Deglutition Syncope - Causes, Types, Diagnosis and Management

Introduction:

Deglutition syncope is a rare neurally mediated reflex syncope that occurs during swallowing. It is also known as swallow syncope. The clinicians can identify individuals with swallow syncope with careful evaluation of the condition. In addition, clinicians should be aware as patients with swallow syncope can report across multiple disciplines.

What Is Deglutition?

Deglutition is the transportation of food or liquid from the mouth to the stomach. The contraction and relaxation of oral and pharyngeal muscles are required for normal deglutition. The structures commonly involved in deglutition are the tongue, hard palate, soft palate, pharyngeal muscles, esophagus, and gastroesophageal junction. In addition, the nerves responsible for coordinating the swallowing activity are trigeminal, facial, glossopharyngeal, vagus, and hypoglossal nerves. The three phases of deglutition or swallowing are oropharyngeal, esophageal, and gastroesophageal.

What Is Syncope?

Syncope is the temporary loss of consciousness due to a drop in blood flow to the brain. It can happen due to a sudden fall in blood pressure, heart rate, or changes in the blood flow to other body areas. If this phase is passed out, the individual becomes conscious and alert.

What Are the Types of Syncope?

The type of syncope depends on what causes the problem. The different types of syncope are:

• Vasovagal syncope.

• Postural syncope.

• Neurologic syncope.

• Postural orthostatic tachycardia syndrome.

What Are the Symptoms of Syncope?

The most common symptoms of syncope are:

• Blacking out.

• Falling for no reason.

• Feeling lightheaded.

• Feeling dizzy.

• Feeling drowsy.

• Fainting after eating or exercising.

• Feeling weak.

• Vision changes.

• Headaches.

What Are the Triggering Factors of Deglutition Syncope?

Deglutition syncope does not occur every time individual swallows. There may be some triggers causing it to occur. Syncope can occur on swallowing solids, liquids, or both solids and liquids. They can present especially in conditions where the individual swallows a large chunk and has not chewed properly. In addition, the eating habits, temperature, and stickiness of foods are associated with triggering factors. Finally, the type of liquid also triggers syncope. For example, carbonated beverages.

How Does Deglutition Syncope Occur?

The most common mechanism behind swallow syncope is increased vagal reflex activation during swallowing, inhibiting cardiac activities. During deglutition, impulses are transmitted from the esophageal plexus through the vagus nerve to the medulla oblongata. Simultaneously, involuntary peristalsis occurs due to the esophageal branch of the vagus nerve. The presence of reflex arcs between the afferent and efferent fibers results in vagal stimulation leading to bradycardia (decreased heart rate) and hypotension (reduced blood pressure).

The mechanoreceptors on the esophagus are found to be the primary cause of deglutition syncope in individuals with disorders of the gastrointestinal system.

What Are the Techniques Used to Detect Deglutition Syncope?

• Provocative Testing: The heart functions are monitored simultaneously by introducing the triggering factors to the individual.

• Tilt Table Testing: The individual is laid flat on a motorized table for five minutes, suddenly moved to a vertical position, and allowed to stay for 5 to 45 minutes. The cardiac functions are monitored simultaneously. If the individual shows any symptoms of syncope, the diagnosis can conclude.

• Holter Monitoring: A Holter monitor is a device that records the heart’s rhythm. The individual can wear it for one to two days, and the rhythmic change can be monitored during different activities. The individual is advised to note down the activities and time during which it is done during the entire day. This would help the healthcare professional to identify the triggering factor for unusual changes in the cardiac rhythm.

• Implantable Loop Recorder: It is a cardiac monitoring device that can be implanted in an individual’s chest region through a small incision. This helps the doctor to monitor your cardiac activities remotely. The loop recorder can be placed in position for about three years. It is recommended when the individual has unexplained fainting episodes, stroke, and arrhythmias.

How Is Deglutition Syncope Managed?

• The initial step in managing any disease is identifying the underlying cause. The same applies to deglutition syncope. The cause may be gastrointestinal, neurological, cardiovascular, and conduction abnormalities.

• If the condition is due to triggering factors, it should be identified and avoided.

• The technique of swallowing should be modified. The individual is advised to swallow small amounts of food and chew the food properly before swallowing.

• If there are any chances of vasovagal syncope, the individual should take more fluid and salt.

• The chances of injuries during the syncope attack are minimal. However, they have to be assessed and treated.

• Since the triggering factors causing swallowing syncope are already known, the diagnosis can be determined by provocative testing with various solid and liquid food items and monitoring the echocardiograph to confirm the diagnosis.

• If cardioinhibitory action is identified while monitoring, certain conservative strategies should be considered before pacemaker implantation.

• Symptomatic management with pharmacotherapy is recommended. Case reports have shown atropine before meal intake to be effective in these cases.

• Cardio Neuroablation (a technique where the cardiac branch of vagal reflex is eliminated by radiofrequency to treat neurocardiogenic syncope without surgery) is considered if there are recurrent symptoms and if the individual is young and strong, preferably to avoid a pacemaker.

Can a Pacemaker Cure Deglutition Syncope?

Syncope occurring during swallowing may be unpredictable. But if it is so serious, causing recurrent problems, and the heart tends to slow during swallowing, a pacemaker would help. However, advice from a specialist is necessary.

Is Deglutition Syncope Life-Threatening?

Deglutition or swallow syncope is an unpredictable and unusual type associated with life-threatening symptoms such as hypotension and bradyarrhythmia. It is also one of the conditions with delayed diagnosis and management.

Conclusion:

Deglutition syncope is an unusual condition that can significantly affect the individual's quality of life. It is dangerous if encountered during strenuous activity, driving, or operating heavy machines, which can lead to serious injuries to the individual. However, the condition is treatable, but it may take some time until its diagnosis is confirmed.