Overview of laryngeal paralysis
Laryngeal paralysis refers to the laryngeal muscle dysfunction caused by vagus nerve or recurrent laryngeal nerve or superior laryngeal nerve injury hoarseness, choking, aspiration, dyspnea, swallowing disorders mainly due to central and peripheral injuries based on a clear cause of the cause of the injury, the treatment of the cause, take medication, speech correction, surgery and other methods.
Definition
Laryngeal paralysis is a motor disorder of the vocal cords caused by damage to the motor nerve conduction pathways that innervate the muscles of the larynx, which may be accompanied by sensory disorders of the larynx.
It is often referred to as vocal fold paralysis because it is characterized by dysfunction in the inward and outward movement of the vocal folds.
Motor disorders of the vocal folds may be accompanied by sensory disorders of the larynx.
Classification
Classification according to the cause
Trauma, tumor, inflammation are the common causes, but there are also a small number of congenital and idiopathic vocal cord paralysis.
Classification according to the side of the injury
Unilateral vocal cord paralysis and bilateral vocal cord paralysis.
Classification according to the involved nerves
Vocal cord paralysis caused by injury to the recurrent laryngeal nerve alone.
Cricoarytenoid motor dysfunction, or dysfunction of vocal cord tone regulation and sensation caused by supraglottic laryngeal nerve injury alone.
Mixed vocal cord paralysis with supraglottic laryngeal nerve injury.
Combined vagus nerve injury with posterior cerebral nerve injury.
Classification according to the degree of injury
Complete vocal cord paralysis, incomplete vocal cord paralysis. According to the anatomical structure of the injury, from mild to severe, it is categorized as axonal injury, intraneural injury, and nerve dissection.
Morbidity
Incidence: laryngeal paralysis is a common disease, one of the main diseases of laryngology, the incidence rate of 1.04/100,000~9.90/100,000 is reported abroad, and there is no epidemiological data in China.
Etiology
Causes
The etiology is complex, and any damage to the laryngeal motor nerve and sensory nerve conduction pathway may lead to its occurrence. The causes are mainly divided into central and peripheral injuries.
Central injury
Cerebral artery thrombosis, brain tumor, medullary cavernous disease, poliomyelitis, rheumatoid encephalitis, multiple cerebrospinal sclerosis, atrophic rigidity, hereditary motor disorders, cerebral hemorrhage, epilepsy, tremor paralysis, choreoathetosis, and cerebral softening, etc., which can be the cause of laryngeal paralysis.
Peripheral injury
Lesions below the nucleus of the vagus nerve can result, especially below the jugular foramen, lesions involving the vagus nerve above the branching out of the recurrent laryngeal nerve, and lesions involving the recurrent laryngeal nerve and the superior laryngeal nerve.
Trauma
Skull base fracture, neck trauma, medical trauma (e.g. thyroid surgery, thoracic mediastinal surgery, lateral skull base neck surgery, etc.).
Tumor
Nasopharyngeal carcinoma, thyroid tumor, metastatic carcinoma in the neck, carotid body tumor, etc. can cause laryngeal paralysis by compressing or infringing the vagus nerve and the laryngeal reentrant nerve.
Aortic aneurysm, lung cancer, esophageal cancer, etc. invade and compress the laryngeal return nerve of thoracic segment.
Inflammation
Infectious diseases such as diphtheria, influenza, rheumatism, measles, syphilis, etc. may lead to peripheral neuritis of the recurrent laryngeal nerve.
Idiopathic
Unexplained demyelinating lesions of the nerve may also lead to idiopathic laryngeal palsy.
Congenital
Vocal cord paralysis that occurs immediately after birth; birth injury needs to be ruled out.
Other
Radiation therapy-induced nerve damage, lead, arsenic, ethanol poisoning, etc. can also cause laryngeal paralysis.
Pathogenesis
The left recurrent laryngeal nerve bypasses the arch of the aorta, which is a longer distance from the subclavian artery to the laryngeal muscle than the right side, and its location is more superficial, making it more susceptible to injury.
Injury to the nerve is severe, or severed, or light damage to the axon of the nerve fiber, so that the conduction of electrical impulses of the nerve is blocked, resulting in the innervation of the vocal cord movement disorder, sensory nerve damage caused by the impaired swallowing and coughing reflexes, coupled with impaired movement, resulting in aspiration, choking cough.
