Diagnostic Considerations

There are well-publicized implications of patients with syncope returning to activities such as sports, driving, and operating machinery. Consultation with a subspecialist and/or a hospital attorney may be prudent prior to making definitive recommendations.

Elderly patients with dementia and episodes of suspected sycope may have an atypical clinical presentation and render it difficult to use a standard diagnostic protocol for syncope.^[6]These patients also suffer frequent unexplained falls.

Note the following:

Consider and diagnose life-threatening etiologies of syncope
Scrutinize the initial electrocardiogram (ECG) and seek comparison to a prior ECG
Provide adequate subspecialty and/or primary care follow-up
Educate patients adequately about the etiology of the syncope and preventive measures to avoid recurrence
Adequately address short-term recurrence probability and ensure low risk of subsequent morbidity
Consider and diagnose life-threatening conditions that occur as a result of the syncopal episode

Vasomotor/vascular conditions to consider in patients with suspected syncope include the following:

Dehydration
Diabetic neuropathy
Diuresis
Drug-induced orthostasis
Dysautonomia
Ectopic pregnancy
Hemorrhage
Hypotension
Hypovolemia
Multisystem atrophy
Peripheral polyneuropathy
Postural hypotension
Subclavian steal
Vasodepressor/vasovagal response
Vasomotor insufficiency

Cardiac conditions to consider in patients with suspected syncope include the following:

Bradydysrhythmias
Cardiac myxoma
Cardiac outflow obstruction
Dysrhythmias
Hypertrophic subaortic stenosis
Paroxysmal supraventricular tachycardia
Paroxysmal ventricular tachycardia
Primary pulmonary hypertension
Prolonged QT syndrome
Sick sinus syndrome
Sinoatrial block
Sinus pause (>3 s)
Tachydysrhythmias
Tricuspid stenosis

Situational conditions to consider in patients with suspected syncope include the following:

Carotid sinus syncope
Cough (posttussive) syncope
Defecation syncope
Micturition syncope
Postprandial syncope
Swallow syncope

Metabolic/endocrine conditions to consider in patients with suspected syncope include the following:

Hypothyroidism
Hypoxemia
Pheochromocytoma

Central nervous system conditions to consider in patients with suspected syncope include the following:

Hyperventilation syndrome
Hydrocephalus
Migraine headache
Narcolepsy
Panic attacks
Seizure disorder

Differential Diagnoses

Workup

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Author

Rumm Morag, MD, FACEP Member of Salem Emergency Physician Services, PC (SEPS), Salem Hospital

Rumm Morag, MD, FACEP is a member of the following medical societies: American College of Emergency Physicians, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Coauthor(s)

Barry E Brenner, MD, PhD, FACEP Program Director, Emergency Medicine, Einstein Medical Center Montgomery

Barry E Brenner, MD, PhD, FACEP is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Chest Physicians, American College of Emergency Physicians, American College of Physicians, American Heart Association, American Thoracic Society, New York Academy of Medicine, New York Academy of Sciences, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Eddy S Lang, MDCM, CCFP(EM), CSPQ Associate Professor, Senior Researcher, Division of Emergency Medicine, Department of Family Medicine, University of Calgary Faculty of Medicine; Assistant Professor, Department of Family Medicine, McGill University Faculty of Medicine, Canada

Eddy S Lang, MDCM, CCFP(EM), CSPQ is a member of the following medical societies: American College of Emergency Physicians, Society for Academic Emergency Medicine, Canadian Association of Emergency Physicians

Disclosure: Nothing to disclose.

Chief Editor

Erik D Schraga, MD Staff Physician, Department of Emergency Medicine, Mills-Peninsula Emergency Medical Associates

Disclosure: Nothing to disclose.

Additional Contributors

David A Peak, MD Associate Residency Director of Harvard Affiliated Emergency Medicine Residency; Attending Physician, Massachusetts General Hospital; Assistant Professor, Harvard Medical School

David A Peak, MD is a member of the following medical societies: American College of Emergency Physicians, Society for Academic Emergency Medicine, Undersea and Hyperbaric Medical Society, American Medical Association

Disclosure: Partner received salary from Pfizer for employment.

Syncope Differential Diagnoses

Diagnostic Considerations

Differential Diagnoses

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