Introduction:
Coughing is important to clear the throat and airways from foreign particles. A cough is referred to as a chronic cough when it lasts for eight weeks or more in adults and more than four weeks in children. It is a health problem that results from other health conditions. Coughing is one of the methods used by our body to keep us healthy, but a cough that lasts for a long time can affect our well-being in many ways. Cough can have a great impact on human life. It keeps people awake at night and can distract them from work and social life.
What Causes Chronic Cough?
There are various medical conditions related to chronic cough. These include respiratory conditions such as-.
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Asthma:
Cough-variant asthma is one of the most frequent causes of chronic cough. This may come and go with the seasons, after getting exposed to cold air or certain chemicals or occur after an upper respiratory tract infection. In cough-variant asthma, cough is the main symptom. Coughing along with breathing difficulty can occur day and night.
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Gastroesophageal Reflux Disease (GERD):
The stomach acid flows back into the tube that connects the stomach and the throat. The constant irritation can result in chronic coughing, which in turn worsens gastroesophageal reflux disease.
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Post-nasal Drip:
When there is increased mucus production in the nose or sinus, the mucus can drip down the back of the throat and trigger the cough reflex. This condition is called upper airway cough syndrome.
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Chronic Obstructive Pulmonary Disease:
Chronic inflammatory disease refers to the obstructed airflow from the lungs; it includes emphysema and chronic bronchitis. Emphysema causes shortness of breath and damages the air sacs in the lungs.
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Blood Pressure Drugs:
Angiotensin-converting enzyme (ACE) inhibitors recommended for heart failure and high blood pressure are known to cause a chronic cough in some people.
Other causes that are responsible for causing chronic cough include-
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Cystic fibrosis.
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Aspiration.
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Bronchiectasis (dilated airways).
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Laryngopharyngeal reflux (stomach acid flows up into the throat).
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Nonasthmatic eosinophilic bronchitis (airway inflammation not caused by asthma).
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Idiopathic pulmonary fibrosis (chronic scarring of lungs due to unknown cause).
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Sarcoidosis (collection of inflammatory cells, most commonly in the lungs).
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Cough hypersensitivity syndrome (CHS - Troublesome cough triggered by a low level of thermal, chemical, or mechanical exposure).
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Smoking.
What Are the Symptoms of Chronic Cough?
Common symptoms of chronic cough include:
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Heartburn.
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Hoarse voice.
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Runny nose.
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Stuffy nose.
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Headache.
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Dizziness.
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Chest discomfort and soreness.
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Frustration and anxiety.
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Sleep loss.
More severe symptoms include:
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High fever.
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Cough up blood.
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Night sweats.
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Shortness of breath.
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Persistent chest pain.
What Are the Complications of Chronic Cough?
Coughing continuously can hurt the muscles and break the ribs. The most prominent complications are extreme tiredness and lack of sleep. Other complications include:
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Urinary incontinence (loss of bladder control).
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Hernia.
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Syncope (fainting).
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Subconjunctival hemorrhage (minor bleeding in the eye).
What Is the Pathophysiology of Chronic Cough?
A cough occurs in three stages-
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Inhalation Phase:
In this phase, it generates enough volume for an effective cough.
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Compression Phase:
A compression phase refers to the pressure against a closed larynx by the contraction of the chest wall, abdominal muscles, and the diaphragm.
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Expiratory Phase:
This phase refers to when the glottis opens, resulting in high airflow. A cough can be voluntary or involuntary in action. A voluntary cough is characterized by cough inhibition or initiation. An involuntary cough is stimulated by vagal afferent nerves. The stimulation of cough receptors in the airway impulses travels through the vagus nerve to the cough center in the medulla, which is controlled by higher cortical centers. The afferent signals travel through the phrenic and spinal motor nerves to the expiratory muscles, resulting in the production of coughing.
What Are the Diagnostic Approaches for Chronic Cough?
The initial approach is carried out with a detailed history and focused physical examination. Many types of tests are performed to diagnose the causes. These include-
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Laboratory Testing:
This test helps to identify the presence of bacteria that are known to cause coughing, and these involve blood tests. Other tests involve the examination of mucus that is coughed up.
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Imaging Test:
These tests include X-rays, computed tomography (CT), magnetic resonance imaging (MRI), nuclear testing, and ultrasound. X-rays are taken to rule out the causes of chronic cough, such as lung diseases, lung cancer, and the build-up of fluids in the areas that help in breathing. All other tests provide clear, detailed areas of the body that affect breathing.
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Lung Function Tests:
These are also called pulmonary function tests that show how well the lungs are functioning. It measures the pattern of inhaling and exhaling. Spirometry is also one type of lung function testing, whereas others are lung volume testing, gas diffusion, and the six-minute walk test.
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Scope Tests:
These tests are taken with the use of a scope. It is an instrument that combines a camera and a long tube. A scope is passed into certain areas of the body to rule out the reason for chronic cough. A scope can be passed;
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Through the nose into the voicebox, area to look for signs of post-nasal drip, acid reflux, and abnormalities in the upper airway.
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Up through the nostrils for signs of infections or blockages in the nasal passages.
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Down the esophagus and into the stomach to measure the level of gastric acid in causing gastroesophageal reflux disease.
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Down the windpipe and into the bronchial tubules to check for any signs of blockages or infections in the lung.
What Are the Treatment Approaches for Chronic Cough?
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The treatment for chronic cough is based on the underlying cause.
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Post-nasal drip is the most common cause of chronic cough. Decongestants and Antihistamines are recommended, which help to dry up the secretions and reduce the inflammation that causes post-nasal drip. Decongestants and nasal steroid sprays also help to overcome the post-nasal drip.
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In the case of gastroesophageal reflux, the following measures are recommended.
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Avoid foods that cause gastroesophageal reflux, such as citrus fruits, chocolate, high-fat foods, tomato-based foods, caffeine, and peppermint.
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Eating frequent small meals a day.
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Avoid lying until two hours after eating.
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Sleeping with the head raised with a pillow.
Conclusion:
The prognosis depends on the underlying cause and the medical condition. Chronic cough can be a symptom of chronic obstructive pulmonary disease, fibrosis, asthma, and many other pulmonary diseases. If the patient presents with any of these symptoms, consulting with a health care provider improves the condition and in better prognosis. Therefore, an interprofessional team approach is aimed at providing proper diagnosis and ruling out the exact cause of the condition, and aiding in the necessary treatment.
