#32 Syncope Deconstructed

March 27, 2017 | By Matthew Watto, MD

Dominate syncope with tools, tips, and tricks from The Curbsiders. No guest on this episode, just doctors Watto, Brigham, and Williams deconstructing the frustrating topic of syncope to provide listeners with some shiny clinical pearls and practice changing knowledge.

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Clinical Pearls:

1. Syncope: transient loss of consciousness (LOC) with rapid onset, short duration, spontaneous recovery, loss of postural tone and with global cerebral hypoperfusion
2. Pathophysiology: vasodepressor (drop in peripheral resistance and BP), cardioinhibitory (decrease cardiac output), or combination of both
3. Reflex syncope: vasovagal (emotion, or orthostatic stress), situational (e.g. cough, micturition, defecation, etc.), carotid sinus hypersensitivity
4. Cardiac syncope: structural (CHF, valvular, thrombosis, tumor, tamponade), arrhythmia, cardiopulmonary (pulmonary embolism, pulmonary HTN)
5. Orthostatic hypotension (OH): primary autonomic failure (ANF) e.g. parkinson’s; secondary ANF e.g. diabetes, amyloidosis; drug induced; volume depletion; venous pooling
6. Orthostatic blood pressure: check after supine 5 min, then immediately upon standing, then again after >3 min standing (Curbsiders’ recommendation). Positive if drop in SBP >20mmHg, or DBP >10mmHg.
7. Carotid sinus massage: sequential massage of right and left carotid artery at bifurcation for 5 seconds. Positive if syncope, >50mmHg drop in BP, or >3 seconds of asystole. Perform while on EKG monitor, and check BP frequently.
8. Pulmonary embolism: Cause in ~1 of 6 hospitalized w/1st episode syncope, BUT ~1 of 4 hospitalized with uncertain cause of syncope (see PESIT study below)
9. Epilepsy: tongue biting on sides (versus tip in syncope), >1 minute synchronous movements that begin before falling, postictal state (confusion). Urinary incontinence can occur in syncope or seizure.
10. Echocardiogram: needed if EKG abnormal or cardiac cause suspected. NOT for all comers.
11. Cardiac monitoring: Yield is 18% during 3-5 days in hospital.
12. CNS imaging: Unnecessary unless head trauma, or new focal neurodeficit.
13. Carotid ultrasound: Unnecessary. Carotid CVA/TIA almost never causes LOC.
14. Vertebrobasilar TIA: Limb weakness, ataxia, oculomotor palsy, oropharyngeal dysfunction. LOC not always present (versus syncope where LOC is a given)
15. EEG: only needed if history suggests seizures
16. Physical counterpressure maneuvers: tensing of muscles in hands, arms, crossing of legs, or squatting to boost BP
17. Compression stockings: must be at least thigh high
18. Acute water ingestion: 240 to 480ml of cold water causes an acute increase in SBP
19. Midodrine may be considered if nonpharmacologic therapy ineffective

Goal: Listeners will employ a systematic and practical approach to the diagnosis and management of syncope.

Learning objectives:
By the end of this podcast listeners will:

1. Define syncope
2. Classify syncope into the 3 main categories
3. Recall how to measure and interpret orthostatic blood pressure readings
4. Utilize carotid sinus massage to diagnose carotid hypersensitivity
5. Identify pulmonary embolism as potential cause for unexplained syncope
6. Employ nonpharmacologic therapies for vasovagal and orthostatic hypotension
7. Avoid unnecessary testing in the workup of syncope

Disclosures:
The Curbsiders reports no relevant financial disclosures, but hope to have several to report in the near future.

Time Stamps
00:00:00 Intro
00:01:33 Picks of the week
00:07:47 Hops, beer and PCSK9 inhibitors
00:10:50 A case of syncope
00:13:45 Syncope defined, classified
00:17:50 Orthostatic vital signs and delayed OH
00:24:30 High risk features
00:27:00 Avoid the shotgun workup for syncope
00:31:06 Differentiate epilepsy from syncope
00:34:09 Brief review of cardiac monitoring
00:36:27 Nonpharmacologic treatment of syncope
00:43:38 Medications for syncope
00:45:48 Recap of diagnosis and management
00:47:56 Carotid sinus massage
00:52:25 Tilt table testing
00:53:51 Syncope and pulmonary embolism
00:58:34 Back tot the case
01:01:32 Outro

Links from the show:

1. Prisoners (film) by Denis Villeneuve 2013
2. Get Out (film) by Jordan Peele 2017
3. Against Medical Advice by Z Dogg MD
4. Switch: How to change things when change is hard (book) by Chip and Dan Heath
5. Jon Whitney’s podcast is Brainwashed Radio on iTunes
6. Courtney Cook’s nonprofit makes AirRx app available on iTunes
7. Article on Xanthohumol, hops, beer, and PCSK9 from Archives of BioChem and BioPhysics 2016
8. 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines, and the Heart Rhythm Society. J Am Coll Cardiol 2017;Mar 9:[Epub ahead of print].
9. Prandoni, P et al (The PESIT Investigators). Prevalence of Pulmonary Embolism among Patients Hospitalized for Syncope. N Engl J Med 2016; 375:1524-1531October 20, 2016DOI: 10.1056/NEJMoa1602172
10. Moya, A et al. Guidelines for the diagnosis and management of syncope (version 2009) The Task Force for the Diagnosis and Management of Syncope of the European Society of Cardiology (ESC). European Heart Journal (2009) 30, 2631–2671 doi:10.1093/eurheartj/ehp298
11. Syncope risk score from Canada (Prospective Study) NEJM Journal Watch
12. Am J Med. 2002 Apr 1;112(5):355-60. Water drinking as a treatment for orthostatic syndromes.  Shannon JR et al.