Hiccups
Hiccups (or hiccoughs), medical term singultus (rarely used), are an unpleasant phenomenon, experienced by everyone on occasion, and usually self-limiting. However the much rarer intractable chronic form can be extremely debilitating.
Epidemiology
Hiccups are a symptom that has probably been experienced by everyone at some point in their lives. Chronic intractable hiccups are rare.
Clinical presentation
Acute hiccups are those lasting less than 48 hours, and are usually self-limiting.
Chronic, persistent hiccups refers to any episode with a duration greater than 48 hours. Intractable hiccups, sometimes defined as those lasting more than two months, can be very disabling, causing inability to sleep, depression, and chronic exhaustion, with secondary deleterious effects on an individual's health.
Pathology
Curiously for such a common, everyday phenomenon, the direct cause and pathogenesis of this symptom remains unknown.
The currently accepted hypothesis is that hiccups occur secondary to dysfunction of the swallowing reflex arc, of which there are three main components :
- nerves within the phrenic and vagus nerves, and also the thoracic sympathetic chain
- least understood portion
- likely involvement of the brainstem and hypothalamus
- nerve supply to the responsible musculature including the diaphragm, anterior scalenes, intercostals, and glottis
Neurotransmitters implicated include GABA and dopamine.
Etiology
Acute hiccups
- sudden/marked gastric distension e.g. large meal, carbonated beverages
- alcohol
- smoking
- psychogenic factors
Chronic hiccups
More than 100 causes have been identified :
- idiopathic
- psychogenic
- gastrointestinal
- diaphragmatic pathology
- hernia
- neoplasm
- esophageal malignancy
- esophagitis
- diaphragmatic pathology
- infection
- iatrogenic
- anesthesia-related
- neurological
- head injury
- meningoencephalitis
- CNS malignancy
- multiple sclerosis
- stroke
- metabolic/endocrine
- diabetes mellitus
- electrolyte disturbances e.g. hyponatremia, hypokalemia, hypocapnia
- ethanol excess
- pharmacological
- barbiturates
- benzodiazepines e.g. diazepam
- methyldopa
- steroids e.g. dexamethasone
Radiographic features
The features of the underlying causes are described in their respective articles.
Treatment and prognosis
Folk remedies abound for the treatment of acute hiccups.
Initially therapy is directed to the specific cause.
In addition for the more serious chronic intractable form there are pharmacological and non-pharmacological interventions.
History and etymology
Singultus is the Latin for sobbing, gasping.