Located underneath the lungs, the diaphragm is a muscle that contracts every time a person takes a breath. This contraction causes the diaphragm to drop down, allowing the lungs to expand and take in air. Hiccups occur when the diaphragm suddenly contracts at other times. Shortly after the contraction begins, the vocal cords abruptly close, producing the typical hiccup sound. While hiccups usually occur during or shortly after eating, they sometimes develop at other times. Hiccups during sleep may be caused by eating or drinking near bedtime, an underlying medical disorder or certain medications.
Bed-time Eating and Drinking
When a large meal is consumed, the stomach expands and becomes distended. The stomach may then press up on the diaphragm, causing it to contract. In this way, eating a large meal near bedtime can produce hiccups. Drinking a large amount of carbonated drinks at bedtime can also cause hiccups, as the air in these drinks can distend the stomach. Consuming a large amount of alcohol before going to bed is another possible cause of hiccups during sleep. The excessive amount of alcohol can cause the stomach to distend. In addition, alcohol is an irritating substance, which may stimulate nerves in the lining of the stomach that lead to reflex contractions of the diaphragm.
Gastroesophageal Reflux Disease
Gastroesophageal reflux disease (GERD) may also produce hiccups. In this disorder, liquid travels from the stomach back up into the esophagus -- the foodpipe that normally leads food and liquid in the other direction, from the throat to the stomach. Stomach liquid is an acid, which is irritating to the esophagus. This acid may stimulate nerves in the lining of the esophagus that produce reflex contractions of the diaphragm. Reflux of gastric contents often occurs during sleep, especially if a person eats a large meal shortly before bedtime and sleeps in a flat position, without raising the head of the bed.
Other Medical Disorders
A number of diseases may cause hiccups that can occur at any time of the day, including during sleep. Hiccups may occur with many brain disorders, including strokes, brain tumors, multiple sclerosis, Parkinson disease or brain injuries. People with these conditions will usually have other neurological symptoms as well. Any disorder that causes stomach distention can also produce hiccups. Disorders of the neck and throat, such as tumors or an enlarged thyroid, can stimulate nerves that cause reflex contractions of the diaphragm. Hiccups may also be produced by inflammation or infection near the diaphragm, which may be caused by such disorders as pleurisy -- inflammation of the covering around the lungs -- or pneumonia in the lower parts of the lungs. Hiccups sometimes occur with heart attacks. Disorders causing widespread abnormalities of nerve function, such as decreased kidney function, electrolyte abnormalities and diabetes, may also produce hiccups.
A large number of medications may cause hiccups. Medications taken only at bedtime, such as sleep medicine, cause hiccups primarily during sleep. Other medications cause hiccups at other times of the day as well. These are examples of medications that may produce hiccups:
medications: eszopiclone (Lunesta)
- Anti-cancer drugs: fluorouracil, cisplatin, oxaliplatin,
blood pressure medications: methyldopa (Aldomet)
medications: aripiprazole (Abilify)
disease medications: levodopa
disease medications: donepezil (Aricept)
When to Seek Medical Attention
Hiccups that last more than 2 days or occur while sleeping should be assessed by a doctor, as they may be due to a serious medical disorder that requires attention. Treatment of the underlying condition is the best way to get rid of hiccups. When the cause cannot be found, there are several medications that may be prescribed if hiccups are very frequent or interfere with sleep.
Reviewed by: Mary D. Daley, M.D.