Operational Medicine 2001
Fainting

Introduction

Fainting episodes are common and are known in medical terms as syncope. Fainting is defined as a transient loss of consciousness accompanied by loss of postural tone with spontaneous recovery. 

Syncope is a symptom not a diagnosis. It has been reported that up to 48% of health individuals will have at least one fainting episode in their lifetime. Common causes of fainting include: 

• Vasovagal reaction
• Orthostatic hypotension
• Situational syncope

Less common are cardiac and neurologic causes. 

The etiology of most cases of fainting can easily be found with a good history and physical. Expensive test and labs are not frequently needed for the work up of fainting. A definitive cause may not be found in 40% of the cases, despite a careful evaluation.

History

History plays the largest part in finding the underlying cause of fainting. History should focus on separating cardiac from noncardiac causes of fainting. Cardiac causes are more serious with a high mortality associated with them.  Often, patients are not able to give a thorough history secondary to the fainting episode, but a witness of the episode may prove helpful. The onset and recovery surrounding the event provides clues to the diagnosis:

• Postural changes- going from a supine or sitting position to standing suggests orthostatic hypotension.
• Numbness of the hands and perioral area- often seen in patients with hyperventilation syndromes.
• Exertional fainting- can be seen with cardiac causes.  In the young patient complaining of sudden fainting with exercise hypertrophic cardiomyopathy should be entertained.  In older to elderly patients aortic stenosis can cause fainting.  The harsh systolic murmur of aortic stenosis must be present in order for this to be the cause.
• Laughter, meals, urination, and defecation- these activities can produce vasovagal fainting associated with valsalva.
• Palpitations- complaint of irregular heart beating prior to the fainting can be seen with arrhythmias.
• Chest pain- can denote the onset of myocardial infarction, but this rarely causes fainting.
• Shaving or tight fitting collars- carotid pressure has been reported to cause fainting.
• Neurologic symptoms- witnesses often testify to tonic-clonic activity, post-ictal confusion and even loss of bowel or bladder control, all of which are present with seizures.
• No warning signs- arrhythmias can present acutely.

Physical Exam

The history should help tailor the physical exam.  Obtain vital signs while standing, sitting, and reclining. Carotid message and valsalva maneuvers can be performed if warranted. Listen to the heart and perform a neurologic exam

Labs

The only lab or test that should be obtained, if available, is a 12 lead EKG.  It has a low yield, however, with only 5% of cases are diagnosed by the EKG findings.  No other lab or test has as high a yield as an EKG and hence are not recommended.

Plan

If the cause of fainting is non-cardiac, reassurance and education become the foundation of treatment.  Most causes of fainting, especially in the young, are non-cardiac.  In cases of true cardiac causes or onset of seizures appropriate referrals and transfers is warranted.      

This section provided by LT Ronnie L. Garcia, MC, USNR, Naval Medical Center Portsmouth

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Operational Medicine 2001
Health Care in Military Settings

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