Syncope overview: Difference between revisions
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Revision as of 18:22, 22 April 2020
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Syncope Microchapters |
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Diagnosis |
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Treatment |
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Syncope overview On the Web |
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American Roentgen Ray Society Images of Syncope overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Syncope (IPA: Template:IPA and Template:IPA), is a sudden, and generally momentary, loss of consciousness, or blacking out caused by the Central Ischaemic Response, because of a lack of sufficient blood and oxygen in the brain. The first symptoms a person feels before fainting are dizziness; a dimming of vision, or brownout; tinnitus; and feeling hot. Moments later, the person's vision turns black, and he or she drops to the floor (or slumps if seated in a chair). If the person is unable to slump from the position to a near horizontal position, he or she risks dying of the Suspension trauma effect. More serious causes of fainting include cardiac (heart-related) causes such as an abnormal heart rhythm (an arrhythmia), where the heart beats too slowly, too rapidly or too irregularly to pump enough blood to the brain. Some arrhythmias can be life-threatening. Other important cardio-vascular conditions that can be manifested by syncope include subclavian steal syndrome and aortic stenosis.
Historical Perspective
Classification
Vasovagal (situational) syncope, one of the most common types, may occur in scary or embarrassing situations or during blood drawing, coughing, or urinating. Other types include postural syncope (caused by a changing in body posture), cardiac syncope (due to heart-related conditions), and neurological syncope (due to neurological conditions). There are many other causes of syncope including low blood sugar levels and lung disease such as emphysema and a pulmonary embolus. The cause of the fainting can be determined by a doctor using a complete history, physical, and various diagnostic tests.
Pathophysiology
Causes
Differentiating Syncope from other Diseases
Screening
Epidemiology and Demographics
Risk Factors
Natural History, Complications, and Prognosis
Diagnosis
History and Symptoms
Physical Examination
Laboratory Findings
Electrocardiogram
Electrocardiogram and Holter monitoring can help to analyze the electrical activities of the heart. They can supply information about the heart rhythm and indirectly, the heart size. It may help a doctor determine the relationship between syncope and any possible arrhythmias. Compared to a Holter monitor, electrophysiologic studies have a higher diagnostic yield, and it should be ordered for any patient with a suspected arrhythmia.
X-ray
There are no x-ray findings associated with syncope.
CT
Head images such as CT and MRI, may be useful to check for brain diseases that can cause syncope. A CT scan can show brain structure and locate lesions and its surrounding tissues. An MRI uses magnetic fields to produce detailed images of the body, but it is a different type of image than what is produced by computed tomography (CT).
MRI
Echocardiography
In patients with known heart disease, echocardiography is needed to check the heart structure and assess left ventricular function. It uses sound waves to produce an image of the valves, ventricles and atrium. The image shows the structure of the mitral valve and its movement during the beating of the heart.
Other Diagnostic Studies
A tilt table test can help to reveal abnormal cardiovascular reflexes that produce syncope. During the test, you stand and your initial blood pressure and heart rate are recorded as the baseline. Then the table is tilted at 70 degrees for 45 minutes. Your blood pressure and heart rate are recorded again. At the same time, the nurse observes whether symptoms such as nausea or vomiting appear. A positive result suggests the possibility of vasovagal syncope.
Other Diagnostic Studies
Treatment
Medical Therapy
Surgery
Primary Prevention
There are no established measures for the primary prevention of syncope.
Secondary Prevention
There are no established measures for the secondary prevention of syncope.