Journal of Cardiovascular Disease Research |Year 2017 | Volume 8 | Issue 3 |Page 66-71
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Sylvia Biso, Supakanya Wongrakpanich, Akanksha Agrawal, Sujani Yadlapati, Marina Kishlyansky Do, Mary Rodriguez Ziccardi, Toni Anne De Venecia
Department of Medicine, Einstein Medical Center, 5401 Old York Road, Suite 363, Philadelphia, USA.
CorrespondenceSylvia Biso, MDDepartment of Medicine, Einstein Medical Center, 5401 Old York Road, Suite 363, Philadelphia, USA.Ph.no: 7329251547Fax: 215-455-1933E-mail address: BisoSylv@einstein.edu
Submission Date: 18-02-2016;
Revision Date: 19-05-2016;
Accepted Date: 11-06-2016.
DOI : 10.5530/jcdr.2017.3.17ABSTRACT
Syncope is a common and pervasive medical problem. The etiology of 30-40% of syncope remains unknown. Laughter-induced syncope is a rare subtype of vasovagal syncope that is not well understood. With this literature review we hope to elucidate the epidemiology, symptomatology, pathophysiology, diagnosis and therapeutic options of laughter-induced syncope. Greater awareness of laughter-induced syncope may better direct clinical investigations and improve patient care.
Keywords: Laughter-induced syncope, Situational syncope, Gelastic syncope, Sitcom syncope, Syncope.INTRODUCTION
Syncope is defined as an acute loss of consciousness secondary to brief global cerebral hypoperfusion associated with a lack of ability to maintain postural control. Episodes of syncope are sudden in onset, transient, and occur with full spontaneous recovery.1 The prevalence is similar between genders (30–50%), increasing proportionally with age and accompanied by a sharp rise in prevalence after the age of 70.2,3 Syncope represents 3–5% of emergency department visits.3 Of those people presenting to the emergency department for syncope, 40% of patients are subsequently admitted.4
Causes of syncope can be categorized into vasovagal (21.2%), stroke (4.1%), seizure (4.9%), orthostatic (9.4%), cardiac (9.5%), medication (6.8%), unknown (36.6%) and situational syncopes (7.5%).2 When reflex-mediated syncope occurs in conditions that precipitate the Valsalva maneuver, such as laughing, carrying weight, defecation, or coughing, it is called situational syncope. Only around 8% of all syncope is situational. Laughter-induced syncope is a rare subtype of situational syncope and there have been only a few cases described in literature.
Laughter-induced syncope is also called gelastic syncope, from the Greek word “gelastikos” or “able to laugh”. The first published case report of laughter-induced syncope was by Cox et al. in 1997.5 The patient had a brachiocephalic stenosis and lost consciousness while watching Seinfeld. From then on, laughter syncope was also known as “Seinfeld syncope” or “Sitcom syncope”. To the best of our knowledge, there are about 19 cases of laughter-induced syncope published in literature. Case reports on laughter-induced syncope are summarized on Table 1.
Some of the patients, similar to the case by Cox and colleagues, have underlying medical conditions that contributed to the syncope, such as ependymoma or Takayasu’s arteritis.5 Most cases are reported to occur in the elderly or in those with co-morbidities such as diabetes mellitus and coronary artery disease. In only in a few instances has laughter-induced syncope involved young and healthy individuals. History taking is the basis of diagnosing patients who present with syncope. This is especially true in patients with situational syncope. Although there is currently no diagnostic gold standard, history, physical exam and electrocardiography have a combined diagnostic yield of 50% in determining the etiology of syncope.6 A strong temporal relationship between the triggering events and the syncopal episodes supports a diagnosis of situational syncope. For laughter-induced syncope, history will reveal vigorous laughter immediately prior to the syncope. It always involves a brief loss of consciousness with quick resolution of symptoms.
Previous case reports showed that laughter-induced syncope happens infrequently (Table 1). Although two of the patients have episodes of more than five times, patients usually only have 3-5 prior episodes of syncope before being diagnosed. Many only have one reported episode. Lightheadedness, dizziness, visual blurring or darkening of visual field may sometimes accompany these laughter-induced syncopes. Two patients with an underlying carotid artery and brachiocephalic stenoses described an associated amarausis fugax. These symptoms are non-specific, but when such prodromal symptoms are present, patients can try to avoid the ensuing syncope by curtailing their laughter. In our patient, his prior episodes were only pre-syncopal. There is some lightheadedness, but he is otherwise asymptomatic.
