Case

Hi, we have a 13-year old girl who was brought in by ambulance after she passed out today at school. She was standing in line at the cafeteria during lunchtime. The teacher reports that she fell to the ground while in line and woke up almost immediately. The teacher stated that she looked pale. She looks well now and the vitals are all stable. Should we be concerned? Should we do any testing?

What am I thinking?

This is a classic story for vasovagal syncope (VVS). However, I would want to make sure they are not missing something more dangerous. Vasovagal syncope (sometimes called by various other names like “simple” fainting, or the more scientific, “neurocardiogenic syncope”) implies that the faint was due to loss of blood pressure maintaining reflexes with hypotension and fainting. It is extremely common and teenagers seem to be particularly more prone to such faints. There are typical scenarios where such fainting happens such as lined up in a crowded cafeteria and hungry (hypoglycemia as a factor). Studies have shown that 99% of faints in teenagers are due to VVS and only 1% have something concerning going on.

History and physical

The most important aspect in evaluating someone who has fainted is the history. Attention should be paid to the detailed history of the event. Here, we have the history that the teenager was standing in the lunch line. VVS almost always happens while the person is either sitting or standing and almost never happens while the person is lying down. Another aspect to inquire is about dehydration and hunger. Was the patient ill in some way with diarrhea or vomiting? Has he or she not been drinking adequate liquids? Have they been not eating properly? A child who is late to school and runs out of the house not having had breakfast is much more likely to faint while standing in a cafeteria lunch line.

Other scenarios where fainting often occurs due to loss of blood pressure are while prolonged standing (parade ground, marching band, church), sudden standing, hypoglycemia, dehydration, during micturition in boys, during hairstyling or combing while standing in girls, after a sudden painful event (such as having blood drawn or an injection), or after seeing something scary or revolting (the sight of blood for example). Fainting is more common in hot weather or environments.

VVS is often, though not always, accompanied by a typical prodrome that consists of descriptions like tunnel vision, a headache or a heavy-headed feeling, nausea, feeling hot all over, feeling cold all over, and/or a numbness or tingling sensation in various parts of the body. Witnesses may describe the patient as pale or diaphoretic before the faint. Fainting during the act of physical exercise should be assumed to be a dangerous faint unless proven otherwise. Fainting minutes after completion of a physically challenging event is often VVS (see Chapter 17 ), but it is better to exercise caution and be more thorough in all exercise-related faints.

The loss of consciousness during VVS is typically brief. There may be stiffening of the body or, rarely, a shivering type movement. Eye rolling can happen. Rhythmic jerky movements are rare and should suggest a seizure as the cause. Incontinence of bowel or bladder is almost never present in VVS. Physical recovery after VVS is typically rapid and complete although some fatigue may persist for the remainder of the day.

An important question to ask in the history is to see if there has been any family member who has died in a sudden or unexplained manner. This may include specifically asking if anyone went to sleep and never woke up, if someone who knew swimming was found drowned, unusual and hard to explain car accidents (where the person may have passed out before the accident). The presence of such a history increases the likelihood that there may be an underlying hereditary condition (like hypertrophic cardiomyopathy or long QT syndrome) that is associated with sudden death. Long QT syndrome has a specific and peculiar association with death during swimming and also with passing out after a sudden, alarming noise.

Physical examination is normal in patients with VVS. Examination should focus on ruling out concerning findings for cardiac disease such as rhythm abnormalities or additional cardiac sounds such as murmurs, rubs, or gallops. Assessment of hydrational status may also be useful for further management.

Diagnostic testing

In most patients where the history is highly suggestive of VVS, the only test that helps is a standard ECG. The ECG can help identify cardiomyopathy, long QT, and Wolff Parkinson White (rare cause of sudden death). If the history is clear, physical exam unremarkable, and ECG is normal, a diagnosis of VVS can be made with confidence. It is particularly important to avoid wasteful tests like CT scan of the brain, EEG, and echocardiograms, as their yield is usually extremely low in the patient with classic presentation of VVS.

Patients with exercise-associated syncope should get an echocardiogram, mainly to look for cardiomyopathy (hypertrophic cardiomyopathy being the most common offender) and to look specifically at the origins and initial course of the coronary arteries. An anomalous left coronary artery coming off the right-facing sinus and winding its way with an intramural (inside the vessel wall) course is the most common congenital coronary anomaly associated with exercise-induced ventricular fibrillation and sudden death. Less frequently, one may detect an anomalous right coronary artery arising from the right sinus and then going to the left. While reduced cardiac function is easy to detect, identifying the coronary arteries reliably by echocardiogram needs experience and skill, which is not something that can be done by a quick point of care echocardiogram. If the echocardiogram is normal and there is still concern about the syncope, other tests to consider would be an exercise test (if the syncope was associated with exercise), or a Holter or longer ECG monitor to try and catch the ECG during an episode.

Action plan

Management of VVS basically consists of reassurance that it will improve as the child gets older and encouraging a diet higher in salt and increased water intake. Patients should be encouraged to drink at least 64 oz of noncaffeinated beverages per day and add a daily salty snack to their diet. Patients are advised that when their prodrome occurs and they feel “faint,” they should immediately lay down with their legs up to help prevent injury and improve symptoms. In fact, one may say that VVS is nature’s way of telling someone to lie down.

Most patients respond well to these simple measures. Those who fail this will usually need a specialist referral. Anxiety and emotional stress are commonly associated with fainting. Patients with an anxiety disorder can be complex to manage and would not be amenable to standard VVS treatment. Specialist psychology or psychiatry referral should be strongly considered.

The 1% of patients who have something else more malignant are either those with a seizure disorder mistakenly diagnosed as a faint, or else cardiac conditions that put them at risk for cardiac arrest and sudden death. Such cardiac conditions include cardiomyopathies, channelopathies like long QT syndrome, or else abnormal coronary arteries (see Chapter 18 ). The common factor in all is the etiology of lethal ventricular arrhythmias. Therefore, the “faint” may be a warning that something more serious could happen.