The recurrent nerve (vagus), located in the larynx, is responsible for the functioning of the vocal apparatus. Some of its fibers go to the heart. When the recurrent nerve is damaged, speech abilities are impaired; in severe cases, breathing difficulties may occur, which is explained by a decrease in muscle activity in the larynx. Treatment of the pathology is selected based on the complexity of the case.
Where is the laryngeal nerve located and causes of damage?
As a continuation of the cranial fibers, the superior laryngeal nerve is divided into two parts and runs on both sides of the neck. It is noteworthy that first it reaches the chest, forming a kind of loop there, and then returns to the larynx. The inferior laryngeal nerve runs transversely towards the shoulder blades, clavicle and mammary glands and then clasps several large arteries, including the carotid.
The branches that make up the upper section innervate the larynx, and the nerves that enter the lower section innervate the tissues of the lining of the esophagus, trachea and heart. Therefore, when these fibers are paralyzed, the symptoms vary.
The laryngeal nerve contains sensory and motor fibers. Because of its division, unilateral and bilateral paralysis is divided into several branches, which also differ in symptoms and require their own approaches to treatment.
Damage to the part of the central nervous system responsible for the innervation of the larynx leads to:
- diseases of the central nervous system affecting the nerves that run from the brain;
- surgery for thyroid diseases;
- pathologies of the thyroid gland, causing proliferation of the organ;
- errors during the administration of endotracheal anesthesia;
- neck injuries;
- metastases in the neck (lymph nodes);
- operations on the pharynx or esophagus;
- cancer of the esophagus;
- aortic aneurysm;
- malignant tumor in the lung;
- pulmonary tuberculosis.
The most common cause of pathology is damage to the recurrent nerve during removal of the thyroid gland.
In some cases, acute intoxication of the body or infectious infection leads to paralysis. Sometimes the cause of the pathology cannot be determined. In such situations, the patient’s vocal functions are usually restored without outside intervention within 2-3 months.
Location of the larynx
Before moving on to considering the blood vessels and innervation of the larynx, you should understand where it is generally located, as well as what cartilage and muscles form it.
This is really important, since blood vessels and nerves are needed specifically to nourish these muscles and cartilage. The larynx can be well palpated, since it is located superficially, almost immediately under the skin. And some protrusions are visible to the naked eye. They serve as anatomical landmarks when performing tracheostomy. In men, the Adam's apple is clearly visible, which is actually a protrusion of the thyroid cartilage. In girls and children, you can see the arch of the cricoid cartilage.
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The upper border of the larynx is the opening, which is called the entrance to the larynx. From below, the larynx smoothly passes into the trachea - the breathing tube. On the sides of it are the lobes of the thyroid gland, as well as the vessels and nerves of the neck.
Symptoms
When the laryngeal nerve is damaged or inflamed, symptoms are often determined by the location of the pathological process. The nature of the clinical picture may change slightly with unilateral and bilateral paralysis. The following general symptoms of damage to the recurrent nerve are distinguished:
- hoarseness and change in voice timbre (the intensity of the symptom gradually increases);
- difficulty breathing when swallowing food (dysphagia);
- noisy, wheezing breathing;
- loss of voice;
- attack of suffocation (typical for bilateral lesions);
- causeless shortness of breath;
- decreased tongue mobility and palate sensitivity;
- a feeling of numbness in the tissues of the epiglottis;
- frequent entry of food into the larynx;
- high blood pressure;
- active heartbeat;
- dry cough, accompanied by the throwing of gastric juice into the mouth;
- breathing disorders of various types.
In case of partial damage to the nerve fiber of the larynx, recovery lasts several weeks (up to six months). During this period, speech and other functions are normalized without outside intervention.
With bilateral damage, the skin becomes pale and the extremities become cold. A few hours after the onset of these symptoms, breathing returns to normal. However, if a person begins to move, these phenomena return. Therefore, for bilateral neuropathy, a tracheotomy is indicated, which involves artificial expansion of the airways.
Etiology
It is often not possible to establish the true root cause of glossopharyngeal neuralgia. In this case, we have to talk about idiopathic etiology and put forward the most likely versions.
As for secondary causes, the structure of the glossopharyngeal nerve is damaged as a result of such factors:
- compression of the nerve root by the hypertrophied styloid process;
- compression by the cerebellar artery at the exit from the cranial cavity;
- pathological ossification (ossification) of the stylohyoid ligament;
- strangulation by an abnormally tortuous vein or artery;
- thrombosis of the sigmoid sinus;
- basilar artery aneurysm;
- nerve paresis due to arachnoiditis of the posterior cranial fossa;
- abscess or carcinoma in the parapharyngeal area;
- vascular malformation - an abnormal connection of veins in the posterior cranial fossa;
- neoplasm in the area of the cerebellopontine triangle;
- pharyngeal carcinoma and nasopharyngeal carcinoma;
- postoperative iatrogeny against the background of medical unprofessionalism.
Such pathologies occur as a result of oncology, fractures of the base of the skull, after severe infections, intoxications or against the background of meningitis. Atherosclerotic changes and certain metabolic disorders can also negatively affect the condition of nerve fibers.
