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On examination:

• Speech – normal
• HMF – normal
• Cranial nerves – normal
• UL – normal
• LL – normal

So the neurological examination has not really been that helpful, although absence of neurological signs might be useful information.

If we go back to the history, which is where most diagnostically useful information comes from, we notice that the presentation fits the 3 p’s we look for in syncope. These are :

• precipitant
• prodrome
• posture.

In this case, the patient had a precipitant – watching a gory (and presumably terrible) film, a prodrome –  nausea, and a postural element – collapse after standing.

The potential confounding elements of the history are the witness report of a”fit”. Witness reports are vital in differentiating causes of blackout but we really need a lot more detail than this to place any value on their account. What did the patient look like before the blackout? What happened during it specifically (e.g. any tonic phase, which bits of the body were jerking, was it rhythmic, did the patient make any noise before the jerking)? How long did it last for? How quickly did the patient come around? Increasingly people are aware of the value of videoing blackouts and this can be invaluable in making the diagnosis.

It is important to remember that people often jerk and twitch with vasovagal syncope (watch the video in our blackout article which shows how difficult it can be to differentiate myoclonus in syncope from seizure activity!). Similarly, urinary incontinence does not discriminate between seizure and syncope (despite what you may have been told!).

Overall, the most likely diagnosis here is vasovagal syncope.

What else might you do?

As with any blackout, the ECG is the most important investigation. This history is not particularly suggestive of cardiac syncope but there are patients with arrhythmia (long-QT, AV-block) who present with blackout. This is treatable and dangerous if not diagnosed.

Does this episode effect driving for the patient? (See page 23 of the DVLA guidance for the answer!)

There is a lot more information about blackouts here.