Hiccups

Hiccups are medically known as synchronous diaphragmatic flutter (SDF) or singultus. A hiccup occurs when the diaphragm suddenly contracts involuntarily, while at the same time the larynx (voice box) contracts too and the glottis closes, effective blocking the flow of air.

In the majority of cases, hiccups resolve on their own within a short space of time. Sometimes, however, they may persist and become a nuisance, impacting on sleep, eating, or everyday life.

The hiccup is an involuntary action involving a reflex arc. Once triggered, the reflex causes a strong contraction of the diaphragm followed about 0.25 seconds later by closure of the vocal cords, which results in the classic "hic" sound.

Hiccups may occur individually, or they may occur in bouts. The rhythm of the hiccup, or the time between hiccups, tends to be relatively constant.

A bout of hiccups, in general, resolves itself without intervention, although many home remedies are often used to attempt to shorten the duration. Medical treatment is occasionally necessary in cases of chronic hiccups.

Sign and symptoms of hiccups include:

• A single or a series of breathing diaphragm spasms, of variable spacing and duration.
• A brief (less than one half second), unexpected, shoulder, abdomen, throat, or full body tremor.
• Hiccups may present as an audible chirp, squeak, "hupp", or if controlled, a quick inhaling gasp, sigh, or sniff.
• Hiccups may present as brief but distracting or painful, frequent or occasional interruptions in normal breathing, with sudden momentary pain of the throat, chest, and/or abdomen.

The causes of hiccups in children and infants are not clearly understood. However, in adults it is usually self-limiting disease. Typical causes include:

• Gastric distention (i.e., from food, alcohol, or air)
• Sudden changes in ambient or gastric temperature
• Use of alcohol or tobacco in excess.

Psychogenic causes (i.e., excitement and stress) also may elicit hiccups.

Persistent or intractable episodes are more likely to result from serious pathophysiologic processes affecting a component of the hiccup reflex mechanism.

Psychogenic conditions associated with hiccups include the following

• Hysteria
• Shock
• Fear
• Personality disorders
• Conversion disorders
• Malingering

Central nervous system (CNS)-related causes of hiccups include the following

• Structural lesions- Congenital malformations, malignancies, or multiple sclerosis
• Vascular lesions
• Infection
• Trauma

Conditions that can give rise to diaphragmatic irritation causing hiccups are as follows

• Hiatal hernia
• Subphrenic abscess or collection
• MI
• Pericarditis

Conditions associated with irritation of the following branches of the vagus nerve irritation can cause hiccups

• Meningeal branches – Meningitis or glaucoma
• Auricular branches - Foreign body or hairs
• Pharyngeal branches - Pharyngitis
• Recurrent laryngeal nerve - Mass lesions in the neck, goiter, or laryngitis
• Thoracic branches - Infection, tumors, esophagitis (ie, reflux), myocardial infarction (MI), asthma, trauma, thoracic aortic aneurysm, or pacemaker lead complications
• Abdominal branches - Tumors,gastric distention, peptic ulcer, abdominal aortic aneurysm, infection, organ enlargement, or inflammation (eg, appendicitis, cholecystitis, pancreatitis,or inflammatory bowel disease)

Procedure- or anesthesia-related causes of hiccups include the following

• Hyperextension of the neck - Stretching the phrenic nerve roots
• Manipulation of the diaphragm or stomach
• Laparotomy
• Thoracotomy
• Craniotomy

Metabolic causes of hiccups include the following

• Hyponatremia
• Hypokalemia
• Hypocalcemia
• Hyperglycemia
• Uremia
• Hypocarbia
• Fever

Drugs associated with hiccups include the following

• Benzodiazepines
• Short-acting barbiturates
• Dexamethasone
• Alpha-methyldopa

The diagnosis of hiccups is on the basis of history and physical examination. The laboratory tests are used to diagnose underlying abnormalities. Like serum electrolytes, renal function tests, liver function tests, amylase, lipase, WBC count, urine, sputum, CSF examination.

Imaging modalities that may be helpful in the workup include the following:

• Chest radiography to identify tumors, detect infection, or assess the thoracic aorta
• Fluoroscopy of diaphragmatic movement to confirm the diagnosis if malingering is suspected or to determine if the diaphragmatic abnormality is unilateral or bilateral before invasive therapy
• Computed tomography (CT) of the head, thorax, and abdomen to identify tumors, infection, or structural lesions
• Magnetic resonance imaging (MRI) to detect multiple sclerosis or evaluate vascular relations to the vagus and phrenic nerves.

Other diagnostic tests include:

• ECG to detect cardiac abnormalities,
• nerve conduction studies,
• endoscopy,
• bronchoscopy,
• esophageal reflux tests.

Hiccups are treated medically only in severe and persistent (termed "intractable") cases.

Many drugs have been used: baclofen, chlorpromazine,metoclopramide, gabapentin, and various proton-pump inhibitors.

Hiccups that are secondary to some other cause like gastroesophageal reflux disease or esophageal webs are dealt with by treating the underlying disorder. The phrenic nerve can be blocked temporarily with injection of 0.5% procaine, or permanently with bilateral phrenicotomy or other forms of surgical destruction. Even this rather drastic treatment does not cure some cases, however.