Diagnostic tests do not play a major role in diagnosing situational syncopes. They are usually used to rule-out underlying cardiac or neurologic causes of syncope. They are also done to determine if there are other underlying etiologies or reversible causes. For laughter-induced syncope, diagnostic tests are commonly negative. In the literature, the ECGs of the reported cases were mostly normal. There are no predominant bradyarrhythmias or tachyarrhythmias. Holter monitoring was done in eight of them to detect underlying arrhythmias and the results were negative. Echocardiograms would predominantly be normal. The results of cardiac stress tests in the literature have been negative for ischemia except for one patient.
Tilt testing is a diagnostic adjunct that is commonly employed in vasovagal syncope and its subtypes. For laughter syncope patients who underwent tilt table testing, results have been positive. Loss of consciousness, a drop in blood pressure or a change in heart rate has been elicited during tilt table testing in some of the patients.
In the review of literature, coronary angiography was employed in one patient with laughter-induced syncope. Its results revealed no significant coronary artery disease. If there is suspicion for an arrhythmogenic cause of syncope, an electrophysiology (EP) study is sometimes also done to rule it out. No previous case reports have done an EP study on a patient with laughter-induced syncope.
The Bezold-Jarisch Reflex has been proposed to explain the mechanism behind laughter-induced syncope. Intense laughter causes episodes of prolonged forced expiration against a closed glottis, resulting in decreased lung volume and elevated intrathoracic pressure. The increase in intrathoracic pressure, decreases venous return to the heart, activating baroreceptors that inturn reduce sympathetic activity and heighten parasympathetic cardiovascular tone. These lead to hypotension and bradycardia that result in sudden cerebrovascular hypo perfusion and subsequent loss of consciousness.7
*CABG- coronary artery bypass graft; *N-normal; *EF-ejection fraction
The treatment of situational syncope mostly involves avoidance of triggers or instances that elicit the transient loss of consciousness. It also involves identifying prodromal symptoms and adapting protective postures such as being in a supine position with legs raised. Maneuvers can also be employed to try to halt the attacks through physical counter-pressure measures such as tensing the arms with clenched fists and leg crossing. Being a subtype of vasovagal syncope, laughter-induced syncope is medically managed in the same way as vasovagal syncope. Of all the interventions, there is currently no available evidence to support any form of treatment employed for vasovagal syncope. Support stockings, volume expansion through liberal fluid and salt intake, beta-blockers and, the vasopressor, midodrine are commonly employed. These measures may ameliorate the frequency of syncope, however, sufficient evidence to support them are lacking.1-8
In laughter-induced syncope cases found in literature, the most common therapy employed is advising patients to curtail their laughter. For those who have contributing medical illness, addressing the underlying problem has been curative. Examples are stenting of brachiocephalic stenosis, surgical resection of ependymoma, and bypass of carotid stenosis. Reflex-mediated syncopes like laughter syncope are benign. Unless there is an underlying cardiac or neurologic abnormality, patients are healthy and have good prognosis.CONCLUSION
In conclusion, a large number of episodes of syncope have an unknown etiology. History, physical exam and ECG are important for arriving at a diagnosis. Cardiac evaluation is useful in ruling-out cardiac causes that might suggest a poor prognosis. Situational syncope can be diagnosed by history alone and investigational tests usually yield negative results.AUTHOR CONTRIBUTIONS
Biso S, Wongrakpanich S, Agrawal A, Yadlapati S, Kishlyansky M and De Venecia T all contributed to the literature review and writing of the manuscript.ACKNOWLEDGEMENT
The authors would like to thank Dr. Chitra Punjabi at Einstein Medical Center, Philadelphia, Pennsylvania, for assistance with article preparation.ABBREVIATIONS USED
*CABG- coronary artery bypass graft; *N-normal; *EF-ejection fraction.REFERENCES