Tuesday, August 6, 2013

Cough

A cough is an action with which the body throws away the substances that are irritating to the throat.  Cough is a reflex which keeps a person’s throat and airway clear of mucus (sticky substance), irritants such as foreign particles and germs.  A cough is only a symptom, not a disease, and often the importance of your cough can be determined only when other symptoms are evaluated

 A person can choose to cough (a voluntary process), or the body may cough on its own (an involuntary process). Coughing has its distinctive sound and occurs in mainly three phases. Inhalation (breathing-in) is followed by a forceful exhalation (breathing out) and a consequent violent release of air from the lungs. The force developed during the process helps in the elimination of mucus and foreign materials.

 If one is found coughing frequently, it might indicate the presence of a disease. So, instead of suppressing it with cough suppressants, it is advisable to consult the doctor to avoid further complications.

Types of cough:

As can be seen there are many causes for cough. Basically cough is classified into two categories, acute and chronic. This classification is based on the duration 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 (COPD which is like asthma) or lower respiratory infection.

Acute coughs can be of 2 types: infectious (caused by an infection) and noninfectious causes. Infectious causes of acute cough include viral upper respiratory infections (the common cold), sinus infections, acute bronchitis, pneumonia, and whooping cough. Non-infectious causes of cough include chronic conditions such as chronic bronchitis, emphysema (lung disease causing shortness of breath), asthma, and environmental allergies.

    Sub-acute cough: Sub-acute cough lasts for about 3–8 weeks. This may occur after an acute respiratory infection, sinusitis (inflammation/redness of sinus) 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.

Chronic cough is a cough that stays for long time. It is not a disease in itself; but a symptom of an underlying condition. Some common causes of chronic cough include asthma, allergic rhinitis (runny nose), sinus problems (sinus infection), and sometimes some acidity problems. In rare occasions, chronic cough may be due to foreign objects into the lungs (usually in children). It is very important to see a doctor who may order a chest X-ray if a chronic cough is present.

Cough can also be divided as follows:

    Dry cough: A dry cough develops when there is an inflammation (redness/pain etc) in the upper respiratory tract. There is no phlegm (mucus ) production, but a tickling/irritation is felt which results in coughing.

    Chesty cough: In this kind of cough, phlegm (mucus) may be produced in response to an infection or may not be produced if the passageways of the lungs swell due to infection.

Types of Cough

Chesty Cough

It is a symptom of chest congestion (cough build up). A person suffering from cold or influenza usually suffers from chesty cough, which contains a lot of phlegm (mucus). This cough is said to be useful since it coughs out the mucus (which traps irritants/germs) from the chest, lungs and air passages. If the phlegm/mucus remains in the chest, it can lead to high fever as well as vomiting. So, physicians suggest an expectorant (cough syrup) in this case, which thins down the phlegm and makes coughing it up simpler. 

Whooping Cough

This cough is caused by a bacterial (germs) infection and is highly contagious. Commonly prevalent among children, it causes long spell of coughing in which the sufferer cannot breathe adequately. At times, the coughing becomes so intense that it leads to vomiting and in extreme cases causes the blood vessels of the eye to break.

Chronic Cough

Chronic cough is mostly seen in people suffering from certain health conditions such as cystic fibrosis (disease where sticky mucus builds up in lungs & other organs), chronic obstructive pulmonary disease (COPD like asthma), emphysema (lung disease causing shortness of breath), or bronchitis. In such a case, a person coughs involuntarily (body’s response) due to inflamed or blocked air passages. It is also the body’s own mechanism to exchange oxygen. Chronic cough differs according to the underlying disease-example, if a person is suffering from chronic obstructive pulmonary disease, the cough may be dry, while in case of cystic fibrosis (disease where sticky mucus builds up in lungs & other organs), the cough may be full of mucus.

Cough due to Asthma & Allergies

A person suffering from asthma generally experiences a dry, non-productive cough (no mucus), which is usually accompanied by a wheeze or crackling sound. Even in case of allergy, which is caused due to the narrowing of air passages by pollutants such as pollen, cigarette smoke, animal dander or products with a strong fragrance, one experiences coughing spells similar to asthma. Asthma as well as allergy can be cured by an inhaler or long-term treatment.

Common Cold Cough

When a person is suffering from common cold or influenza, he first experiences a spell of non-productive cough (no mucus)followed by a productive one (with mucus thrown out). With viral infection, the mucus production gets affected so the mucus becomes stickier and clings to the lungs making it difficult to be thrown out during coughing so coughing becomes exhaustive.

Symptoms of cough:

Signs and symptoms of coughing and the duration of cough help to determine the cause of cough.

Signs and symptoms of cough are listed below:

·         In cough due to infection symptoms are - fever, chills, body aches, sore throat, nausea, vomiting, headache, runny nose, night sweats and sputum or mucus.

·         Non-infectious cough symptoms are - Exposure to certain environmental factors like pollen, chemicals/irritants or fragrances.

·         If a cough is related to environmental irritants/allergy, it will worsen when exposed to the allergy causing agent and environment.

·         If a person has a smoker's cough, it may improve or worsen depending on whether he quits or continues to smoke.

·         In case of asthma or bronchitis, the cough is persistent and becomes worse with certain locations.

·         If a cough is caused by chronic sinus infections, symptoms are – headache, runny nose, etc.

·         If a cough is associated with medications, like heart care medications such as (ACE) inhibitors, the cough often begins after starting the medication but can come on at any point during the use of the medication. The cough is often dry and improves when the medication is stopped.

·         A cough associated with GERD (acidity problem where the acid from stomach comes up) is accompanied by a sensation of heartburn. This type of cough worsens during the day or when lying down/sleeping. In this case most people will report improvement in their cough when GERD/acidity is treated properly.

·         If a cough is a warning sign of an underlying cancer, the person may have a group of symptoms. If lung cancer or a cancer of the air passages is present, the person may cough up blood. Other signs and symptoms that may warn of a cancer include worsening fatigue, loss of appetite, unexplained loss of weight, or decreased ability to swallow solid or liquid foods.

Causes of cough:

The causes of chronic cough can be divided based on their locations with respect to the lungs.

The categories of causes of cough are:

·         Environmental irritants - Cigarette smoke, dust, pollens, pet dander, certain fragrances or industrial chemicals and pollution, and low environmental humidity.

·         Conditions within the lungs - asthma, emphysema (lung disease causing shortness of breath), and chronic bronchitis. Less common causes of lung-induced chronic cough include cancer, sarcoidosis (abnormal collection of inflammatory cells in lungs), diseases of the lung tissue, and congestive heart failure with chronic fluid build-up in the lungs.

·         Conditions along the air passages that carry air from the lungs to the environment

·         Chronic sinus infections and chronic postnasal drip

·         Conditions within the chest but outside of the lungs - diseases of the external ear and infections of the throat.

·         Diseases elsewhere within the chest cavity may also be responsible for chronic cough. Conditions within the chest known to cause chronic cough include cancer, unusual growth of a lymph node, and an abnormal enlargement of the aorta, the main blood vessel leaving the heart.

·         Use of heart care medications like ACE inhibitors.

·         GERD (acidity problem) is the most over-looked cause of the chronic cough. This abnormal condition can cause irritation of the esophagus (passage from where air/food passes down in stomach) and larynx resulting in the reflex production of a cough.

Diagnosis/Tests:

Accurate diagnosis of cough can be done based on the medical history of the patient along with other related information like the duration of the cough, associated signs and symptoms, irritant agent or locations that make the cough worse or better, relation between the cough and time of day, any home remedies, if at all.

Various tests examinations that may throw light on the cause of cough and help diagnose the underlying condition include Chest X-ray, Examination of oropharynx, Auscultation of the chest, Chest radiography, Pulmonary function testing, Measurement of forced expiratory flow rates, Gross &  microscopic examination of sputum.

Other specialized testing which may be advised by the physician depending on the seriousness of the condition include Fiberoptic bronchoscopy, High-resolution computed tomography (HRCT).

Children with TB risk factors or weight loss should have a chest x-ray for TB while children with repeated episodes of pneumonia, poor growth, or foul-smelling stools should have a chest x-ray and sweat testing for cystic fibrosis (disease where sticky mucus builds up in lungs & other organs).