Another medical approach is to install lidocaine liniment 3% or gel 2% into the ear canal. This creates a vagus nerve-triggering reflex through its extensions to the external ear and tympanus (ear drum). The effect can be immediate, and also have lasting effect after the lidocaine effect expires after about two hours.

Haloperidol (Haldol, an anti-psychotic and sedative), metoclopramide (Reglan, a gastrointestinal stimulant), and chlorpromazine (Thorazine, an anti-psychotic with strong sedative effects) are used in cases of intractable hiccups. Effective treatment with sedatives often requires a dose that renders the person either unconscious or highly lethargic. Hence, medicating with sedatives is only appropriate short-term, as the affected individual cannot continue with normal life activities while under their effect.

Persistent digital rectal massage has also been proven effective in terminating intractable hiccups.

The administration of intranasal vinegar was found to ease the chronic and severe hiccups of a three-year-old Japanese girl. Vinegar may stimulate the dorsal wall of the nasopharynx, where the pharyngeal branch of the glossopharyngeal nerve (the afferent of the hiccup reflex arc) is located.

Although hiccups could never really be prevented, there are certain things that can be done to treat or decrease the frequency of their attacks. Among these are avoiding the common triggers of hiccups like eating spicy foods or large meals and drinking alcohol.

Even eating quickly, sudden temperature changes, and smoking cigarettes are considered hiccup triggers that should be avoided to lessen hiccup attacks. Others also include speaking while eating and not chewing your food well.

Aside from avoiding all these things, there are actually a number of measures that can be done against hiccup attacks and here are some of them:

• Lift the uvula or the fleshy tag that can be seen hanging at the back of the mouth’s roof by using a teaspoon.
• Pull your tongue with considerable force.
• Hold your breath for as long as it is still comfortable, then swallow as soon as you feel a hiccup coming on.
• Tickle your mouth’s roof, right at the point near the back where the hard roof becomes softer, using a bud made of cotton wool.
• Pant as deep as you can.
• Chew and then swallow a piece of dry bread.
• Breathe ten times into a paper bag, sealing in the air you breathed out by holding the bag’s edges tight against your face.

A few alternative and homeopathic remedies exist for hiccups.

The following remedies lead to vagal stimulation (only one should be used at any given time):

• Iced gastric lavage
• Valsalva maneuver
• Carotid sinus massage (performed only by experienced personnel after exclusion of contraindications)
• Digital ocular globe pressure (performed only by experienced personnel after exclusion of contraindications)
• Digital rectal massage

Various techniques are used that interfere with normal respiratory function, such as the following:

• Breath holding
• Hyperventilation
• Gasping (as in fright)
• Breathing into a paper bag (which increases arterial carbon dioxide tension [PaCO 2])
• Pulling the knees up to the chest and leaning forward
• Using continuous positive airway pressure
• Rebreathing 5% carbon dioxide

Mental distraction sometimes works:

• Behavioral conditioning (including other members of the family unit)
• Hypnosis
• Acupuncture (including near-infrared irradiation of acupoints)
• Phrenic nerve or diaphragmatic pacing – Incidental cure of hiccups during cardioversion has been reported
• Prayer

There are several risks and complications associated with hiccups.

Interference with ventilation

Severe hiccups can interfere with ventilation in anaesthetised and ventilated patients. This is often seen with the use of a laryngeal mask airway. Hiccups in intubated infants can lead to hyperventilation and subsequent respiratory alkalosis.

Interference with medical procedures

Severe forms of hiccups during surgery, endoscopy, or imaging can jeopardise the quality of the procedure.

In the rare situation where hiccups cause a sudden interference with a medical procedure or imaging study (endoscopy, surgery, CT scan, MRI), the patient can be anaesthetised with either a volatile or non-volatile anaesthetic to achieve deeper sedation. If this is unsuccessful, neuromuscular blocking agents (e.g., vecuronium) and mechanical ventilation can be used to arrest the symptom. After the effects of the neuromuscular blocker wear off, the hiccups often return, and it should be noted that anaesthesia and securing the airway (e.g., with a laryngeal mask airway) may not be beneficial and may even cause a worsening of symptoms.

Wound dehiscence

Hiccups in the postoperative period do not only cause discomfort but can also lead to wound dehiscence and insufficiency at the site of an anastomosis.

Weight loss

Severe forms of persistent intractable hiccups can complicate eating and drinking. This may lead to malnutrition and dehydration, with subsequent loss of weight. Weight loss is not uncommon in patients with persistent intractable hiccups.

Oesophagitis

Hiccups can result in reflux, leading to oesophagitis. Persistent reflux worsens the symptoms of oesophagitis, which is itself a cause of persistent intractable hiccups. Thus, a vicious cycle is created that must be interrupted.

Cardiac arrhythmias

Supraventricular and ventricular arrhythmias can result from severe diaphragmatic contractions. It should be noted that some underlying conditions can lead to both cardiac arrhythmias and hiccups.

Insomnia

Hiccups may keep the individual from sleeping, leading to fatigue and exhaustion during the day. Alertness and concentration are impaired, with consequences for work and social activities. Constant stimulation of the sympatho-adrenergic system may lead to adverse effects on the cardiovascular system.