Symptoms
Main Symptoms
Hoarseness
Vocal cord dyskinesia leads to hoarseness, unilateral hoarseness, easy fatigue, and a sense of air leakage when speaking and coughing. When both sides are completely paralyzed, the voice is hoarse and weak, monotonous, and the speech is laborious, as if it were a whisper, and cannot last long.
Choking and aspiration
The vocal folds lose their normal protective reflexes and cannot be closed, causing choking; secretions are often accumulated in the trachea and there is difficulty in expectorating; there is a wheezing sound when breathing.
Difficulty in swallowing
The sensation of the laryngeal mucosa decreases or disappears, and the movement disorder of the muscles in the larynx leads to dysphagia.
Dyspnea
Incomplete paralysis of the double laryngeal recurrent nerve leads to the gradual fixation of the vocal cords in the median position, and the dyspnea gradually worsens.
Other symptoms
Laryngeal recurrent nerve injury is accompanied by injury to the posterior cerebral nerves (glossopharyngeal nerve, hypoglossal nerve, parasympathetic nerve), and the clinical manifestations may be accompanied by symptoms of posterior cerebral nerve paralysis, such as weakness of palate lifting, deviation of the uvula, deviation of the tongue extensor, and atrophy of the sternocleidomastoid muscle and the trapezius muscle, in addition to the symptoms of laryngeal recurrent nerve palsy.
Complications
Aspiration pneumonia
With paralysis of the supraglottic laryngeal nerve on both sides, due to the complete loss of laryngeal mucosal sensation, aspiration pneumonia may occur when food, drink and saliva are accidentally choked into the lower respiratory tract.
It manifests as spasmodic cough, shortness of breath and wheezing.
Acute laryngeal obstruction
Incomplete paralysis of bilateral recurrent laryngeal nerves can cause laryngeal obstruction because both vocal cords can not be adducted, which can cause asphyxiation in severe cases if not treated in time.
Laryngeal obstruction
Mixed laryngeal nerve palsy refers to total paralysis of the superior laryngeal nerve and the recurrent laryngeal nerve. People with bilateral paralysis can not form the ventricular cord, vocal function is completely lost, can only excuse, pharyngeal and palatal resonance cavity to form speech.
Medical treatment
Department of Medicine
Otorhinolaryngology
If you experience hoarseness, dyspnea, dysphagia, choking and coughing, it is recommended that you consult a doctor promptly.
Emergency Department
If you have difficulty breathing, we recommend that you seek immediate medical attention.
Preparation
Information on how to get to the doctor: registration, preparation of documents, and common problems.
Tips for seeking medical treatment
Before consultation, take rest and avoid strenuous exercise.
Adjust your mood and stabilize your mind.
Eat a light diet and stop smoking and drinking.
Keep an empty stomach.
Preparation List
Symptom list
Especially need to pay attention to the time of onset of symptoms, special manifestations, etc.
Is there frequent hoarseness, breathlessness, choking, difficulty in swallowing?
Does dyspnea occur?
Medical history checklist
Is there a history of trauma or surgery to the larynx?
Is there a history of head and neck trauma, intracranial hemorrhage, thrombosis, or cranial tumor?
Is there a history of head and neck tumors?
Is there a history of specific infectious diseases such as diphtheria, syphilis, leprosy, etc.?
Checklist
Test results in the last six months, which can be brought to the doctor’s office
Examples include routine blood tests, neck imaging, nasopharyngoscopy and laryngoscopy.
Medication list
Medication used in the last 3 months, you may bring it to the doctor if there is a box or package of the medication
Glucocorticosteroids: dexamethasone, prednisone, etc.
Antiviral drugs: oseltamivir, ribavirin, etc.
Nutritional drugs: methylcobalamin, vitamins, etc.
Diagnosis
Diagnosis is based on
Medical history
History of trauma or surgery to the larynx.
History of head and neck trauma, intracranial hemorrhage, thrombosis, and cranial tumors.
History of head and neck tumor.
History of diphtheria, syphilis, leprosy and other special infectious diseases.
Clinical manifestations
Symptoms
Patients present with hoarseness, choking, aspiration, dysphagia, dyspnea, aspiration pneumonia, acute laryngeal obstruction.
