Stimulus and site specific induction of hiccups in the oesophagus of normal subjects.

BACKGROUND Hiccups that are induced by a large meal have been suggested to result from gastric overdistension. The role of the oesophagus in precipitating hiccups has never been defined. AIMS To determine the involvement of oesophageal mechanoreceptors in the hiccup reflex. METHODS Ten normal healthy subjects were prospectively evaluated at a university affiliated hospital. Controlled inflation of a polyethylene bag in the proximal and distal oesophagus was carried out using slow ramp and rapid phasic distensions, by an electronic distension device. RESULTS Hiccups were induced in four subjects only during rapid phasic distensions and only in the proximal oesophagus. The mean (SEM) minimal volume threshold for the hiccup reflex was 32.5 (4.8) ml, which was above the perception threshold. Hiccups appeared during inflation and resolved after deflation. CONCLUSIONS Sudden rapid stretch of the mechanoreceptors in the proximal oesophagus can trigger the hiccup reflex in normal subjects. Only rapid distensions above a determined volume threshold will predictably induce hiccups in a given subject. This mechanism may play a role in the physiological induction of hiccups.