Swallow and Vaso-Bagel Syncope As Uncommon Causes of Passing Out.

So I got asked to consult on a patient admitted with swallow syncope. I found that fascinating.  Swallow syncope?  I'd never heard of that before.  Syncope is one of the most common admitting diagnoses I do.  As  internists, we often do way too much in the evaluation of syncope.

Syncope is another word for passing out due to a global loss of perfusion and oxygenation to the brain.  Many studies have shown the very low yield of doing extensive evaluations for syncope.   A lot of the work up is based on old habits and fear of the unknown.  Hospitalists, internists, cardiologists and other subspecialists will often order a vast array of testing for syncope, much of which is rarely diagnostic.  That allows doctors to tell patients everything looks normal.  If anything, it gives patients some peace of mind.

I find the shotgun approach to syncope to be expensive and low yield.  Shotgun medicine is one reason why medical care is so expensive.  This approach is not evidence based.  It's often fear driven. We need to let our history and physical guide us in our evaluation of syncope.   Swallow syncope is one situation where listening closely to what the patient has to say makes all the difference in the world.

Was there a postictal state of confusion?  Was there loss of bowel or bladder dysfunction or a tongue laceration.  If not, doing an EEG is rarely appropriate.  Was there a murmur or a  history of cardiac disease, cardia arrhythmia, valvular disease  or an abnormal EKG?  If the answers are no, a cardiac echo is unlikely to offer you any explanation for syncope. Even telemetry is of low yield in a patient with a normal looking EKG and cardiac exam. Does their carotid massage induce a bradycardic response?  That's an often forgotten initial  physical exam technique that can be used to evaluate for vagal tone.   

As for doing carotid dopplers, these are often  a waste of time, money and resources in the evaluation of syncope.  To pass out, one must experience global hypoxemia.  That means to have carotid obstruction as a cause of syncope, one must simultaneously experience bilateral carotid occlusive disease.  That never happens.  Doing carotid dopplers in a patient with syncope is rarely appropriate.  If physicians are evaluating patients with syncope in the setting of stroke symptoms, carotid duplex dopplers are appropriate.   For syncope without stroke symptoms,  carotid dopplers just aren't indicated.

Sometimes patients with a  pulmonary embolism present with syncope.  Physicians should always keep that diagnosis in the back of your mind when you have nothing on history or physical to guide them to an etiology.  Would I do a CT scan of the chest in everyone with syncope (especially knowing what we know about radiation exposure with CT scans?  Of course not. So why would we do an EEG, echo and carotid doppler on a patient who's subjective and objective data does not suggest they are necessary.

What does help in the evaluation of syncope?  Doing orthostatic blood pressures help.  I want to know what the patient's blood pressure and pulse are in the supine, sitting and standing position. A drop in systolic blood pressure of greater than 20 mmHg or a drop of diastolic blood pressure greater than 10 mmHg indicates the presence of orthostasis.   I don't know how nurses are trained to get orthostatic blood pressures, but I have to always remind them to get a pulse with the blood pressure.  A patient's pulse response to orthostasis is important for me to evaluate the drop.

Also don't forget about the carotid massage.  Can the physician induce a significant bradycardia by rubbing the carotid artery?  If so, they may have a sensitive carotid body and may need further cardiac workup.  Most of the time syncope is a benign situational vaso-vagal response to some emotional stimuli.  Usually it's an old guy with urinary retension or difficulty having a bowel movement.  Sometimes folks pass out in church.  We call that church syncope, or religious syncope.  It's a benign process.   Sometimes we prescribe beta-blockers and support hose and tell patients to avoid their syncope  triggers.  Vasovagal syncope won't kill you, unless you happen to be driving at 75 miles an hour at the time of your attack. 

Orthostasis and vaso vagal syncope are probably the two most common causes of syncope.  For orthostasis, a volume expansion will usually fix the problem.  Sometimes the patient may have adrenal insufficiency and the use of fludrocortisone or hydrocortisone may be indicated.  This is common in neurological conditions such as Parkinsons.  In addition, diabetic patients can often experience orthostatic hypotension, often caused by autonomic dysfunction.   

But this patient I got consulted on had something I'd never heard of.  They passed out when they swallowed liquids.  They had swallow syncope.  Every time they took a large gulp of soda,  they passed out.  They've done it in the past.  They did it in the hospital.  I saw the telemetry.  Impressive to say the least.  They had findings very similar to adenosine administration.  When your ventricles stop pumping blood to your brain, you will definitely  lose cerebral perfusion and pass out. 

Swallow syncope gives the patient a form of vagal mediated bradyarrhythmia or atrioventricular block.  According to one pub Med article, this can happen with cold carbonated beverages or with large boluses of food, termed the Vaso-Bagel Syndrome.  

The next time you have a patient with syncope, stop doing carotid dopplers, EEGs and echos.  Check their orthostatic blood pressures, rub their carotid and ask them about their relationship to food and drink.  And you might just diagnose them with swallow syncope or the Vaso-Bagel syncope.  How wild is that? 

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