Physical signs
The main manifestations of the patient’s vocal folds are dyskinesia, dysfunction or fixation of abduction and adduction, relaxation of the vocal folds, deviation of the vocal fissure, up and down movement of the vocal folds of the affected side in response to airflow during respiration, and relaxation of the cricoarytenoid muscles.
Combined nerve palsy is accompanied by posterior cerebral nerve palsy manifestations such as weakness of soft palate lifting, deviation of uvula, deviation of tongue extension, atrophy of sternocleidomastoid and trapezius muscles.
Laboratory Tests
Blood test
Blood routine mainly detects whether infection, anemia, and helps to determine the etiology.
Rheumatologic and immunologic examination
For unexplained vocal cord dyskinesia, if arthritis is suspected to be the cause, rheumatoid factor and anti-streptococcal hemolysin O test should be detected; relevant immunological indexes should be detected to exclude immune diseases.
Others
Detection of tumor markers such as EBV to assist in ruling out head and neck or chest tumors such as nasopharyngeal carcinoma.
Detection of trace elements such as lead, arsenic, etc., to help diagnose or exclude caused by poisoning.
Laryngoscopy
Laryngoscopy is a necessary test for patients with vocal cord paralysis.
Laryngoscopy helps to determine the type of vocal cord paralysis, the nature of the injury, the extent and duration of the disease.
Dynamic laryngoscopy
Dynamic laryngoscopy shows that the mucosal waves of the vocal folds are weakened and lost on both the healthy and affected sides, with the affected side being the most severe. Vocal cord vibration is irregular and asymmetric, the vibration amplitude is weakened, a few abnormal enlargement, and the closing phase of the vocal folds is shortened or even disappeared.
Imaging examination
Craniocerebral high-resolution CT, magnetic resonance examination
Indications: Enhanced MR or CT may be done in cases where the cause of vocal cord paralysis is unknown, especially in the presence of other posterior group cerebral nerve damage.
Purpose: To exclude tumors and other lesions on the vagus and recurrent laryngeal nerve pathways that travel from the base of the skull to the plane of the aortic arch.
Ultrasonography
Ultrasound of the thyroid gland, etc., to exclude or identify vocal cord paralysis caused by thyroid tumors.
Pharyngography
Also known as TV X-ray fluoroscopy of swallowing function, it is a clinical examination method that utilizes imaging to observe dysphagia, and is considered to be the “gold standard” for evaluating dysphagia.
It is suitable for patients with vocal cord paralysis who have difficulty in swallowing, and helps to evaluate swallowing function and the risk of aspiration.
CT scan of the cricoarytenoid joint
Helps to see if the vocal cord paralysis is caused by dislocation of the arytenoid cartilage.
Subjective and objective voice assessment
Subjective Assessment
Voice assessment is used to evaluate the degree of voice impairment in patients with vocal fold paralysis, to help in differential diagnosis and to analyze the effect of treatment, including auditory perception assessment and patient self-assessment.
Auditory perception assessment can be done by GRBAS, RBH, etc. Patient self-assessment is often done by using the Chinese version of Voice Disorder Index.
The subjective assessment indexes of vocal cord paralysis patients all showed different degrees of increase.
Acoustic analysis
The most commonly used acoustic analysis indexes were fundamental frequency (F0), fundamental frequency perturbation (jitter), amplitude perturbation (shimmer), and noise-to-harmonic ratio (NHR), etc. The F0 of patients with unilateral vocal fold paralysis could be higher or lower than normal, and the jitter, shimmer, and NHR were all higher than normal.
Laryngeal aerodynamic assessment
The most commonly used assessment index is the maximum phonation time (MPT), which is used to assess the severity of vocal fold closure insufficiency.
The MPT is 15-20 seconds in healthy adults, and the longest vocalization time is significantly reduced in patients with vocal fold paralysis.
A decrease in the MPT indicates an increase in the degree of vocal fold closure insufficiency, a decrease in voice quality, and an increase in vocal fatigue.
Fiberoptic endoscopic swallowing function test
Changes in pharyngeal structures during swallowing, the morphology of the pyriform fossa and the presence of effusion can be observed. High vagal nerve injury or combined vocal cord paralysis is often associated with shallow pyriform fossa and effusion.
Laryngeal nerve electrophysiologic examination
Laryngeal nerve electrophysiologic examination includes laryngeal electromyography and laryngeal evoked muscle potential examination, which is the only method to detect the electrical activity of laryngeal nerves and muscles at present.
