Cough is a powerful physiological reflex of the body that serves as a mechanism of defense of the respiratory system. It is the shield of our respiratory system against harmful particles and microorganisms trying to harm the lungs and the body.
Along the airways, which transfer the inhaled air from the nose and mouth to the lungs, there are cough receptors that are irritated by a variety of stimuli (foreign bodies, smoke, fumes, cold, etc.) and cause the cough reflex.
Cough is one of the most common symptoms.
Cough lasting less than 3 weeks is defined as acute, while chronic cough is the one that lasts more than 3 weeks and then it is necessary to investigate the cause. Cough can be dry or productive, i.e. accompanied by sputum elimination.
There are many causes of cough:
- Upper and lower respiratory infections: common cold, flu, pharyngitis, laryngitis, sinusitis, acute bronchitis, pneumonia, tuberculosis, , chronic bronchitis,
- bronchial asthma
- Chronic obstructive pulmonary disease,
- Gastroesophageal regurgitation,
- Lung malignancy
- Interstitial lung diseases
- Congestive heart failure
- Pulmonary embolism
- Cystic fibrosis
- Antihypertensive therapy
The most frequent causes of chronic cough are the following:
Upper airway cough syndrome (postnasal drip syndrome): The most common causes of chronic cough from the upper respiratory tract. It is caused due to nasal secretions flowing towards the back of the throat and triggering the cough reflex. It usually worsens when the patient is lying down e.g. at night. It makes you feel like you’re constantly going to have to clean your throat. Postnasal runny nose may develop in people with allergic rhinitis, vasomotor rhinitis, common cold, and sinusitis. The absence of the above symptoms does not exclude the diagnosis of the disease, often the empirical treatment, if excluded other causes of cough is applied.
Asthma Cough may be the only symptom with which asthma manifests. In these patients, it is often difficult to diagnose the disease because they may have normal clinical examination and normal respiratory function as estimated by spirometry. These patients may need further tests such as a bronchial challenge test to confirm the diagnosis of bronchial asthma.
Gastroesophageal reflux is a common cause of chronic cough, due to reflux of gastric contents especially at bedtime. Coughing is combined with heartburn and reflux. It can also be post-meal (released 10 minutes after a meal) or linked to body position where the stomach or diaphragm is pressed. Reflux of gastric contents causes respiratory irritation and coughing. In 40% of these patients, however, the above symptoms may be silent and special examinations may be needed by a gastroenterologist.