Hiccups - Causes of hiccups

Hiccups occur when your diaphragm (the thin layer of muscle that separates your chest cavity from your abdomen) suddenly and involuntarily contracts (tightens).

As your diaphragm contracts, it causes you to breathe air in very quickly. The incoming air is stopped when your glottis (the opening between your vocal cords) closes suddenly, producing the characteristic sound of a hiccup.

Causes of short-term hiccups

Most cases of hiccups occur for no apparent reason. Everyone experiences a short bout of hiccups from time to time. This is perfectly normal and nothing to be concerned about.

In some cases however, short-term hiccups may appear to have a specific trigger, such as:

drinking alcohol
smoking
having a bloated stomach
eating too quickly or eating spicy foods
drinking hot or fizzy drinks
swallowing air – for example, while chewing gum
a sudden change in room temperature
a sudden change in the temperature inside your stomach – for example, eating something hot followed by a cold drink
emotions, such as stress, fear or excitement

People experiencing short-term hiccups usually pass without the need for treatment.

Causes of long-lasting hiccups

In rare cases, hiccups that last 48 hours or longer can be caused by an underlying condition or a medication you are taking, although in many cases a cause is not identified.

Underlying conditions

Some of the conditions that can cause long-term hiccups include:

gastrointestinal conditions – such as gastro-oesophageal reflux disease (GORD), inflammatory bowel disease (IBD) or a small bowel obstruction
respiratory conditions – such as asthma, pneumonia or pleurisy
conditions affecting the central nervous system – such as stroke, a tumour affecting the brain, encephalitis or a traumatic brain injury
a condition irritating the vagus nerve (a nerve that controls the diaphragm) – such as goitre, pharyngitis or meningitis
a psychological reaction – such as shock, fear, grief, excitement, or stress
conditions involving your metabolism (the way your body digests food) – such as diabetes, hypoglycaemia or hyperglycaemia

Medication

Persistent hiccups can sometimes also be caused by a reaction to certain types of medication, such as:

anaesthesia – medication given before a surgical operation or procedure that causes a loss of sensation or consciousness
corticosteroids – medication that reduces inflammation (swelling)
benzodiazepines – a type of sedative that helps to reduce anxiety
barbiturates – a type of sedative sometimes used to prevent seizures (fits)
opioids – medication used to treat pain; morphine and methadone are both strong opioids
methyldopa – medication used to treat high blood pressure (hypertension)
chemotherapy medications – medicines used to kill cancer cells

If an underlying cause of long-lasting hiccups can be identified, treating this cause can help improve the problem.