Cough - Definition and Mechanisms

Cough
Cough is a symptom of the most common disease in which the prevalence was found in about 15% in children and 20% in adults. One out of ten patients who visited the doctor's office each year has a chief complaint of cough. Coughing can cause bad feelings, sleep disorders, affecting daily activities and reduce quality of life.

Cough is a complex physiological reflex that protects the lung from mechanical trauma, chemical and temperature. Coughing is also a natural defense mechanism of lung airway to keep it clean and open to the street:
Prevent the entry of foreign objects into the respiratory tract.
Remove foreign objects or abnormal secretions from the respiratory tract.
Coughing becomes physiologically when perceived as a nuisance. Such a cough is often a sign of a disease within or outside the lungs and sometimes are the early symptoms of a disease. Cough may be very significant on the transmission of disease through the air (air-borne infection). Cough is one of the symptoms of respiratory tract diseases in addition to tightness, wheezing, and chest pain. Often the cough is a problem faced by physicians in their daily work. The reason is very diverse and the introduction of the pathophysiology of cough would be very helpful in establishing the diagnosis and prevention of people with coughs. Research shows that in patients with acquired chronic cough 628 cough up to 761 times / day. Patients with pulmonary TB coughs number about 327 times / day and patients with influenza-even up to 154.4 times / day.
Epidemiological studies have shown that many chronic cough associated with smoking. Twenty-five percent of those who smoked 1 / 2 pack / day will have to cough, while the patients who smoked one pack per day will be found to be approximately 50% of chronic cough. Most of the heavy smokers who smoked 2 packs / day will complain of chronic cough. Large-scale research in the U.S. also found that 22% of non-smokers also suffer from cough, among others, caused by chronic diseases, air pollution and others. Coughing can also cause various complications such as pneumothorax, pneumomediastinum, headache, fainting, disc herniation, inguinal hernia, broken ribs, bleeding subkonjungtiva, and urinary incontinence.

Definition
Cough in Latin called tussis is a reflex that can occur suddenly and often repeated that aims to help clear mucus from the respiratory tract of, irritants, foreign particles and microbes. Coughing can happen voluntarily or involuntarily.
Coughing is a reflex action in the respiratory tract that is used to clean the upper airways. Chronic cough lasts more than 8 weeks are common in the community. Causes include smoking, exposure to cigarette smoke, and exposure to environmental pollutants, especially particulates.

Mechanism of Occurrence of Cough
Cough starts from a cough receptor stimulation. These receptors are non-myelinated nerve fibers in the form of finely located both inside and outside the thoracic cavity. Located within the thoracic cavity, among others, contained in the larynx, trachea, bronchus, and pleura. Will decrease the number of receptors on the branches of a small bronchus, and a large number of receptors in the can in the larynx, trachea, carina and bronchus branching region. The receptors are also found even in the ear canal, stomach, hilum, paranasalis sinus, pericardial, and diaphragm.

Mechanism Of Cough

Afferent fibers are the most important branch of the vagus on the drain stimuli from larynx, trachea, bronchus, pleura, stomach, and also stimulation of the ear through the Arnold branch of the vagus. Trigeminal nerve stimulation of the sinus paranasalis channel, glosofaringeus nerve, excitatory channel of the pharynx and channel phrenic nerve stimulation of the pericardium and diaphragm.

By excitatory afferent fibers was taken to the cough center located in the medulla, near the center of the respiratory and vomiting centers. Then from here by afferent fibers of the vagus, phrenic nerve, intercostal and lumbar nerves, the trigeminal nerve, facial nerve, nerve hipoglosus, and others headed to the effector. These effector standing of the muscles of the larynx, trachea, bronchi, diaphragm, intercostal muscles, and others. In the area of ​​this effector mechanism of cough ensued.

Phase of Cough

Basically the mechanism of cough can be divided into four phases, namely:


1. Phase irritation
Irritation of one sensory vagus nerve in the larynx, trachea, large bronchi, or afferent fibers from the pharyngeal branch glosofaringeus nerve can cause coughing. Coughing also arise when the cough receptors in the lining of the pharynx and esophagus, pleural cavity and external ear canal is stimulated.

2. Phase of inspiration
In the inspiration phase of the glottis is wide open due to reflex muscle contraction abduktor aritenoidea cartilage. Inspiration occurs in and quickly, so the air quickly and in large quantities into the lungs. This is accompanied terfiksirnya rib due to muscle contraction under the thorax, abdomen and diaphragm, so that the lateral dimension enlarged breasts lead to increased lung volume. The entry of air into the lungs by the number of lots of benefits that will strengthen the expiratory phase resulting in faster and stronger and reduce the air cavity is closed so as to produce a potential cleaning mechanism.

3. Compression phase
This phase begins with the closing of the glottis due to contraction of the adductor muscle aritenoidea cartilage, glottis closed for 0.2 seconds. In this phase the intrathoracic pressure rises to 300 cmH2O to place an effective cough. Pleural pressure remained elevated for 0.5 seconds after the glottis open. Coughing can occur without glottis closure because of expiratory muscles to increase intrathoracic pressure although the glottis remains open.

4. Expiratory phase / expulsion
In this phase the glottis opens suddenly due to active contraction of expiratory muscles, so there was spending large amounts of air at high speed accompanied by spending foreign objects and other materials. Movement glottis, respiratory muscles and the branches of the bronchus is important in the mechanism of cough phase and this phase of cough is actually happening. Cough sound varies greatly due to vibration secretions in the respiratory tract or the vibration of vocal cords

Cough - Causes and Complications
Management of Cough