Laryngeal obstruction is a difficulty in breathing caused by obstruction of the laryngeal passage due to lesions of the larynx or its adjacent tissues. It is not an independent disease, but a symptom caused by various non-causal causes. Obstructive dyspnea caused by laryngeal obstruction often leads to hypoxia and carbon dioxide accumulation in the body. It is a common emergency and poses a risk of death by asphyxia. The laryngeal obstruction has more chances and progresses faster because of the narrow vocal chambers of young children, the laryngeal cartilage is not yet calcified, the laryngeal submucosa is loose, and the laryngeal nerves are not well developed and easily stimulated to cause spasm.
Etiology
1, inflammation: such as pediatric acute laryngitis, acute epiglottitis, acute laryngotracheobronchitis, laryngeal diphtheria, laryngeal abscess, retropharyngeal abscess, etc.
2, trauma: laryngeal contusions, cuts, burns, firearm injuries, high heat vapor inhalation or toxic gas inhalation.
3.Foreign body: foreign bodies in the larynx and trachea not only cause mechanical obstruction, but also can cause laryngeal spasm.
4.Oedema: laryngeal angioneurotic edema, allergic reaction to drugs, edema caused by heart and kidney diseases.
5.Tumor: laryngeal cancer, multiple laryngeal papilloma, laryngopharyngeal tumor, thyroid tumor.
6, malformation: laryngeal webbing, congenital laryngeal tinnitus, laryngeal cartilage malformation, laryngeal scar stenosis.
7.Vocal cord paralysis: bilateral vocal cord abduction paralysis caused by various reasons.
Clinical manifestations
1.Inspiratory dyspnea is the main symptom and feature of laryngeal obstruction. Anatomically, the vocal fold is formed between the edges of the vocal folds, which is the narrowest part of the larynx. When laryngeal obstruction is caused by the above-mentioned etiology, the airflow during inspiration pushes the oblique surface of the vocal cords downward and inward, which makes the vocal cords close to the midline and makes the already narrow vocal folds even narrower.
When the mucous membrane of the larynx is congested and swollen or the vocal cords are fixed due to the above mentioned causes, the vocal cords cannot make the normal abduction movement to open the vocal fissures, which aggravates the narrowing of the vocal folds and leads to further increase of dyspnea during inspiration. When exhaling, the airflow pushes the vocal cords upward, making the vocal fissure larger and still able to exhale gas, so the expiratory difficulty is lighter than that of inspiration, so the expiratory difficulty is not significant.
2, inspiratory laryngeal wheezing is an important symptom of laryngeal obstruction. When the laryngeal obstruction, the inhalation airflow, squeezing through the narrow vocal folds, forming a vortex of airflow to counterattack the vocal cords, causing the vocal cords to tremble and emit a sharp laryngeal wheezing sound. The size of laryngeal wheezing sound is positively correlated with the degree of laryngeal obstruction.
3.Inspiratory soft tissue depression Because the air does not easily enter the lungs through the vocal cords during inspiration, the thoracic and abdominal auxiliary respiratory muscles are compensated to strengthen the movement and expand the chest to help respiration, but the lung lobes cannot expand accordingly, resulting in increased negative pressure in the thoracic cavity, causing inspiratory depression in the chest wall and its surrounding soft tissues (such as the neck p chest and abdomen), and the main sites of inspiratory depression are.
①superior sternal fossa ;
②superior and inferior clavicular fossa;
③ rib cage;
④Subclavian and upper abdomen. The degree of depression often varies with the degree of dyspnea. The degree of depression often varies with the degree of dyspnea. In children, the depression sign is more obvious because of the weak muscle tone.
4. Hoarseness When the lesion involves the vocal cords, the voice becomes hoarse and even loses its sound.
5, hypoxic symptoms mainly manifested as cyanosis, cold extremities, irritability. At the early stage of laryngeal obstruction, the body can still tolerate, without obvious symptoms of hypoxia. With the prolongation of the obstruction and the aggravation of the degree, fast and deep breathing and accelerated heart rate start to appear. If the obstruction is further aggravated, the body starts to appear hypoxia and restlessness, irritability, cyanosis, and head tilting back during inspiration. At the end, there are cold sweat, weak pulse, rapid or irregular, fast and shallow breathing, convulsions, coma, heart failure, and finally coma and death.
[Respiratory distress classification
In order to distinguish the severity of the disease and accurately grasp the principles of treatment and the timing of surgery, the inspiratory dyspnea caused by laryngeal obstruction is divided into 4 degrees.
First degree: no respiratory distress when quiet. When active or crying, there is mild inspiratory dyspnea.
Second degree: Mild inspiratory dyspnea in quiet time, laryngeal tinnitus in inspiratory period and soft tissue depression around the thorax in inspiratory period, aggravated by activity, but it does not affect sleep and eating, and there are no symptoms of hypoxia such as irritability. Pulse is still normal.
Third degree: dyspnea is obvious in the inspiratory period, laryngeal tinnitus is very loud, soft tissue depression in the upper sternal fossa, upper and lower clavicular fossa, upper abdomen and intercostal area is significant in the inspiratory period (four concave signs). The symptoms include irritability, difficulty in sleeping, reluctance to eat, and rapid pulse rate due to lack of oxygen.
Fourth degree: extreme difficulty in breathing. Due to severe hypoxia and increased accumulation of carbon dioxide, the patient is restless, hands and feet moving, cold sweat, pale or cyanotic face, loss of orientation, irregular heart rhythm, weak pulse, decreased blood pressure, incontinence, etc. If not resuscitated in time, death may occur due to asphyxia resulting in respiratory and cardiac arrest.
Diagnosis
The correct diagnosis can be made quickly by history and symptoms. In mild cases, laryngoscopy is performed to determine the laryngeal lesion; in severe cases, life is firstly rescued and the cause of respiratory distress is then investigated in detail and subsequent treatment is decided.
The dyspnea caused by laryngeal obstruction must be clinically differentiated from expiratory and mixed dyspnea caused by bronchial asthma and tracheobronchitis.
Treatment
For patients with acute laryngeal obstruction, it is necessary to race against time and to quickly relieve respiratory distress to avoid asphyxia or heart failure. Treatment should be decided according to the cause, degree of dyspnea, patient condition and objective conditions. Patients with acute laryngeal obstruction must be treated as soon as possible to resolve the respiratory distress and get the patient out of hypoxia. According to the degree of respiratory distress, drug or surgical treatment is used respectively. If tracheotomy is performed, except for emergency and special cases, the family or the patient should be informed of the risks of the operation and sign the informed consent form.
First degree: clarify the cause and treat the cause. Non-specific inflammation is treated with antibiotics and glucocorticoids.
Second degree: non-specific inflammation, antibiotics and glucocorticoid treatment, prepare for tracheotomy; early removal of respiratory foreign body; laryngeal tumor caused by tracheotomy can be considered.
Third degree: those caused by non-specific inflammation, laryngeal obstruction for a short period of time, treated with drugs and oxygen under close observation, and ready for tracheotomy; if there is no significant improvement after treatment or the patient’s general condition is poor, tracheotomy should be performed early. If it is caused by tumor, tracheotomy should be performed immediately.
Fourth degree: tracheotomy should be performed immediately, and in very urgent cases, various means such as cricothyrotomy or puncture should be performed first to immediately improve the state of respiratory distress, and then change to formal tracheotomy after the condition is stabilized.