Syncope query cause? Risk stratification is the aim of the game

As an FY1 when I saw syncope I saw my job as taking a nice pre, during and post history of the event and working out what the most likely cause was. This still mostly holds, but I realise the job of the A&E doctor is both less than this and yet beyond this.

I recently saw a man in his 60s present as ? head injury. He had just left the shower and felt like he was about to vomit. He then sat down on the toilet (not using the toilet but just sitting on it) and a few seconds later fainted. He was unconscious for about 20 seconds as witnessed by a family member. There was no incontinence, tongue biting or unusual movements. There was no chest pain or palpitations before the fall, and he felt fine afterwards. He may have banged his head on the radiator on the way down, but was otherwise fine and complained of no injuries.

He was being investigated for obstructive jaundice at the time.

His past medical history included Type II diabetes, a meningioma excised 5 years ago and purportedly hypertension. His medications were metformin, ramipril, simvastatin and loratidine.

Neurologically he was intact apart from a right pupil of 4mm compared to a left pupil of 3mm. There was a scar from a previous resection of a meningioma.

Cardiovascular examination was unremarkable. Postural blood pressures showed a significant drop (133/76 versus 101/74).

An ECG showed sinus bradycardia at 54.

FBC, U&Es and CRP were all unremarkable. LFTs confirmed obstructive jaundice.

Using the four groups of 3 trick, I worked through the list.

Cardiac: Arrythmia, ACS, outflow obstruction (basically aortic stenosis or HOCM)

Neurological: Seizure, stroke/TIA, raised ICP causes (especially bleeds in the acute setting)

Neurologically mediated: Vasovagal, carotid sinus hypersensitivity, cough/micturition syncope

Oddballs: (I think of these as ‘PH, P, H’): Postural Hypotension, PE, Hypoglycemia

I felt that this patient probably had a syncope related to his postural hypotension from ramipril or autonomic failure from diabtes, with an arrhythmia less likely.

The A&E registrar decided that the patient should go under the medics.

When I made the referral, I expected to be quizzed as to my likely cause for the syncope. Instead, I got asked quite simply: “What’s his risk?”

His risk of what? Of each of the causes of syncope?

“Risk…?” I said

“His risk.”

I didn’t realise what she was talking about. Was this specifically for arrhythmia?

“Well he is in sinus at 54. The ECG was otherwise unremarkable.”

“Has he got any cardiac failure?”

Ah, getting warmer. This is the risk for arrhythmia/cardiac causes.

“Not really, though he is a diabetic with hypertension so has a decent ischaemic risk.”

“Fine”  she said in a voice that was anything but fine with it.

I decided to find out what this risk was. It turns out there are scoring systems for predicted the risk of a cardiac cause for the syncope in the ED. You can use the ROSE score  but even this isn’t fully accepted. It places emphasis on the BNP, which is quite expensive and not often measured in the ED.

Another approach to picking out the patients at high risk of cardiac syncope is to use the patient’s age to mentally risk stratify them:

pre test syncope causes

You can see how past the age of 60 non simple causes become a lot more prevalent. In fact, the cardiac causes of syncope have a bimodal distribution; the smaller peak is young people with inherited cardiac conditions and the larger peak is people over 65.

You can then use the ESC guidelines to get an idea of the risk for a cardiac cause. This could then inform the medical team about the likelihood that there is a cardiac cause worthy of further investigation.

risk

It’s a change from how I used to think about things a year ago, where I was focused on making the diagnosis as accurately as possible. Now I realise the job is to work out where the patient is heading next, even if we cannot quite label the condition at the moment.

By Viral Thakerar

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