It can qualitatively and quantitatively diagnose the degree of neuromuscular damage and is the gold standard for diagnosing vocal cord paralysis.
Diagnostic criteria
The main basis for diagnosis is medical history, clinical symptoms, physical examination, laryngoscopy.
Imaging and laboratory tests are favorable for diagnosis and differential diagnosis.
Dynamic laryngoscopy, voice function assessment, swallowing function assessment, aerodynamic assessment are used to determine the effect of vocal cord paralysis on laryngeal function.
Differential diagnosis
Arytenoid cartilage dislocation
Similarities: Hoarseness and choking are seen.
Differences: arytenoid cartilage dislocation is often associated with a history of general anesthesia for tracheal intubation or a history of neck trauma. Laryngoscopy, stroboscopy, and thin-layer CT of the larynx can help to differentiate.
Cricoarytenoid joint injury
Similarities: both present with hoarseness, choking, vocal fold immobilization
Differences: Cricoarytenoid joint injuries are mostly secondary to laryngeal trauma resulting in damage to the cricoarytenoid joint. Stroboscopic laryngoscopy, laryngeal electromyography, arytenoid cartilage toggle test, and surgical exploration can help to differentiate.
Myasthenia gravis
Similarities: both present with hoarseness, weak phonation, swallowing disorders, etc.
Differences: Myasthenia gravis is the most common neuromuscular junction disease. Symptoms in these patients are typically characterized by mild symptoms in the morning and severe symptoms in the evening, which are relieved by rest. Laryngoscopy and laryngeal electromyography can help to differentiate.
Treatment
Treatment principle: On the basis of clarifying the cause of the disease, treat the cause to improve or restore voice function, relieve dyspnea and dysphagia, and prevent complications.
Etiologic treatment
On the premise of defining the cause of laryngeal paralysis, give appropriate treatment measures and actively relieve the cause.
Including anti-inflammatory and decongestive, tumor resection and decompression surgery, trauma hematoma removal and so on.
Drug treatment
Neurotrophic drugs such as methylcobalamin and vitamin B1 should be given systemically or locally.
Early glucocorticoid anti-inflammatory drugs, commonly used drugs are prednisone, methylprednisone, dexamethasone and so on.
Improvement of microcirculation drugs such as nimodipine, etc., energy synergists such as adenosine triphosphate.
Voice Rehabilitation Therapy
Suitable for people
For patients with dysphonia caused by central lesions, voice quality can be improved to a certain extent through certain speech correction.
It is also effective for some peripheral unilateral laryngeal paralysis. Even for patients who eventually need to undergo surgical intervention, speech therapy is an effective means in the waiting stage, which is conducive to the patient’s recovery.
Training methods
Relaxation training: the purpose is to reduce the muscle tension and eliminate the state of tension, reduce the excessive tension and spasm of the muscles during articulation. It includes whole body relaxation training, local relaxation training (neck relaxation training, laryngeal relaxation training) and so on.
Breathing training: the purpose is to establish correct abdominal breathing, eliminate abnormal breathing patterns, strengthen the abdominal muscles and diaphragm, reduce the tension of the laryngeal muscles, coordinate the breathing and articulation, and guarantee the support of the airflow for articulation.
Phonation training: The purpose is to coordinate the balance between the laryngeal muscles in the process of articulation, and to promote the closure of the vocal folds and the effective vibration of the vocal cords. Commonly used to push the wall or pull the chair when breath-holding exercises; coughing and other methods.
Resonance training: The purpose is to regulate the relationship between the resonance cavities of the oral cavity, nasal cavity, chest cavity, etc., and to improve the efficiency of articulation.
Surgery
Purpose of Surgery
To improve or restore the quality of the patient’s voice, reduce aspiration, and relieve dyspnea through surgical methods.
Principles of Surgery
Vocal cord paralysis should be observed for at least 6 months before any surgical treatment to change the laryngeal structure, for vagus nerve injury, skull base injury, idiopathic vocal cord paralysis or even observed for more than 9 months without recovery before surgery.
The need for surgical approach should be based on the etiology, type of paralysis, duration, severity, special needs of the patient, and general condition.
Those who are still symptomatic after the above observation window and conditions permit should first undergo laryngeal reentry nerve repair surgery as early as possible.
Symptoms such as laryngeal obstruction, aspiration and choking caused by vocal cord paralysis should be treated promptly.
