Hiccups (Singultus)



  • The hiccup (or hiccough) is an onomatopoeic name stemming from the sound made by the abrupt glottic closure following involuntary contraction of the diaphragm and intercostal muscles.
  • The medical term for hiccup is singultus, which stems from the Latin singult, originally used to describe the sharp intake of breath associated with prolonged sobbing.
  • Usually a benign, yet recurrent nuisance
  • Prolonged bouts of hiccups can be indicative of an underlying or serious condition.


  • Fetal hiccups are common in pregnancy, and are frequently felt in the third trimester.
  • Hiccups are a physiologic movement in newborns, who may spend as much as 2.5% of their time hiccupping, which decreases in infancy.
  • There is no seasonal, geographic, racial, or socioeconomic predilection.
  • Persistent (>48 hours) and intractable (>1 month) hiccups more commonly occur in men and adults.

General Prevention

Avoid precipitating factors (e.g., eating rapidly, carbonated beverages, alcohol, tobacco).


  • A hiccup reflex arc has been elucidated through the study of pathologic hiccups.
    • Afferent limb: receptors in the distal esophagus, stomach, and abdominal side of the diaphragm; signals travel through the phrenic nerve, vagus, and sympathetic (T6–T12) chain branches.
    • Central component: the middle and dorsolateral medulla; independent from the respiratory center, the hypothalamus, and the phrenic nerve nuclei
    • Efferent limb: phrenic nerve to the diaphragm; accessory nerves to the intercostal and scalene muscles, glottis structures, and the esophagus
  • Hiccups are often unilateral, involving the left hemidiaphragm.


  • Environmental
    • Associated with a change in the ambient or internal temperature
    • Examples: cold showers, hot/cold beverages
  • Central nervous system
    • Examples: neuromyelitis optica, migraine aura, brainstem lesion, hydrocephalus, VP shunt, meningitis, brain abscess
  • Peripheral nervous system
    • Due to irritation or stimulation of phrenic or vagal nerves
    • GI: aerophagia, gastric insufflation, Gastroesophageal reflux disease (GERD), GI malignancies
    • Thoracic: asthma, goiter, pneumonia
    • CV: pericarditis, pericardial effusion, central catheter migration
  • Toxic-metabolic
    • Examples: alcohol, tobacco, uremia, electrolyte imbalance, thrush
  • Psychogenic
    • Examples: excitement, stress, conversion disorder, anorexia nervosa, secondary gain
  • Medications
    • Examples: opioid, benzodiazepines, chemotherapy, anesthetic agents

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