Diagnostic methods
Recurrent neuropathy is diagnosed based on the results of collecting information about the patient's condition. In addition to the medical history, pathologies help in determining the disease:
- external examination of the larynx;
- CT;
- X-ray in various projections;
- phonetography;
- laryngoscopy;
- electromyography of the laryngeal muscles.
In order to identify the causative factor, ultrasound, CT and other methods of examining the thyroid gland, brain, heart, lungs, and respiratory system are used. Additionally, a biochemical blood test is prescribed to identify the pathogenic agent.
In the case of bilateral laryngeal paralysis, a tracheotomy is first performed, and then the patient is examined. This is explained by the fact that paralysis of this type poses a direct threat to the patient’s life.
Blood vessels
The blood supply to the larynx is quite abundant. It receives blood from the laryngeal arteries: superior and inferior. The superior laryngeal artery, in turn, branches off from the superior thyroid artery. This occurs slightly above the edge of the thyroid cartilage. In the sublingual-thyroid septum there is an opening through which this artery penetrates the wall of the larynx.
On the opposite side there is the same superior laryngeal artery. They anostomose, that is, connect, with each other, giving another branch to the internal part of the larynx. The middle laryngeal vessel also departs from the superior thyroid artery.
The inferior laryngeal artery branches, respectively, from the inferior thyroid vessel. The latter, in turn, arises from the subclavian artery. In the larynx, the inferior vessel passes behind the joint between the thyroid and cricoid cartilages, supplying blood to the posterior surface of the larynx. This artery forms anastomoses with the upper and middle vessels.
Thus, through the arteries, oxygenated blood flows to the cartilage and muscles of the larynx. Oxygen-poor blood leaves the laryngeal structures through the veins of the same name. It collects in the venous plexuses, which then pass into the superior and inferior laryngeal veins. They, in turn, flow into the superior and inferior thyroid veins. The superior vessel further carries blood to the internal jugular vein. The inferior vessel is a tributary of the brachiocephalic vein.
Drug treatment
Treatment of paresis of the recurrent laryngeal nerve is often carried out with the help of medications:
- B vitamins;
- neuroprotectors;
- antibiotics;
- hormonal medications;
- antibacterial agents.
The type of drugs is selected taking into account the characteristics and causes of the disease. If paresis is caused by pathologies of the thyroid gland, taking synthetic thyroid hormones is recommended. In cases where an extensive hematoma forms in the larynx area, it is recommended to take medications to resolve the bruise.
Muscles of the larynx
Separate attention should be paid to the muscles of the larynx. They are divided into two types: intrinsic and skeletal. The muscles of the first type are attached to the cartilage of the larynx from the outside at one end, and the other is attached to the bones of the skeleton (sternum, collarbone, lower jaw, scapula, etc.). These muscles include:
- thyrohyoid;
- sternothyroid;
- sternohyoid;
- digastric;
- scapular-hyoid;
- awl-hyoid.
Intrinsic muscles are divided into internal and external. Moreover, there are only two external muscles - the paired cricothyroid.
Internal muscles are divided into several groups depending on their functional characteristics:
- muscles that regulate the width of the entrance to the larynx;
- muscles that control and change the condition of the vocal cords;
- epiglottis muscles.
Other treatments
For mild forms of damage to the recurrent nerve, reflexology is used, which involves treatment by applying pressure to certain points in the larynx area. This method stimulates the restoration of damaged tissue. Treatment also includes special exercises, the effect of which is aimed at normalizing vocal functions. Such classes are conducted by a phoniatrist.
For bilateral recurrent nerve palsy, laryngoplasty is recommended. The method is not used for malignant tumors and some other pathologies, as well as for elderly patients.
During surgery, access to the problem area is made through the mucous membrane of the mouth or neck and collagen or Teflon is introduced, which increases the volume of nerve fibers.
If necessary, a surgical method is used that involves excision of some tissues in the larynx area, after which individual fibers are transferred to a new area. This approach is used for severe asphyxia, when the airways are completely blocked.
The prognosis after surgery for recurrent nerve paresis is determined on an individual basis. In uncomplicated cases, it is possible to partially or completely restore both respiratory and vocal functions.
Recurrent nerve palsy is a dangerous condition that interferes with the motor activity of the muscles in the throat area. Such violations can cause suffocation, leading to the death of the patient.
The essence of the disease
Neuralgia of the glossopharyngeal nerve is a certain type of damage to the paired nerve on one side .
The nerve consists of 4 nuclei localized in the medulla oblongata and a group of fibers. The bundles of parasympathetic fibers are responsible for salivation, thanks to the motor ones, the pharynx rises, and the sensory fibers provide the taste sensations of the epiglottis and the back of the tongue.
Extensive damage can involve the laryngeal and hypoglossal branches of the nerve. The pathology is also known as Sicard syndrome and is located under ICD 10 code G52.1.
Neuralgia occurs both as an isolated disease and as a complication of a particular pathology.