Surgery
Laryngeal nerve repair surgery
Applicable to unilateral vocal cord paralysis with clear nerve injury within 3 years, including patients with superior laryngeal nerve injury and posterior cerebral nerve injury.
Laryngeal frame surgery
Laryngeal frame surgery refers to the alteration of the laryngeal cartilage frame and the movement of the internal laryngeal muscles to relax, tighten, inwardly or outwardly extend the vocal folds in order to influence the closure of the vocal folds and the pitch, and to improve the quality of articulation and respiratory function.
The main procedures used to treat unilateral vocal cord paralysis are thyroid chondroplasty, arytenoid cartilage inversion, a combination of the two procedures and cricothyroid approach.
Vocal cord injection laryngoplasty
According to the causes and characteristics of vocal fold closure insufficiency, autologous or allogeneic materials are injected or filled into the parapharyngeal space to improve vocal fold closure and vocal fold vibration, and ultimately improve or restore the patient’s articulation and swallowing function. The procedure is easy to perform, effective and less invasive.
Vocal fold enlargement
Through surgical intervention on the arytenoid cartilage and vocal folds, the vocal folds can be enlarged to relieve dyspnea and minimize the damage to articulation and swallowing. It is suitable for patients with bilateral vocal cord paralysis.
Neuromuscular Tip Grafting
Indications: Bilateral laryngeal adductor paralysis caused by various reasons, narrow vocal folds, dyspnea and inability to maintain daily activities (neuromuscular tip transplantation on the posterior cricoarytenoid muscles).
Contraindication: Bilateral vocal fold immobilization due to bilateral cricoarytenoid joint stiffness. Loss of nerve branches required for bilateral hypoglossal nerve collaterals to each strap muscle due to trauma or scarring. Accompanied by other untreated airway obstruction. The patient is weak and cannot tolerate surgery.
Fixation of external displacement of the vocal cords
Indications: Incomplete paralysis of the recurrent laryngeal nerve on both sides, with various conservative treatments for more than half a year, with no or little progress, and unable to relieve respiratory distress. Fixation of cricoarytenoid joints on both sides, those who have difficulty in breathing.
Contraindications: patients after laryngeal tuberculosis or radiotherapy, due to the tough scar tissue or tissue fibrosis around the vocal cords protrusion, it is difficult to traction the vocal cords outward, which can easily lead to surgical failure. In these cases, laryngeal cleft pathway vocal cord external displacement fixation can be used. Accompanied by other untreated airway obstruction.
Other surgical treatments
Botulinum toxin vocal cord injection for bilateral vocal cord paralysis is a temporary treatment that can avoid tracheotomy by temporarily blocking the conduction of electrical impulses from the nerve endings and paralyzing the adductor muscles to abduct the vocal cords, which is suitable for patients with misdirected regeneration of the nerves.
Injections are given every 4 months, and other permanent treatments are still needed if the vocal cords do not regain motor function.
Surgical Complications
Respiratory obstruction
Local bleeding, hematoma compressing the vocal folds and trachea.
Postoperative laryngeal tissue edema, excessive inward movement of the vocal cords or excessive fat injection.
Insufficient expansion of the vocal folds due to bilateral vocal cord paralysis, or premature extubation due to laryngeal stenosis caused by postoperative scar contraction and adhesion.
De-tubing after tracheotomy, dry scabs blocking the cannula, etc.
Bleeding
Open neck surgery has the possibility of intraoperative and postoperative hemorrhage, especially in patients with repeated and multiple operations on the cervical thyroid gland, the anatomical markings of the neck are unclear, and it is easy to damage the blood vessels causing hemorrhage, and even internal carotid artery hemorrhage may occur.
Localized infection
Caused by foreign body reaction, laryngeal cavity mucosal trauma, and contamination of the operative field.
Misaspiration
Mechanical vocal fold enlargement with bilateral vocal cord paralysis is often associated with mild aspiration during swallowing in the early postoperative period.
Poor recovery or diminished voice function
Unilateral vocal cord paralysis with inappropriate opening position of the thyroid cartilage, resulting in high, posterior or anterior grafts, or inappropriate implant size, affecting postoperative articulation.
Pharyngeal fistula
A pharyngeal fistula is usually caused by injury from separation of the pyriform fossa during nerve repair or laryngeal frame surgery.
