Nerves connect all parts of the body to and from brain in order to improve immunological, physiological and hormonal functions of the body. Nervous system is highly intricate and each and every nerve supply important sensory and motor information to the relay stations in the brain (neurons) to perform critical activities. Vagus nerve is one of the most important nerves in the body with a number of functions. However, vagus nerve disorders or vagus damage can occur, causing uncomfortable symptoms.
What is Vagus Nerve?
Vagus nerve is one of the most important cranial nerve that is labeled as 10th nerve (out of 12 cranial nerves) that exits from the intervertebral foramina of 10th cervical vertebrae. Vagus nerve is popularly known as wandering nerve since it originates at the level of medulla of brain and transverse upper thoracic and abdominal region to supply various organs and systems (like respiratory, circulatory and digestive systems).
Vagus Nerve Disorders
Certain health condition and disorders affect the functioning of nerves by causing damage to nerve fibers via inflammatory, infectious or neoplastic processes leading to abnormal activity of vagus nerve.
Symptoms of Vagus Nerve Disorders
Symptoms of vagus nerve disorders are classified as overactive (in which symptoms are produced due to excessive release of neurotransmitters) and inactive or under-active (in which less stimulation of nerve interferes with the systemic functioning of organs). Classic symptoms of vagus nerve disorders include:
Pain is the most common symptom of vagus nerve disorders as a result of mechanical pressure, trauma or injury that leads to inflammatory swelling leading to neuralgia. Vagus nerve can be damaged throughout its course but most common nerve pain symptoms are due to pinched nerve (when nerve exits through tiny foramina in the skull).
2. Organ Dysfunction
In some conditions, a branch or tributary of nerve is affected that leads to localized symptoms of organ dysfunction due to damage to nerve fibers or discrepancy in the synthesis of neurotransmitters. Classically the involvement of system/ organ is dependent upon the site of injury of vagus nerve.
3. Muscle Cramps
Vagus nerve supply muscles of vocal cord and any defect or disorder of vagus nerve directly interfere with voice and breathing. Moreover, it may also involves other muscles that are supplied by vagus nerve.
4. Difficulty in Swallowing
Glottis is normally closed when a person is swallowing in order to prevent the aspiration of food. This is managed by gag - reflex (gagging sensation if the back of throat is touched). In patients of head injury or stroke, gag reflex may get impaired leading to choking while eating and difficulty in swallowing.
5. Peptic Ulcer
Defects in the normal functioning of Vagus nerve may impair the normal control mechanisms that modulate the gastric acid secretion. Excessive secretion of peptic acid can lead to ulceration, dyspepsia and gastro-esophageal reflux disease.
The under-activity of vagus nerve may interfere with the blood supply of stomach after ingestion of food that leads to improper digestion. Gastroparesis is marked by painful spasms in the stomach that affect normal food intake, heartburn, nausea and weight loss.
Over-activity of Vagus nerve increases the firing rate of receptors that presents with sudden episodes of collapse and fainting (also referred to as vasovagal reflex). Although, it is not dangerous, but fainting episodes may increase the risk of accidental injuries that may prove life threatening.
8. Other Symptoms
Other symptoms include changes in the rhythm of heart, urinary difficulties and changes in vocal tone.
Treatments of Vagus Nerve Disorders
In most cases, lifestyle modification and certain exercises can minimize the intensity of symptoms; however, surgical intervention may be needed in some cases.
1. Vagus Nerve Stimulation
Vagal nerve stimulation can be achieved by a device (similar in activity to cardiac pacemaker) that is implanted beneath the skin and helps in generating impulses that can help in managing symptoms of depression and seizures.
2. Neck Extension Exercises
Often times, pressure in the tendons or tense muscles can press upon vagus nerve that may lead to hyper or hypoactivity of nerves. 3- Dimensional exercises like neck extension (moving your chin away from chest as far as possible), neck flexion (touching your chin with your chest) and neck retraction exercises can help in decreasing pressure on nerve.
Other exercises can directly involve throat, floor of the mouth and base of the skull to improve vocalization, swallowing and breathing
Yoga exercises are helpful in the moderate stimulation of vagus nerve that helps in improving the systemic functions of vagus nerve. Moreover, different postures that are adopted during yoga exercise helps in releasing pressure from the delicate nerve fibers.
4. For Gastroparesis
In order to manage symptoms of Gastroparesis and reduce the risk of severe malnutrition, healthcare providers suggest the use of feeding tube that supply the nutrients directly to intestines without crossing stomach. In order to reduce the symptoms of nausea and vomiting, medications like ondansetron can be employed. Metoclopramide is usually reserved for severe cases (due to possible risk of stimulation of stomach).
5. For Fainting
Different medications are employed to manage the fainting episodes (that mostly involve controlling vasovagal discharge). Sertraline or paroxetine are currently the treatment of choice for such cases.
Vagus Nerve Damage
Nerves are protected by myelin sheaths that serve to prevent the delicate nerve fibers from damage and destruction; however, aberrations in normal biochemical environment due to excessive alcoholism or persistently raised blood sugar levels can lead to swelling of myelin sheaths that lead to permanent destruction of nerve fibers leading to inactivity of nerves. Other causes includes inflammatory disorders, autoimmune destruction of nerves (in the setting of diseases like amyotrophic lateral sclerosis, multiple sclerosis and other), viral infections and damage due to neoplastic conditions that press upon nerves causing mechanical damage.
Symptoms of vagus nerve damage may range from permanent changes in the voice to defect in cardiac rhythm and breathing difficulties. Damage to superior laryngeal branch may lead to impaired gag reflex and choking.
In case of suspected damage to vagus nerve, seek the help of a registered healthcare provider at your earliest convenience to limit the area of damage and to prevent life threatening complications.