Introduction to cough
Cough is a critical and a complex mechanism, which helps in ‘protecting the respiratory system’. It occurs due to the irritation and inflammation of the upper respiratory tract, which includes throat and windpipe.
This irritation may be caused due to infections like
Cough is a physiological defense mechanism and a resultant action to clear the airway from mucus, phlegm and irritants like smoke, dust etc. The reflexes of cough are controlled by the interaction of afferent and efferent nerves in the cough centers of the brain.1
Classification of cough
Cough can be categorized based on the duration.
- Acute cough—Acute cough lasts for about 3 weeks. This may be caused due to common cold, asthma, bronchitis, chronic obstructive pulmonary diseases or lower respiratory infection.2
- Subacute cough—Subacute cough lasts for about 3–8 weeks. This may be due to postinfectious cough (occurs after an acute respiratory infection), sinusitis and asthma.
- Chronic cough—Chronic cough lasts for more than 8 weeks and often caused due to multiple conditions. The exact cause can be known through a detailed medical history, physical examination and chest radiograph of the patient.
Cough can also be divided as follows:
- Dry cough—A dry cough develops when there is an inflammation in the upper respiratory tract. There is no phlegm production, but a tickling feeling is felt which results in coughing.
- Chesty cough—In this kind of cough, phlegm may be produced in response to an infection or may not be produced if the passageways of the lungs swell due to infection.
Symptoms of cough
Cough is a ‘symptom’ of many conditions like, cold, flu etc. In these conditions, cough cause irritation in the chest. In conditions like bronchitis, cough may develop after other symptoms have developed. A cough developed due to a viral infection often takes 7–10 days to be cured.
If the symptoms are severe, then it is necessary to see a physician to prevent secondary infections.
Diagnosis of cough
Acute cough is diagnosed based on its association with common cold or lower respiratory tract infection. Diagnosis of subacute cough is based on whether the cough has followed a respiratory infection.
Chronic cough is based on the following:3
- Medical history—This is very important to determine whether the patient is suffering from disease conditions like tuberculosis, history of cancer or acquired immunodifiency syndrome. Another important point is, to know whether the patient is a smoker.
- Chest radiography—A radiography of the chest should be done. If any abnormality is noticed then a CT or Computed tomography, bronchoscopy can be conducted.
If an infection is observed, then a microbiological analysis may be suggested.
Treatment of cough
Cough can be treated successfully upon proper diagnosis. Treatment of cough involves different kinds depending on the type. Acute and subacute cough due to common cold can use antihistamine- decongestant and intranasal ipratropium.
Treatment with oral or inhaling corticosteroids and beta-agonists can be suggested to patients suffering from subacute or chronic cough.
Chronic cough due to cigarette smoking and irritants should avoid these and antibiotics may be prescribed.4
Cough can be managed by:
- Proper treatment and appropriate medications
- Acute cough is usually self-limiting but requires medical intervention if it is severe
- Chronic cough can be managed after knowing the underlying disease condition and getting treated
- Stopping cigarette smoking
- Avoiding irritants and other pollutants which cause cough
- Irwin RS, Boulet LP, Cloutier MM, Fuller R, Gold PM, Hoffstein V, et al. Managing cough as a defense mechanism and a symptom. A consensus panel report of the American College of Chest Physicians. Chest. 1998; 114(Suppl 2): 133S–181S.
- Braman SS. Chronic cough due to acute bronchitis: ACCP evidence-based clinical practice guidelines. Chest. 2006; 129(1 Suppl): 95S–103S.
- Irwin RS, Madison J. Primary Care: The Diagnoses and Treatment of Cough. NEJM. 2000; 343(23).
- Linder JA, Sim I. Antibiotic treatment of acute bronchitis in smokers: A systematic review. J Gen Intern Med. 2002; 17: 230–234.