Hiccup

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[edit] Hiccup

John Noble

Hiccup is a complex reflex action. The hiccup reflex appears to be generated from a locus in the medullary reticular formation, the hiccup-evoking site, where stimuli produce both a powerful diaphragmatic contraction and a temporal suppression of the posterior cricoarytenoid muscles, causing closure of the glottis. Spasms may occur 40 to 100 times per minute. The majority occur unilaterally involving the left hemidiaphragm. Afferent impulses are carried by the vagus nerves and the dorsal afferent sympathetic nerves (T10-T12) from the diaphragm to the hiccup center. Efferent impulses are believed to be carried from the center to the diaphragm by the phrenic nerve, formed by branches from the fourth cervical segment and smaller branches from the third, fifth, and sixth segments. Hiccups may be produced by stimuli applied at any site located along the phrenic nerve or diaphragm. The reflex pathways are similar to pathways that produce coughing, sneezing, swallowing, and vomiting.

[edit] History And Physical Examination.

Hiccups occur commonly and, in the vast majority of cases, are transient. Cessation occurs spontaneously or may be facilitated by mechanical or medical treatments. Etiologic factors in 220

hiccup patients reported from the Mayo Clinic revealed that five times as many men were afflicted as women, and a large proportion of the men had associated medical or surgical problems.^[1] In this study, transient hiccup in women and in a smaller percentage of men appeared to be caused by (or were associated with) psychologic or stress-related factors.

A medical history should include history of stroke; recent neurologic, chest, or abdominal surgery; renal failure; dialysis; or ingestion of new medications. The history must be detailed, including dietary and medication histories. For example, a small number of patients on renal hemodialysis have been reported to develop persistent hiccup after eating star fruit, which is reported to contain a hiccup-producing excitatory neurotoxin.^[2] Treatment with dexamethasone has also been reported to cause untreatable hiccups.^[3] Hiccups are also commonly encountered among older adults during rehabilitation following a stroke.

The history and physical examination should be focused on identifying any potential abnormalities that could interfere with normal neural transmissions along the complex pathways that are part of the hiccup reflex. Lesions of the tympanic membrane, pharynx, neck, chest, diaphragm, pericardium, gallbladder, esophagus, and stomach must all be suspected (Box 23-1).

[edit] Laboratory.

Laboratory examinations are not indicated for patients with transient hiccups. If hiccups are recurrent or intractable, however, a careful laboratory evaluation is critically important unless the probable etiology is evident (see A). Tests should include electrolytes, blood urea nitrogen (BUN), creatinine, and chest x-ray. A computed tomography (CT) scan of the abdomen and chest should be obtained to identify possible lesions that may be compressing the diaphragm or neural pathways connecting it with the medulla. If hiccups are intractable, a magnetic resonance imaging (MRI) scan may reveal occult neuropathology. In patients with strokes, MRI scans of the brain have identified lesions in the pons and other locations that have contributed to hiccups, aspiration pneumonia, malnutrition, and respiratory arrest.^[4]

[edit] Nonpharmacologic Treatment.

Treatment for hiccup may be divided between traditional methods for terminating transient hiccup and various therapies, including pharmacologic and nonpharmacologic, for persistent or intractable hiccup. These treatments are appropriate for transient hiccup and may be tried in patients with intractable hiccup. Many physicians, however, will use pharmacologic therapy as a first choice for treating intractable hiccup. A few of the many nonpharmacologic treatments include breath holding; breathing into a paper bag; stimulating gagging by swallowing dry granulated sugar, lifting the uvula with a spoon, or drinking water from the wrong side of a cup; gargling; and passing a nasopharyngeal catheter.

[edit] Medical Therapy.

Persistent, intractable hiccup may present a major therapeutic challenge. Many different medications have been prescribed for the control and termination of this condition.^[5] Recent best evidence suggests that a majority of patients will respond to one or combinations of the following three regimens^[6]:

• Cisapride (Propulsid) and/or omeprazole (Prilosec) to reduce gastric acid production and facilitate gastric emptying through blocking afferent input. Dosage: cisapride 10 mg po 15 min before meals and hs, or omeprazole 20 to 40 mg po qd.
  
• Baclofen (Lioresal), an antispasmodic, reduces excitability as a γ-aminobutyric acid agonist and depresses reflex activity. Dosage: 5 to 20 mg po q6-12h.
  
• Chlorpromazine (Thorazine), a major tranquilizer, is often effective in treating hiccup. Dosage: 25 to 50 mg IV q6h; if successful, switch to po route with same dose.
  

[edit] Consultation.

Intractable hiccup is a complex and difficult disorder. Consultation based on the individual medical circumstances is in order when initial medical therapy is not effective or when complex drug regimens and interventions designed to modulate, stimulate, or oblate the phrenic or vagus nerve are being considered. Neurologic consultation is most often engaged unless intraabdominal problems are present, in which case gastroenterology consultation may be helpful.

[edit] REFERENCES