“Oh yes.”

There are four severities of PE:

1. Cardiac arrest
2. Massive PE (BP<90mmHg or drop of 40mmHg for 15 minutes)
3. Submassive PE (signs of right ventricle strain/failure)
4. Non massive PE (everything else)

To have a loss of cerebral perfusion secondary to a PE, you would have to be at least a massive PE. There is no way the patient would be walking and talking.

Had anyone thought of this at the start, the patient may have been discharged during the day.

This episode inspired me to make a podcast on PE management with a friend, in line with the BTS guidance.

[Edit: 1/10/2012: I have added video bits to the podcast]