Am Fam Physician. 2011 Apr 15;83(8):879-880.
to the editor: Drs. Post and Dickerson provide a useful review of the causes and treatments of dizziness and are appropriately conservative in their recommendations for diagnostic testing. However, in listing carotid artery stenosis as a cause of presyncopal dizziness, they perpetuate the belief that this entity is an important consideration in the evaluation of patients with presyncope (and by extension, syncope). This can lead to inappropriate diagnostic studies with consequential cost, anxiety, and false-positive and incidental findings.
The study cited by the authors in support of this statement does not mention carotid artery stenosis and instead uses the general term cerebrovascular disease, which includes conditions more likely to cause dizziness, such as stroke (nonspecific dizziness) and vertebrobasilar transient ischemic attack (vertigo).1 The study also lists transient ischemic attack as a “dangerous” cause of dizziness, but the likelihood of a transient ischemic attack presenting as isolated presyncopal dizziness is quite low.
Two reviews omit dizziness as a symptom of carotid artery disease and include vertigo as a symptom of vertebrobasilar disease only.2,3 Dizziness is specifically excluded as an acceptable symptom for evidence of a transient ischemic attack.3 Rarely, syncope may be a symptom of bilateral carotid artery stenosis4 or as a consequence of orthostasis and stenosis.5 The European Society of Cardiology states unambiguously that “no studies suggest that Doppler ultrasonography is valuable in patients with typical syncope.”6
Given the demographics of the population with presyncopal dizziness, many patients with dizziness have coexisting carotid artery disease. However, pursuing carotid artery stenosis as the cause of the dizziness will lead to delay, distraction, and increased cost before the true cause of the dizziness is determined.
1. Newman-Toker DE, Hsieh YH, Camargo CA Jr, Pelletier AJ, Butchy GT, Edlow JA. Spectrum of dizziness visits to US emergency departments: cross-sectional analysis from a nationally representative sample. Mayo Clin Proc. 2008;83(7):765–775.
2. Vanderhoff BT, Carroll W. Neurology. In: Rakel RE, ed. Textbook of Family Medicine. 7th ed. Philadelphia, Pa.: Saunders; 2007.
3. Biller J, Love BB, Schneck MJ. Vascular diseases of the nervous system: ischemic cerebrovascular disease. In: Bradley WG, Daroff RB Fenichel GM, Jankovic J, eds. Neurology in Clinical Practice. 5th ed. Philadelphia, Pa.: Butterworth-Heinemann; 2008.
4. Wilterdink JL, Furie KL, Kistler JP. Pathophysiology of symptoms from carotid atherosclerosis. http://www.uptodate.com/patients/content/topic (subscription required). Accessed September 1, 2010.
5. Mader SL. Orthostatic hypotension, dizziness, and syncope. In: Duthie EH Jr, Katz, PR, Malone ML, eds. Practice of Geriatrics. 4th ed. Philadelphia, Pa.: Saunders; 2007.
6. Moya A, Sutton R, Ammirati F, et al.; European Heart Rhythm Association. Heart Failure Association; Heart Rhythm Society; European Society of Emergency Medicine; European Federation of Internal Medicine; European Union Geriatric Medicine Society; American Geriatrics Society; European Neurological Society; European Federation of Autonomic Societies; American Autonomic Society. 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). Eur Heart J. 2009;30(21):2631–2671.
in reply: We appreciate Dr. Gillett's thoughtful comments and interest in our article. His points further emphasize that the practice of medicine requires making decisions based on the individual patient. His concerns about unnecessary testing are not unfounded, especially with the increasing costs of health care in the United States.
Dr. Gillett is concerned with our mentioning of carotid artery stenosis as a possible cause of dizziness. Although it is rare for carotid artery stenosis requiring intervention to cause presyncope or syncope,1 there have been some case reports of dizziness and/or syncope with various associated symptoms as a result of carotid artery occlusion.2–4 However, as we stated in our article, tests such as carotid Doppler should be performed only if an underlying cardiac cause is suspected based on other findings or known cardiac disease.
We agree that carotid Doppler testing should be reserved for patients in whom clinical suspicion is high, such as those with a history of smoking, peripheral vascular disease, or known carotid artery disease— all of which are shown to be associated with abnormal carotid ultrasound results.5 Using a high threshold for ordering these tests can minimize unnecessary testing that may lead to false positives and increased patient anxiety.
1. Grossman SA, Babineau M, Burke L, et al. Do outcomes of near syncope parallel syncope? [published ahead of print December 23, 2010]. Am J Emerg Med. http://www.ajemjournal.com/article/S0735-6757%2810%2900538-3/fulltext (subscription required). Accessed January 25, 2011.
2. Komiyama M, Yoshimura M, Honnda Y, Matsusaka Y, Yasui T. Percutaneous angioplasty of a chronic total occlusion of the intracranial internal carotid artery. Case report. Surg Neurol. 2006;66(5):513–518.
3. Lai SL, Chen YC, Weng HH, Chen ST, Hsu SP, Lee TH. Bilateral common carotid artery occlusion—a case report and literature review. J Neurol Sci. 2005;238(1–2):101–104.
4. Coutts SB, Hu W, Hill MD. Syncope and cerebral hypoperfusion. Neurology. 2003;60(12):2011.
5. Hill SL, Holtzman GL, Berry R, Arnold JF. The appropriate use of the duplex scan in carotid arterial disease. Am Surg. 1997;63(8):720–725.
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