Hiccup

Hiccup, also spelled hiccough, is a sudden, involuntary contraction of the diaphragm followed by a rapid closure of the vocal cords, producing the characteristic “hic” sound. The hiccup reflex involves a neural circuit that includes the phrenic and vagus nerves and various parts of the brainstem.

Most hiccups are brief and harmless, lasting only minutes to hours. They can be caused by irritation or stimulation of the diaphragm or its nerves, rapid stomach distension, or brief imbalances in respiratory control. Common triggers include eating or drinking too quickly, carbonated beverages, alcohol, sudden changes in stomach temperature, excitement or stress, and laughter. Hiccups are also common in newborns and young infants, often resolving without treatment.

Classification and causes: Hiccups are generally categorized as acute if they last less than 48 hours, persistent if they last longer than 48 hours, and intractable if they continue for more than about a month. Persistent or intractable hiccups may reflect underlying conditions such as gastroesophageal reflux, central nervous system disorders, metabolic abnormalities, kidney or liver disease, or injury or irritation of the phrenic or vagus nerves, and may be medication-induced.

Diagnosis and management: Most cases require no investigation beyond medical history and physical examination. When hiccups persist, clinicians may evaluate for underlying causes with laboratory testing, imaging, or specialized studies and treat the underlying condition. For symptom relief, common but evidence-limited remedies include breath-holding, slow breathing, sipping cold water, swallowing sugar, or gentle tongue traction. If persistent or intractable, treatments such as chlorpromazine are considered, with alternatives including baclofen, gabapentin, or metoclopramide; in rare cases, nerve stimulation or injections may be used.

History and etymology: The term hiccup derives from the English word hiccup, with hiccough a longer form used in British English; both reference the characteristic sound. In medical literature, the reflex mechanism is described as the hiccup reflex.