Everybody,
at some time, has a cough. It is an explosive expiration which
provides a means of clearing the throat, trachea and bronchi
of secretions, irritants and foreign bodies. It can be voluntary
or involuntary. The mechanism involves the closing of the glottis,
a trapdoor-like tissue between the throat and the trachea (wind
pipe), a build up of pressure in the chest, and a re-opening
of the glottis to release the built up pressure as a cough.
The lining of the respiratory tract is sensitive and any irritation
can give rise to a cough. These irritations include inflammation,
chemicals, sudden changes in temperature, external pressure
and dust. Inflammation is usually the result of infection, either
viral or bacterial. The commonest chemical irritant is cigarette
smoke, though any fumes and smoke can result in a cough. Hot
air and cold air can both trigger off cough, as can mechanical
factors such as dust or inhaled foreign bodies. Pressure on
the bronchial tubes or trachea from other organs can give rise
to cough as can the presence of tumours and dilated major blood
vessels. Cough is invariably present in chronic lung conditions
such as asthma (see Asthma) and bronchitis (see Bronchitis).
A cough is also a common feature of chronic heart failure where
fluid builds up in the lungs. Sometimes a cough is dry, sometimes
productive of sputum, which, in turn can be clear or infected
and purulent - as in bronchitis and pneumonia. A transient,
minor, non-productive cough is usual with minor upper respiratory
tract infections ( see Coryza). A severe, chronic cough producing much sputum may be symptomatic of chronic bronchitis. A chronic cough is not to be ignored and a patient should always consult a doctor about it. Coughing up blood is always a reason to see the doctor urgently although the cause may be quite innocent. Sometimes, in virus infections, the cough can last for weeks. If, during an attack of influenza (see Influenza), the sputum becomes coloured the doctor should be consulted. A common cause of cough is sinus infection where, particularly at night, infected mucous runs down the back of the throat, is coughed up, and may be mistaken for purulent sputum coughed up from the chest. Many coughs have a particular pattern e.g. the night cough of asthma, the morning smoker's bronchitis.
Common sense is required as a large number of coughs, the simple, uncomplicated coughs that last only a few days, require only simple treatment and not medical consultation. The management of the cough depends entirely on its nature and cause. If the cough lasts more than a few days and there is infected sputum the doctor may well prescribe antibiotics. For the ordinary dry irritating cough, steam inhalations will help as will simple linctus and proprietary cough medicines, particularly those containing a cough suppressant such as codeine. Even a minor dry cough can cause loss of sleep and eventual exhaustion. When the cough is productive, the person should be encouraged to cough up the sputum with the help of hot drinks, expectorant medicines etc. This particularly applies to the elderly and infirm in whom pneumonia can result if the lungs are not cleared and aerated. Coughing is not only a sign of infection but is also the major way in which infections such as coryza and influenza are spread. So, in these circumstances, keep your cough to yourself! |