Implant Rejection
Almost all allogeneic materials have the possibility of foreign body reaction, but with the development of material science, the histocompatibility of the material is getting better and better, and the rejection reaction is extremely rare. It manifests as localized redness and swelling and protrusion of the foreign body.
Treatment of special cases
Tracheotomy
Purpose: to restore ventilation and improve hypoxia.
When asphyxia occurs, tracheotomy should be performed immediately to quickly relieve hypoxia and restore ventilation.
Complications: postoperative bleeding, pneumothorax and mediastinal emphysema, subcutaneous emphysema, difficulty in extubation, incision infection, etc.
Postoperative precautions: closely observe the respiratory status, make the airflow unobstructed. Intratracheal drip or nebulization at regular intervals. Single layer of gauze with physiological saline to humidify the cannula opening.
Treatment of aspiration
General treatment: including stopping transoral feeding, giving auxiliary diet, swallowing rehabilitation training methods.
Surgical treatment: Double vocal cord paralysis with severe aspiration can be treated surgically, using vocal fold narrowing surgery, pharyngeal separation surgery, total laryngectomy surgery and so on, depending on the degree of the patient.
Prognosis
Cured
Untreated
As the disease progresses, a small percentage of patients with unilateral recurrent laryngeal nerve incomplete paralysis may recover spontaneously.
In most patients, the symptoms may gradually worsen, affecting normal work and life, and may even cause serious complications such as acute laryngeal obstruction and aspiration pneumonia, leading to life-threatening respiratory distress.
After treatment
Patients with unilateral recurrent laryngeal nerve incomplete paralysis have better results, and some of them can be cured with active treatment; most of the other types of patients can effectively improve their symptoms and return to normal life without affecting their life expectancy.
Bilateral vocal cord paralysis of the vocal folds mechanical enlargement of the surgery, the operation will produce voice quality of varying degrees of decline, some need to be repeated several times the surgical side.
Hazards
Aspiration pneumonia can occur in those with bilateral paralysis due to complete loss of laryngeal mucosal sensation and accidental choking of food, drink and saliva into the lower respiratory tract.
Incomplete paralysis of bilateral recurrent laryngeal nerves can cause laryngeal obstruction due to the inability of both sides of the vocal cords to extend, which can cause asphyxiation in severe cases if not treated in time.
Bilateral paralysis due to the inability to form the ventricular band vocalization, vocal function is completely lost, can only excuse, pharyngeal and palatal resonance cavity composition speech.
Daily
Daily management
Dietary management
Eat more light and easily digestible food, pay attention to balanced nutrition, such as fresh vegetables and fruits.
Avoid unhygienic food, such as undercooked meat.
Try not to consume spicy food, such as onion, garlic, chili, etc. Try not to drink stimulating drinks, such as coffee, strong tea, lemonade, etc., to avoid irritating the throat.
Reduce the intake of acidic, greasy, high-fat and other irritating foods to prevent or reduce the occurrence of throat reflux disease.
Drinking an adequate amount of water helps to maintain the humidity of the vocal cords.
Life management
During the treatment and recovery phase of the disease, it is best to rest as much as possible and avoid strenuous activities that may aggravate symptoms.
Maintain adequate sleep every day, go to bed early and get up early to develop a regular routine.
Psychological support
Patients with laryngeal paralysis often show anxiety, low self-esteem and other emotions, family members should give care, comfort and companionship, encourage patients to establish confidence in overcoming the disease, and actively cooperate with the treatment.
Urge the patient to correct the bad habits of pronunciation and living habits.
Voice training
Adhere to voice training as prescribed by the doctor, including relaxation training, breathing training, articulation training, resonance training and so on.
Disease monitoring
Observe the recovery of voice after treatment.
Observe whether there is any complication after surgery.
Follow-up
Regular checkups will help to keep track of changes in your condition.
Follow the doctor’s instructions for outpatient follow-up.
Laryngoscopy and CT/MRI may be needed depending on the condition.
Prevention
Pay attention to production and life safety to avoid causing injury.
When viral infection occurs, it should be treated actively.
Adopt good living habits to improve the body’s resistance and prevent the occurrence of the disease.
Quit smoking, avoid inhaling second-hand smoke and reduce the irritation of smoke to the laryngeal cavity.
Quit drinking to avoid alcohol damage to the nervous system.
Actively treat trauma, tumor, neurological diseases and other primary diseases.