Laughter-induced syncope is an unusual but recognized form of situational syncope

Syncope (medicine)

Syncope , the medical term for fainting, is precisely defined as a transient loss of consciousness and postural tone characterized by rapid onset, short duration, and spontaneous recovery due to global cerebral hypoperfusion that most often results from hypotension.Many forms of syncope are...

 (fainting) likely to have a similar pathophysiological origin to tussive syncope. One case report occurred while watching the television show Seinfeld, and was given the name Seinfeld syncope.

There are few case reports of this syndrome in the literature. Patients, as in this case, might present initially to the ED, and laughter

Laughter

Laughing is a reaction to certain stimuli, fundamentally stress, which serves as an emotional balancing mechanism. Traditionally, it is considered a visual expression of happiness, or an inward feeling of joy. It may ensue from hearing a joke, being tickled, or other stimuli...

 should be considered among the numerous differentials for syncope.

Laughter-induced syncope should not be confused with cataplexy

Cataplexy

Cataplexy is a sudden and transient episode of loss of muscle tone, often triggered by emotions. It is a rare disease , but affects roughly 70% of people who have narcolepsy...

, a sudden loss of muscle tone triggered by strong emotions, particularly laughter. Unlike syncope, there is no loss of consciousness in cataplexy, which affects some sufferers of narcolepsy

Narcolepsy

Narcolepsy is a chronic sleep disorder, or dyssomnia, characterized by excessive sleepiness and sleep attacks at inappropriate times, such as while at work. People with narcolepsy often experience disturbed nocturnal sleep and an abnormal daytime sleep pattern, which often is confused with insomnia...

.

To date there have been few cases of laughter-induced syncope documented in medical literature.