A hiccup is a sudden, involuntary contraction of the diaphragm, the main breathing muscle under the lungs. This sucks air rapidly into the lungs, snapping shut a valve (the glottis) above the voice-box (larynx). This snapping makes the characteristic sound of a hiccup. Hiccups start suddenly, usually happen from 4 to 60 times a minute, and usually last for only a few minutes.

Causes

• Stretching of the stomach after rapid eating, drinking, or swallowing air
• Sudden emotional excitement
• Sudden change of air temperature
• Very hot or cold food or drink

Serious (all very rare):

• Irritation of the diaphragm by infection (e.g. abscess) or cancer spread from elsewhere
• Irritation of the phrenic nerve (which controls the diaphragm) by cancer or chest surgery
• Brain infection or tumour
• Severe kidney failure Severe general infections (e.g. malaria)

Treatment

Treatment is needed only for persistent hiccups. Then anti-spasmodic and anti-epileptic drugs may help the hiccups themselves, but the underlying cause itself must be treated.

Complications

If hiccups are persistent, eating and drinking can be difficult, with risk of inhalation of food or drink. Hiccups can be very exhausting to someone who is ill with one of the rare serious causes.