Description

• Hiccups are caused by a sudden involuntary contraction of the inspiratory muscles (predominantly the diaphragm) terminated by abrupt closure of the glottis, stopping the inflow of air and producing the characteristic sound (1).
• System(s) affected: Nervous; Pulmonary
• Synonym(s): Hiccoughs; Singultus

Geriatric Considerations
Can be a serious problem among the elderly

• Fetal hiccups are noted as rhythmic fetal movements (confirmed sonographically) that can be confused with contractions.
• Fetal hiccups often recur in subsequent pregnancies.

Epidemiology

• Predominant age: All ages (including fetus)
• Predominant sex: Male > Female (4:1)

Prevalence
Self-limited hiccups are extremely common, as are intra- and postoperative hiccups; intractable hiccups are rare.

Risk Factors

• General anesthesia; conscious sedation
• Postoperative state
• Genitourinary disorders
• Irritation of the vagus nerve branches
• Structural, vascular, infectious, neoplastic, or traumatic CNS lesions

General Prevention

• Identify and correct the underlying cause.
• Avoid gastric distention.
• Seek medical attention for frequent bouts or persistent hiccups.
• Acupuncture appears to be as or more efficacious than chronic drug therapy to control hiccups.

Etiology

• Pathophysiologic significance is unknown; may be a vestigial reflex; hiccups have been associated with >100 underlying disorders (1). The latest theory suggests hiccups function to remove swallowed gas from the stomach as a burping reflex (2)
• Results from stimulation of ≥1 limbs of the hiccup reflux arc (vagus and phrenic nerves) with a “hiccup center” located in the upper spinal cord
• In men, >90% have an organic basis, whereas in women a psychogenic cause may be more likely.
• Specific underlying causes include:
  • Alcoholism
  • CNS lesions (brain-stem tumors, vascular lesions, Parkinson disease) (3)
  • Diaphragmatic irritation (tumors, pericarditis, eventration, splenomegaly, hepatomegaly, peritonitis)
  • Hair, insect, or foreign body irritating tympanic membrane
  • Pharyngitis, laryngitis
  • Mediastinal and other thoracic lesions (pneumonia, aortic aneurysm, tuberculosis [TB], myocardial infarction [MI], lung cancer, rib exostoses)
  • Esophageal lesions (reflux esophagitis, achalasia, Candida esophagitis, carcinoma, obstruction)
  • Gastric lesions (ulcer, distention, cancer)
  • Hepatic lesions (hepatitis, hepatoma)
  • Pancreatic lesions (pancreatitis, pseudocysts, cancer)
  • Inflammatory bowel disease
  • Cholelithiasis, cholecystitis
  • Prostatic disorders
  • Appendicitis
  • Postoperative, abdominal procedures (4)
  • Toxic metabolic causes (uremia, hyponatremia, gout, diabetes)
  • Drug-induced (dexamethasone, methylprednisolone, anabolic steroids, benzodiazepines, α-methyldopa, propofol)
  • Psychogenic causes (hysterical neurosis, grief, malingering)
  • Idiopathic

Commonly Associated Conditions

See “Etiology.”