It is thought that a number of specific nerves in the spinal cord at the back of the neck control hiccups. When something triggers these nerves - eating too quickly, for example - a signal is sent to the phrenic nerve, which controls the diaphragm. The diaphragm signals back to the hiccup center and hiccups begin. Within a split second, a structure called the glottis closes off the windpipe, producing the characteristic sound of a hiccup.
Hiccups, or hiccoughs as some people call them, is a mystery ailment with no known purpose. In general, they almost always pass within minutes. In rare cases, they last for a few days.
Usually, hiccuping is an entirely benign, if annoying, phenomenon. Any number of mundane circumstances can set off a bout in susceptible people. Perhaps the most common trigger is swallowing air, usually from eating too fast, chewing gum, or drinking carbonated beverages.
Some people hiccup in response to alcohol or spicy foods and drinks. Stress and excitement also are possible instigators.
Everyone has a pet remedy for hiccups. A few tactics do make sense and may be based on physiology as well as folklore. One technique is to increase carbon dioxide levels in the blood, which may decrease the sensitivity of the vagus nerve in the brain. That nerve, one of the longest in the body, sends branches to many muscle groups, including those in the diaphragm. One can boost carbon dioxide levels by holding one's breath, by rebreathing the air exhaled into a paper bag for a few minutes, or by slowly sipping a glass of water without pausing to take a breath.
Other tactics that may be of some use include:
- placing a teaspoon of dry granulated sugar on the back of the tongue and then swallowing it
- filling a glass with ice cubes and water, and then drinking it slowly (the rapid change of temperature in the esophagus may shut down the hiccup response)
- pulling the tongue with your fingers
- stimulating the back of the throat or roof of the mouth with the index finger
- while sitting, leaning forward and compressing the chest and diaphragm against the knees
If no underlying cause can be quickly found and corrected, medical intervention can end the suffering. A physician may pass a tube through the nose into the stomach to release trapped air, stimulating the back of the throat at the same time. Various medications may help, including the tranquilizers chlorpromazine (Thorazine) and diazepam (Valium), as well as antispasmodic metoclopramide (Reglan), and the muscle relaxant baclofen. Sometimes, local anesthetics like lidocaine are used to numb the back of the throat.
Serious hiccups can be complicated to treat. The doctor's first job is to look for possible underlying illnesses. A number of lung ailments, including asthma and bronchitis, can lead to persistent hiccups, as can many disorders of the bowels, liver, and kidneys.
If an illness is found, treating it usually halts the hiccups. If no illness can be detected, the doctor may attempt one or more of a wide variety of therapies.
Many of the treatments are aimed at stimulating the nerves in the back of throat, in hopes of interrupting the hiccup cycles. The doctor may pull on the tongue, for example, or use a spoon to lift the uvula, the small structure at the back of the throat that hangs from the top of the mouth. Sometimes, ice, electrical stimulation, or a local anesthetic is applied to the back of the throat.
Other treatments are aimed at stimulating the diaphragm, the flat muscle that separates the chest from the abdomen. These include applying pressure to certain points below the hiccuping patient's rib cage, or having sufferers draw their knees up to their chests.
Although many drugs have been tried, none has proved consistently effective. The drugs include antiseizure medications, antidepressants, tranquilizers and sedatives. Two drugs frequently prescribed at present for serious hiccups include chlorpromazine, an antipsychotic medication used to treat schizophrenia and other mental illnesses, and metoclopramide, used to control a variety of gastrointestinal problems.
If persistent hiccups last for more than 48 hours, a doctor's assistance should be sought.
Cause For Concern
Several serious underlying diseases are linked with hiccups and should be investigated if the hiccups are persistent, chronic, interfere with work, eating, or sleep, or are associated with weight loss. Lung tumors, pneumonia, gastroesophageal reflux, and even a heart attack are sometimes accompanied by hiccups.