Description

• Hiccups are caused by a repetitive sudden involuntary contraction of the inspiratory muscles (predominantly the diaphragm) with the abrupt closure of the glottis, which stops the inflow of air and produces a characteristic sound.
• Hiccups are classified based on their duration: Hiccup bouts last up to 48 hours; persistent hiccups last >48 hours but <1 month; intractable hiccups last for >1 month.
• System(s) affected: nervous, pulmonary
• Synonym(s): hiccoughs; singultus

Geriatric Considerations
Can be a serious problem, particularly among the elderly

Pregnancy Considerations

• Fetal hiccups are rhythmic fetal movements (confirmed sonographically) that can be confused with contractions.
• Fetal hiccups are a sign of normal neurologic development.

Epidemiology

• Predominant age: all ages (including fetus)
• Predominant sex: male > female (4:1)

Incidence
Overall incidence in the general population is uncertain.

Prevalence
Self-limited hiccups are extremely common, as are intraoperative and postoperative hiccups.

Etiology and Pathophysiology

• 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 and brain (1)
• In men, >90% have an organic basis; in women, psychogenic causes are more common.
• Specific underlying causes include the following:
  • CNS disorders: vascular lesions (AV malformation), infectious causes (meningitis, encephalitis), structural lesions (intracranial/brainstem mass lesions, multiple sclerosis, hydrocephalus, syringomyelia), posterior inferior cerebellar artery (PICA) aneurysm; seizure disorder
  • Diaphragmatic irritation (tumors, pericarditis, eventration, splenomegaly, hepatomegaly, peritonitis)
  • Irritation of the tympanic membrane
  • Nerve irritation: pharyngitis, laryngitis, neck tumors
  • 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)
  • Gastrointestinal (GI) disorders (gastritis, GERD, PUD, distention, cancer)
  • Hiccups have been reported as an initial presentation of COVID-19.
  • Cardiovascular disorders (MI, pericarditis)
  • Hepatic lesions (hepatitis, hepatoma); pancreatic lesions (pancreatitis, pseudocysts, cancer)
  • Inflammatory bowel disease; cholelithiasis, cholecystitis
  • Prostatic disorders
  • Appendicitis; postoperative, particularly with abdominal procedures
  • Metabolic causes (uremia, hyponatremia, gout, diabetes)
  • Drug-induced (dexamethasone, methylprednisolone, anabolic steroids, benzodiazepines, α-methyldopa, propofol, levofolinate, oxaliplatin, fluorouracil, carboplatin, cisplatin, tramadol)
  • Toxic (alcohol-induced)
  • Psychogenic causes (anorexia, conversion, grief, malingering, schizophrenia, stress)
  • Idiopathic

Risk Factors

• Overeating
• Consuming carbonated beverages
• Excessive alcohol consumption
• Excitement or emotional stress
• Changes in ambient or GI temperature

General Prevention

• Identify and correct relevant underlying cause(s).
• Avoid gastric distention.
• Acupuncture shows promise compared to chronic drug therapy for controlling hiccups.