Syncope
A common neurologic sign, syncope (or fainting) refers to transient loss of consciousness associated with impaired cerebral blood supply or cerebral hypoxia. It usually occurs abruptly and lasts for seconds to minutes. An episode of syncope usually starts as a feeling of light-headedness. A patient can usually prevent an episode of syncope by lying down or sitting with his head between his knees. Typically, the patient lies motionless with his skeletal muscles relaxed but sphincter muscles controlled. However, the depth of unconsciousness varies — some patients can hear voices or see blurred outlines; others are unaware of their surroundings.
In many ways, syncope simulates death: The patient is strikingly pale with a slow, weak pulse, hypotension, and almost imperceptible breathing. If severe hypotension lasts for 20 seconds or longer, the patient may also develop convulsive, tonic-clonic movements.
Syncope may result from cardiac and cerebrovascular disorders, hypoxemia, and postural changes in the presence of autonomic dysfunction. It may also follow vigorous coughing (tussive syncope) and emotional stress, injury, shock, or pain (vasovagal syncope, or common fainting). Hysterical syncope may also follow emotional stress, but isn’t accompanied by other vasodepressor effects.
Act Now: If you see a patient faint, ensure a patent airway, ensure his safety, and take his vital signs. Then place the patient in a supine position, elevate his legs, and loosen any tight clothing. Stay alert for tachycardia, bradycardia, or an irregular pulse. Meanwhile, place him on a cardiac monitor to detect arrhythmias. If an arrhythmia appears, give oxygen and insert an I.V. line for drugs or fluids. Be ready to begin cardiopulmonary resuscitation. Cardioversion, defibrillation, or insertion of a temporary pacemaker may be required.
Assessment
History
Ask the patient for information about the fainting episode. Did he feel weak, light-headed, nauseous, or sweaty just before he fainted? Did he stand quickly from a sitting or prone position? During the fainting episode, did he have muscle spasms or incontinence? How long was he unconscious? When he regained consciousness, was he alert or confused? Did he have a headache? Has he fainted before? If so, how often does it occur?
Physical examination
Perform a complete cardiac and neurologic examination. Provide continuous cardiac monitoring. Next, take the patient’s vital signs and examine him for injuries that may have occurred during his fall.
Pediatric pointers
Syncope is much less common in children than in adults. It may result from a cardiac or neurologic disorder, allergies, or emotional stress.
Medical causes
Aortic arch syndrome
With aortic arch syndrome, the patient experiences syncope and may exhibit weak or abruptly absent carotid pulses and unequal or absent radial pulses. Early signs and symptoms include night sweats, pallor, nausea, anorexia, weight loss, arthralgia, and Raynaud’s phenomenon. He may also develop hypotension in the arms, paresthesia, intermittent claudication, bruits, vision disturbances, dizziness, and neck, shoulder, and chest pain.
Aortic stenosis
A cardinal late sign, syncope is accompanied by exertional dyspnea and angina. Related findings include marked fatigue, orthopnea, paroxysmal nocturnal dyspnea, palpitations, and diminished carotid pulses. Typically, auscultation reveals atrial and ventricular gallops as well as a harsh, crescendo-decrescendo systolic ejection murmur that’s loudest at the right sternal border of the second intercostal space.
Cardiac arrhythmias
Any arrhythmia that decreases cardiac output and impairs cerebral circulation may cause syncope. Other effects — palpitations, pallor, confusion, diaphoresis, dyspnea, and hypotension — usually develop first. However, with Adams-Stokes syndrome, syncope may occur without warning. During syncope, the patient develops asystole, which may precipitate spasm and myoclonic jerks if prolonged. He also displays an ashen pallor that progresses to cyanosis, incontinence, bilateral Babinski’s reflex, and fixed pupils.
Carotid sinus hypersensitivity
Syncope is triggered by compression of the carotid sinus, which may be caused by turning the head to one side or by wearing a tight collar. The fainting episode is usually short.
Hypoxemia
Regardless of its cause, severe hypoxemia may produce syncope. Common related effects include confusion, tachycardia, restlessness, and incoordination.
Orthostatic hypotension
Syncope occurs when the patient rises quickly from a recumbent position. Look for a drop of 10 mm Hg or more in systolic or diastolic blood pressure as well as tachycardia, pallor, dizziness, blurred vision, nausea, and diaphoresis.
Transient ischemic attacks
Marked by transient neurologic deficits, these attacks may produce syncope and a decreased level of consciousness. Other findings vary with the affected artery, but may include vision loss, nystagmus, aphasia, dysarthria, unilateral numbness, hemiparesis or hemiplegia, tinnitus, facial weakness, dysphagia, and a staggering or an uncoordinated gait.
Vagal glossopharyngeal neuralgia
With this disorder, localized pressure may trigger pain in the base of the tongue, pharynx, larynx, tonsils, and ear, resulting in syncope that lasts for several minutes.
Other causes
Drugs
Quinidine may cause syncope — and possibly sudden death — associated with ventricular fibrillation. Prazosin may cause severe orthostatic hypotension and syncope, usually after the first dose. Occasionally, griseofulvin, levodopa, and indomethacin can produce syncope.
Nursing considerations
Continue to monitor the patient’s vital signs closely. Prepare the patient for an electrocardiogram, Holter monitoring, and carotid duplex, carotid Doppler, and electrophysiology studies.
Patient teaching
Advise the patient to pace his activities, to rise slowly from a recumbent position, to avoid standing still for a prolonged time, and to sit or lie down as soon as he feels faint.
Book Source Details
- Book Title: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series
- Author(s): Springhouse
- Year of Publication: 2007
- Copyright Details: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series, Copyright © 2007 Lippincott Williams & Wilkins.
Other Book Chapters Related to Dizziness
Read excerpts from these other book chapters related to Dizziness:
Copyright Details: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series, Copyright © 2008 Williams & Wilkins.
More About Causes of Dizziness
» Next page: Dizziness (Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series)
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