How Common is Syncope?

Patient Presentation
A 10-year-old female was referred to cardiology clinic after an episode of syncope 1 week previously. After she had been running sprints at the end of a sports practice, she went to the bathroom. After voiding, she stood up, felt lightheaded, warm, shaky, her heart was beating faster than it had been, she had blackness in her vision and then collapsed.
She had no bladder or bowel incontinence. She does not know how long she was unconscious for, but a friend helped her get up.
She reports dizziness at other times when she gets up quickly. One episode occurred about a month ago. She did not lose consciousness and says she continued her activities.
She says she does drink water and sports drinks, and only urinates one time during the school day. She reports no caffeine or additional salt intake in her diet.
She says she has no chest pain, palpitations, exercise intolerance or shortness of breath.
The past medical history and review of systems are otherwise negative.
The family history is negative for syncope, heart abnormalities, seizures and sudden death.
The pertinent physical exam shows a healthy appearing school age female. Pulse is 72, respirations are 20, and blood pressure in the right arm is 102/61 with no significant differences in other extremities.
Height and weight are in the 50-75% for age. Neck had no lymphadenopathy or thyromegaly. Lungs were clear. Heart showed a regular rate and rhythm without murmurs. Normal S1 without murmurs and normal splitting of S2.
Pulses were equal in upper and lower extremities. Neurological examination was also normal.
The work-up included an electrocardiogram which showed mild sinus bradycardia with a heart rate of 55 but was otherwise normal including a correct QT interval with no pre-excitation.
The diagnosis of reflex syncope was made. She was advised to increase her fluid intake, add a moderate amount of salt to her food and to limit caffeine intake. If the symptoms return she will then call for followup.

Transient loss of consciousness (TLOC) is a common presenting problem in children. Physical collapse may or may not be associated with TLOC as a presenting problem.
The differential diagnosis of TLOC and collapse is often compounded by imprecise terminology use.

The following algorithm can be considered when trying to differentiate between the multiple causes of collapse and TLOC.

1. Did the patient collapse? (defined as abrupt loss of postural tone with or without TLOC)

  • No – consider other causes
  • Yes – ask question 2 below

2. Did the patient have a spontaneous TLOC?

  • No – consider the causes below:
    • Falls
    • Hypoglycemia or other metabolic abnormalities
    • Medication side effects or drug abuse
    • Transient ischemic attack or cerebrovascular accident
  • Yes – consider the causes below:
    • Syncope (defined as TLOC caused by global impairment of cerebral perfusion which then causes the collapse. Onset is relatively rapid, recover is spontaneous, complete and usually prompt. )
    • Epilepsy (defined as spontaneous inappropriate discharge of cortical neurons leading to a clinical event)
    • Psychogenic seizure (defined as a transient neurological disturbance without organic cause)

Epilepsy is also a common of TLOC. Unfortunately, there is a high rate of misdiagnosing epilepsy as the cause when other causes are the real culprits. In children, the misdiagnosis rate is as high as 40%.
Epilepsy is a clinical diagnosis, but neurological consultation is necessary to confirm the diagnosis. Electroencephalogram also may be helpful in confirming the diagnosis.

Psychogenic seizures are often seen in children and adults under age 50. The episodes are frequent, often occurring many times per day, but testing shows that the TLOC occurs without any change to blood pressure, heart rhythm or electroencephalic tracings.
Tilt table testing may be help to make these determinations and reassuring the patient and family that there is no underlying cardiac or neurological events. Tilt table testing is being used less frequently though because of lack of sensitivity and specificity. Treatment with psychiatric help can then be offered.

Learning Point

Syncope is common with ~15% of children under the age of 18 having the problem. More females than males have syncope.

Reflex syncope, also known by many other names including vasovagal syncope, neurocardiogenic syncope, pallid breath holding spells and others, is probably the most common cause of syncope.
The initial event causing the reflex syncope is not known but higher cerebral centers appear to be involved. Some speculate that reflex syncope may be an evolutionary adaption, whereby in response to a predator, a person will abruptly collapse and become pallid. The person would appear to be dead to the predator and thereby escape being prey.
Reflex syncope usually has a history of associated symptoms such as nausea, vomiting, feeling hot, sweating, lightheadedness, “closing in of vision” and palpitations. The patient also turns pale and consciousness quickly returns. There is often a precipitating event such as standing for a long period of time in a hot environment, a frightening episode such as the sight of blood, or intense pain or trauma.
Recommended treatments include avoid caffeine (to avoid its diuretic effects), increasing fluid intake, and adding some salt (to increase fluid retention). Some cardiologists recommend sports drinks if patients are very active.
Also having the patient be aware of common precipitating events so they can be avoided or modified, e.g. arising slowly after sitting for a long time. Patients often have resolution of the episodes within 6-9 months.

Syncope after exercise is often caused by reflex syncope.
Syncope during exercise may be caused by an underlying cardiomyopathy or arrhythmia and should be investigated. Any family history of underlying cardiac disease should also prompt investigation. Other indications for referral to a cardiologist include episodes that includes chest pain, palpitations, an abnormal electrocardiogram, syncope that causes injury or recurrent syncope.
Some physicians recommend that any patient who has a syncopal episode have an electrocardiogram at least once. A search of clinical practice guidelines of the American Academy of Pediatrics, American Academy of Neurology and the American Heart Association did not find any specific recommendations for syncope and its evaluation.

Questions for Further Discussion
1. What are indications for an electroencephalogram?
2. What are the indications for Holter monitoring?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Information prescriptions for patients can be found at MedlinePlus for these topics: Fainting, Arrhythmia and Epilepsy
and at Pediatric Common Questions, Quick Answers for this topic: Fainting and Epileptic Seizures.

To view current news articles on this topic check Google News.

Fitzpatrick AP, Cooper P. Diagnosis and management of patients with blackouts.
Heart. 2006 Apr;92(4):559-6.

Rudolph CD, Rudolph’s Pediatrics. 21st edit. McGraw-Hill, New York, NY. 2003:1892-1894.

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    5. Patients and their families are counseled and educated.

    7. All medical and invasive procedures considered essential for the area of practice are competency performed.
    8. Health care services aimed at preventing health problems or maintaining health are provided.
    9. Patient-focused care is provided by working with health care professionals, including those from other disciplines.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Practice Based Learning and Improvement
    12. Evidence from scientific studies related to the patients’ health problems is located, appraised and assimilated.
    13. Information about other populations of patients, especially the larger population from which this patient is drawn, is obtained and used.

  • Systems Based Practice
    24. Cost-effective health care and resource allocation that does not compromise quality of care is practiced.
    25. Quality patient care and assisting patients in dealing with system complexities is advocated.
    26. Partnering with health care managers and health care providers to assess, coordinate, and improve health care and how these activities can affect system performance are known.

    Donna M. D’Alessandro, MD
    Associate Professor of Pediatrics, Children’s Hospital of Iowa

    Nicholas Von Bergan, M.D.
    Pediatric Cardiology Fellow, Children’s Hospital of Iowa

    March 5, 2007