Termed singultus and caused by synchronous contractions of the diaphragmatic and intercostals muscle followed by the sudden closure of the glottis.
The hiccup reflex is related to the afferent pathway to the vagal and phrenic nerves and the sympathetic chain, the hypothalamic central hiccup center, and the efferent pathway through the phrenic nerve to the diaphragm and the accessory nerve to the intercostal muscles.
Irritation of the phrenic nerve can lead to the hiccup reflex.
Neurotransmitters GABA and dopamine are involved.
Benign and affects everyone from time to time.
When inspired air meets the closed glottis the noise of a hiccup is appreciated.
Classified as transient (lasting less than 24 hours), persistent (lasts up to 1 month), and chronic (lasting more than 1 month).
Transient type is benign and at times may be physiological.
Most episodes are transient and require no treatment.
Chronic type is rare with an estimated prevalence of 1 in 100,000 individuals.
Chronic hiccups can lead to impaired nutrition, weight loss, fatigue and debility.
Chronic hiccups increased in males while transient and persistent affect genders equally.
May be persistent and sign of serious underlying disease.
Persistent/intractable process has been reported in up to 10% of patients with advanced cancer .
In patients on mechanical ventilation they can trigger a full respiratory cycle resulting in respiratory alkalosis.
Causes include gastric distention, carbonated beverages, air swallowing, overheating, sudden temperature changes of hot to cold liquids, hot then cold shower, alcohol ingestion, and states of heightened emotion.
Central nervous system disorders include infections, strokes, trauma, and neoplasms.
Metabolic causes include hyperventilation and uremia.
Irritation of the vagus or phrenic nerve from head and neck foreign bodies, goiters, and neoplasms may be responsible.
When prolonged can cause sleep disturbances, fatigue, exhaustion, reduced food and fluid intake, possible aspiration, emotional distress, and decreased cognitive function.
Thoracic problems including pneumonia, neoplasms, empyema, pericarditis, aneurysms, esophageal obstruction, reflux esophagitis, and myocardial infarction may also be causes.
Abdominal causes include subphrenic abscess, hepatitis, hepatomegaly, cholecystitis, gastric distention, stomach neoplasm, pancreatitis, and pancreatic malignancy.
It may follow postoperative status and general anesthesia.
May be caused by low levels of seum sodium, calcium, potassium, hyperglycemia, sudden changes of temperature, alcohol intake, stroke, brain tumors, and head injuries.
The evaluation for persistent hiccups include a neurologic examination, chemistry evaluation and a chest x-ray.
If diagnosis remains unclear patient may require CAT scans of the head and neck, chest, abdomen, upper G.I. endoscopy, bronchoscopy or echocardiography.
Associated with chemotherapy agents including cisplatin, cyclophosphamide, carboplatinum, docetaxel, paclitaxel, etoposide, gemcitabine, and vinorelbine.
Other agents reported to cause problems hiccups include steroids, benzodiazepines, methyldopa, barbituates, heroin, nicotine, antibiotics, and inhaled anesthesia.
Treatment may include: irritation of the nasopharynx by traction on the tongue, or by catheter stimulation of the nasopharyngeal, elevation of the uvula, eating dry granulated sugar, breath holding to interrupt the respiratory cycle, Valsalva maneuver, sneezing, rebreathing into a bag, frightening stimulus, and relief of gastric distention.
Drug agents useful include chlorpromazine, olanzapine, anticonvulsant agents such as phenytoin, benzodiazepines, metoclopramide, baclofen, gabapentin, haloperidol, carvedilol, midazolam, valproic acid, carbamezine, amantadine, nebulized lidocaine and rarely, general anesthesia.
Chlorpromazine Is the only FDA approved agent.