Laugh syncope as a rare sub-type of the situational syncopes: a case report

Abstract

Introduction: Laughter is a good medicine; it enhances cardiovascular health and the immune system. What happens, however, if a person laughs too much or the laughter becomes out of control? Laughter-induced syncope is rare and likely goes unrecognized by many health care providers. It is thought to be another form of Valsalva-induced syncope.

Recurrent Laughter-induced Syncope

“…Since the description of laughing syncope by Cox et al, 1 only 15 other cases of laughing (or gelastic) syncope have been published in the literature to the best of our knowledge. [2][3][4][5][6][7][8][9][10][11][12][13][14] Most cases were neurally mediated syncopes triggered by laughter 2-4,6,7,10,12,13 similar to our case. Two individuals had attacks of near syncope only.…”

“…Two individuals had attacks of near syncope only. 12,13 Laughter-induced syncope was a single event in most individuals, 1,2,[4][5][6][7]9,10,13 with only 2 previously reported cases having multiple episodes of laughing syncope. 8,13 A few cases had multiple syncopes also triggered by coughing, defecation, or micturition.…”

“…3 The reflex mechanisms involved in neurally mediated syncope may contribute to syncope in cases with extracranial cerebrovascular disease, 1,14 where an increase in the intrathoracic pressure may compromise the blood flow and cerebral perfusion further. The mechanism in cases with central nervous system involvement 5,9,10 is not known.…”

Laughter-induced syncope

“…Laughter-induced syncope is a rare entity and is thought to be caused by vasovagal mechanisms 1. The increase in intrathoracic pressure reduces venous return to the heart and stimulates the baroreceptors.…”

“…The increase in intrathoracic pressure reduces venous return to the heart and stimulates the baroreceptors. This in turn causes inappropriate parasympathetic tone with stimulation of the vagus nerve, decreasing heart rate with accompanying vasodilatation, and causing a sudden transient decline in cerebrovascular profusion and loss of consciousness 1. Other forms of loss of consciousness with the same mechanism of action are syncope secondary to coughing, sneezing or weightlifting.…”