Hiccups are repeated involuntary spasms of the diaphragm followed by sudden closure of the glottis, which checks the inflow of air and causes the characteristic sound. Transient episodes are very common. Persistent (> 2 days) and intractable (> 1 mo) hiccups are uncommon but quite distressing.
Hiccups follow irritation of afferent or efferent diaphragmatic nerves or of medullary centers that control the respiratory muscles, particularly the diaphragm. Hiccups are more common among men.
Cause is generally unknown, but transient hiccups are often caused by the following:
Persistent and intractable hiccups have myriad causes (see Table: Some Causes of Intractable Hiccups).
Some Causes of Intractable Hiccups
History of present illness should note duration of hiccups, remedies tried, and relationship of onset to recent illness or surgery.
Review of systems seeks concomitant GI symptoms such as gastroesophageal reflux and swallowing difficulties; thoracic symptoms such as cough, fever, or chest pain; and any neurologic symptoms.
Past medical history should query known GI and neurologic disorders. A drug history should include details concerning alcohol use.
Few findings are specific. Hiccups after alcohol consumption or surgery may well be related to those events. Other possible causes (see Table: Some Causes of Intractable Hiccups) are both numerous and rarely a cause of hiccups.
No specific evaluation is required for acute hiccups if routine history and physical examination are unremarkable; abnormalities are pursued with appropriate testing.
Patients with hiccups of longer duration and no obvious cause should have testing, probably including serum electrolytes, BUN and creatinine, chest x-ray, and ECG. Upper GI endoscopy and perhaps esophageal pH monitoring should be considered. If these are unremarkable, brain MRI and chest CT may be done.
Identified problems are treated (eg, proton pump inhibitors for gastroesophageal reflux disease, dilation for esophageal stricture).
For symptom relief, many simple measures can be tried, although none are more than slightly effective: PaCO2 can be increased and diaphragmatic activity can be inhibited by a series of deep breath-holds or by breathing deeply in to and out of a paper bag. (Caution: Plastic bags can cling to the nostrils and should not be used.) Vagal stimulation by pharyngeal irritation (eg, swallowing dry bread, granulated sugar, or crushed ice; applying traction on the tongue; stimulating gagging) may work. Numerous other folk remedies exist.
Persistent hiccups are often recalcitrant to treatment. Many drugs have been used in anecdotal series. Baclofen, a gamma-aminobutyric acid agonist (5 mg po q 6 h increasing to 20 mg/dose), may be effective. Other drugs include chlorpromazine 10 to 50 mg po tid prn, metoclopramide 10 mg po bid to qid, and various anticonvulsants (eg, gabapentin). Additionally, an empiric trial of proton pump inhibitors may be given. For severe symptoms, chlorpromazine 25 to 50 mg IM or IV can be given. In intractable cases, the phrenic nerve may be blocked by small amounts of 0.5% procaine solution, with caution being taken to avoid respiratory depression and pneumothorax. Even bilateral phrenicotomy does not cure all cases.