Transient loss of consciousness and syncope
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Published on: March 21, 2013
1Department of Neurology, University Hospital of Bern (Inselspital), Bern, Switzerland.
Insights
Syncope, a transient loss of consciousness (TLOC), results from reduced blood flow to the brain. Diagnosis involves history, physical exam, and ECG, with further tests guided by clinical context.
Area of Science:
- Neurology
- Cardiology
- Internal Medicine
Background:
- Syncope is a sudden, brief loss of consciousness with postural failure due to global cerebral hypoperfusion.
- Transient loss of consciousness (TLOC) encompasses both syncopal and nonsyncopal causes.
- Common syncopal causes include cardiogenic, orthostatic hypotension, and neurally mediated syncope.
Purpose of the Study:
- To outline the causes and diagnostic approaches for syncope and TLOC.
- To differentiate syncopal from nonsyncopal TLOC.
- To provide an overview of diagnostic workup and management strategies.
Main Methods:
- Review of common and rare causes of syncope and nonsyncopal TLOC.
- Description of diagnostic workup, including history, physical examination, and ECG.
- Mention of specific diagnostic tests like EEG, MRI, echocardiography, and tilt testing when indicated.
Main Results:
- Syncope is primarily caused by cardiac, orthostatic, or neural factors.
- Nonsyncopal TLOC can stem from neurological, medical, psychiatric, or post-traumatic conditions.
- Diagnostic workup is stratified, starting with basic assessments and progressing to specialized tests as needed.
Conclusions:
- Effective management of syncope and TLOC requires accurate diagnosis based on clinical presentation.
- Diagnostic strategies should be tailored to the individual patient's suspected cause.
- Treatment options range from lifestyle modifications and medications to cardiac pacing.
Abstract:
Syncope describes a sudden and brief transient loss of consciousness (TLOC) with postural failure due to cerebral global hypoperfusion. The term TLOC is used when the cause is either unrelated to cerebral hypoperfusion or is unknown. The most common causes of syncopal TLOC include: (1) cardiogenic syncope (cardiac arrhythmias, structural cardiac diseases, others); (2) orthostatic hypotension (due to drugs, hypovolemia, primary or secondary autonomic failure, others); (3) neurally mediated syncope (cardioinhibitory, vasodepressor, and mixed forms). Rarely neurologic disorders (such as epilepsy, transient ischemic attacks, and the subclavian steal syndrome) can lead to cerebal hypoperfusion and syncope. Nonsyncopal TLOC may be due to neurologic (epilepsy, sleep attacks, and other states with fluctuating vigilance), medical (hypoglycemia, drugs), psychiatric, or post-traumatic disorders. Basic diagnostic workup of TLOC includes a thorough history and physical examination, and a 12-lead electrocardiogram (ECG). Blood testing, electroencephalogram (EEG), magnetic resonance imaging (MRI) of the brain, echocardiography, head-up tilt test, carotid sinus massage, Holter monitoring, and loop recorders should be obtained only in specific contexts. Management strategies involve pharmacologic and nonpharmacologic interventions, and cardiac pacing.
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