Cough is an unconditioned reflex act that occurs in response to stimulation of specific receptors and is manifested by forced exhalation after a period of tension of the respiratory muscles. The symptom is usually caused by diseases of the respiratory system, but can develop when inhaled toxic substances, foreign bodies, congestion in the lungs. To identify the cause of the cough, x-rays, spirometry, fibrobronchoscopy, and laboratory tests are performed. For the relief of symptoms, antitussive and expectorant drugs, mucolytics are used.
A cough is a forced exhalation through the mouth with characteristic sounds. Often it is preceded by a feeling of soreness or scratching in the throat, tightness in the chest. In most cases, the coughing act is accompanied by pain in the chest. Cough may result in the release of yellow-green, "rusty", glassy and other types of sputum, typical of certain diseases. With a prolonged coughing attack, reflex vomiting is sometimes possible, the blueness of the nasolabial triangle due to hypoxia.
More often, coughing occurs against the background of other symptoms of damage to the respiratory system: sore throat, chest, nasal congestion. When the vocal apparatus is involved, the symptom is combined with hoarseness up to aphonia. In severe illness, coughing shocks can follow one after another without interruption, which is called a cough reprise. The presence of a persistent cough in a patient, especially with the release of purulent or bloody sputum, a violation of the general condition is a direct indication for a visit to a pulmonologist.
The cough act is a complex reflex defense mechanism that is necessary to cleanse the airways of foreign bodies, toxins and excess mucus. The cough reflex begins with irritant receptors in the larynx and tracheobronchial tree, which are innervated by fibers of the vagus nerve. The most sensitive to external influences are the vocal cords, the epiglottis, the bifurcation zone of the trachea into the bronchi. The receptors respond to mucus, chemicals, pollutants, and large foreign bodies.
Excitation from irritant nerve endings is directed to the cough center located in the medulla oblongata and to the neurons of the reticular formation. These structures are responsible for the coordinated work of all muscle groups involved in the act of coughing. The first phase of the reflex includes a deep short breath lasting about 2-3 seconds, which is accompanied by a spasm of the muscles of the larynx and glottis, an increase in the tone of the muscles of the bronchi. Intrathoracic pressure can reach 14mm Hg. Art.
This is followed by a sharp contraction of the abdominal muscles, the diaphragm to overcome the increased resistance with a rapid exhalation through the mouth. The air flow velocity during coughing reaches 50-12 m/s, which is 25-3 times higher than during quiet breathing. Together with a stream of air, droplets of mucus, dust, and foreign particles are removed from the bronchopulmonary system. Forced expiration ends a single coughing act, but with excessive irritation of the receptors, the reflex can be repeated many times.
There are no sensitive nerve endings in the lung parenchyma itself, therefore, with primary lesions of the lungs, coughing indicates the progression of the disease, the involvement of the bronchi or pleura in the pathological process. The cough reflex can also be formed in cardiac pathology, which contributes to an increase in pressure in the pulmonary vascular system. This leads to the release of the liquid part of the blood into the alveoli and interstitial tissue, which ends with irritation of the receptors, an intense cough, which is aggravated in a horizontal position.
Cough is not a specific sign of any disease, but its diagnostic value increases with the identification of specific features of the appearance of a symptom. When classifying, they are guided by the presence or absence of sputum, timbre, frequency, duration, frequency of occurrence during the day. The most common and important for diagnosis is the allocation of varieties of coughing act, depending on the presence of a secret:
There is a classification according to volume and timbre, there is a "barking" cough, characteristic of laryngitis, false croup in children, deaf weakened in chronic obstructive bronchitis, silent, indicating the destruction of the vocal cords. A bitonal cough is distinguished into a separate category, in which an additional high tone sounds, most often indicating the development of tumorous bronchoadenitis in childhood.
In diagnostic terms, it is important to classify the symptom according to the time of manifestation: morning cough is more often detected in smokers and asthmatics, nocturnal attacks are pathognomonic for tuberculosis and cardiac asthma. With inflammation of the respiratory tract, there is no connection between the symptom and the time of day. According to the mechanism of symptom formation, central (neurotic), associated with direct excitation of reflex zones in the brain in neurosis, and reflex cough, caused by irritation of the nerve endings of the respiratory system, upper esophagus, are distinguished.
The symptom occurs in healthy people when inhaling air polluted with pollutants, pungent odors. Coughing is usually associated with damage to the upper respiratory tract. There are the following causes of superficial cough:
Intense cough paroxysms without sputum production are most characteristic of the localization of the pathological process in the lower respiratory tract. The symptom can be combined with chest pain, shortness of breath. An attack of dry deep cough is provoked by the following reasons:
Normally, after coughing, a tiny amount of clear mucus is separated from a person, but more often a wet cough is caused by damage to the respiratory system. Usually, after coughing up sputum, the patient feels relief. Common causes of cough with phlegm:
Cough paroxysms with a characteristic loud (“barking”) sound are observed when the pathological process spreads to the mucous membrane of the larynx and the vocal cords. The development of a barking cough is most often caused by:
The most common causes of coughing are diseases of the respiratory system, so the examination is organized by a pulmonologist. To make a diagnosis, it is necessary to use a complex of instrumental methods and laboratory tests that are aimed at identifying morphofunctional disorders and signs of pathological processes. The most diagnostic value are:
When respiratory causes of cough are excluded, additional diagnostic methods are used: contrast radiography of the esophagus, ECG, ultrasound of the heart. To determine the degree of respiratory disorders, the gas composition of the blood is determined. In case of violations of the function of external respiration, spirography is performed with an assessment of the main indicators - forced expiratory volume, vital capacity of the lungs. Some patients need to consult an immunologist-allergist.
Inhalations for coughing
To reduce the frequency of coughing attacks, patients are advised to avoid strong odors, sudden changes in air temperature, and limit the consumption of spicy foods and carbonated drinks. A plentiful warm drink is recommended: teas, herbal teas, dried fruit compotes. In order to clean the respiratory tract and stimulate sputum discharge, gargling with antiseptic solutions, inhalations are used. Persistent cough that lasts more than 2-3 days, accompanied by chest pain or shortness of breath, is an indication for seeking medical help and determining its cause.
Medical tactics depend on the underlying disease, the intensity and duration of cough paroxysms. With a superficial cough, softening inhalations and rinsing are sufficient, a deep dry or wet cough requires the use of specific drug therapy. Treatment is supplemented with physiotherapeutic methods, chest massage to facilitate expectoration of sputum. Taking into account the leading cause of cough, the doctor prescribes various groups of drugs: