Clinical question: Can a TIA cause syncope?

Gday readers – today I am crowdsourcing an answer to a clinical conundrum.  Sorry no answers – I want to know what you think.

I have been giving a particular tutorial to my trainees for a while now – it is a sort of “choose your own adventure” diagnostic puzzle.

I split my class into 2 groups and ask them to choose a serious of diagnostic “decision points” in order to try and work out what is going on.

It starts with a pair of patients presenting by ambulance post collapse / syncope and now fully conscious on arrival to the ED

–  the patient has a normal BSL from the ambulance and has no focal neurology on arrival.

–  witnesses report a simple collapse, no seizure activity

It is usually a lot of fun, but every time I play this game one of the teams inevitably comes to the conclusion that a TIA is top of their diagnostic probability.

Now, I have done this enough times to be sure that this is more than just chance – there must be something to it.

So here are my questions to you smart folk out there:

Q1:  Have you ever seen a patient with syncope which was due to an ischemic / embolic TIA?

Q2:  In theory – can an embolic TIA cause syncope, and if so –

Q3:  Where does it have to lodge in the cerebral vasculature?

Q4: is this a common belief amongst doctors – did I miss something in Med School?  Is TIA likely in a patient with syncope?


PLease educate me – can TIAs cause syncope?



PS;  Here are some of the twitter comments coming in over the past 24 hours.  Seems  most say no, but never say never.  The old Davidson paper cited from  Clin. Cardiology 1991 is a bit soft for my reading – they called anything where they couldn’t find an alternate diagnosis a TIA – which is a long bow to draw – after all vagally-mediated syncope is pretty common and leaves no trace on subsequent Ix usually.  And this was before much MRI and MRA etc.  Though I think it is fair to say if you work up the patient and they have bilateral 90+% carotid stenoses then you might want to consider a vascular cause over a primary cardiac problem!

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