Cough

Coughs Overview

A cough is an action your body takes to get rid of substances that are irritating to your air passages, which carry the air you breathe in from the nose and mouth to the lungs. A cough occurs when special cells along the air passages get irritated and trigger a chain of events. The result? Air in your lungs is forced out under high pressure. You can choose to cough (a voluntary process), or your body may cough on its own (an involuntary process).

Causes of Coughs

The list of possible causes of cough is long and highly varied. Doctors classify coughs into 2 categories, acute and chronic. Many doctors define an acute cough as one that been present for less than 3 weeks. Chronic coughs are those present for more than 3 weeks.

* Acute coughs can be divided into infectious (caused by an infection) and noninfectious causes.

* Infectious causes of acute cough include viral upper respiratory infections (the common cold), sinus infections, pneumonia, and whooping cough.

* Noninfectious causes of cough include flare-ups of the following chronic conditions: chronic bronchitis, emphysema, asthma, and environmental allergies.

* The easiest way to simplify the causes of chronic cough is to divide them into their locations with respect to the lungs. The categories are environmental irritants, conditions within the lungs, conditions along the passages that transmit air from the lungs to the environment, conditions within the chest cavity but outside of the lungs, and digestive causes.

* Any environmental substance that irritates the air passages or the lungs is capable of producing a chronic cough with continued exposure. Cigarette smoke is the most common cause of chronic cough. Other cough-producing irritants include dusts, pollens, pet dander, particulate matter, industrial chemicals and pollution, cigar and pipe smoke, and low environmental humidity.

* Within the lungs both common and uncommon conditions cause chronic cough. Common causes include asthma, emphysema, and chronic bronchitis. Less common causes of lung-induced chronic cough include cancer, sarcoidosis, diseases of the lung tissue, and congestive heart failure with chronic fluid build-up in the lungs.

* The passages that connect the lungs to the external environment are known as the upper respiratory tract. Chronic sinus infections, chronic postnasal drip, diseases of the external ear, infections of the throat, and use of ACE inhibitors for high blood pressure have all been implicated in chronic cough.

* In addition to disease processes within the lung and air passages, 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, which is the main blood vessel leaving the heart.

* An often-overlooked cause of the chronic cough is gastroesophageal reflux (GERD). GERD occurs when acid from the stomach travels up the esophagus. This abnormal condition can cause irritation of the esophagus and larynx resulting in the reflex production of a cough.

Cough Symptoms

Although the signs of a cough are self-explanatory, what differentiates the cause of a cough are the associated signs and symptoms. Another important factor in determining the cause of the cough is whether it is acute or chronic.

* Acute coughs have been divided into infectious and noninfectious causes.

o Signs and symptoms that point to an infection include fever, chills, body aches, sore throat, nausea, vomiting, headache, sinus pressure, runny nose, night sweats, and postnasal drip. Sputum, or phlegm, sometimes indicates an infection is present, but it is also seen in noninfectious causes.

o Signs and symptoms that point to a noninfectious cause include coughs that occur when you are exposed to certain chemicals or irritants in the environment, coughs with wheezing, coughs that routinely worsen when you go to certain locations or do certain activities, or coughs that improve with inhalers or allergy medications.

* The signs and symptoms of the chronic cough can be hard for doctors to assess, because many causes of the chronic cough have overlapping signs and symptoms.

o If your cough is related to environmental irritants, it will worsen when exposed to the offending agent. If you have an environmental allergy, your cough may improve when using allergy medications. If you have a smoker's cough, it may improve if you stop smoking and worsen with increased smoking.

o If you have a chronic lung disease such as asthma, emphysema, or chronic bronchitis, you may have a persistent cough or a cough that worsens with certain locations or activities. You may or may not have sputum with your cough and often have improvement in your cough with the use of inhaled or oral steroids, or other inhaled medications.

o If your cough is caused by chronic sinus infections, chronic runny nose, or chronic postnasal drip, you will often have the signs and symptoms associated with these conditions. You may also notice that your cough worsens when your problem worsens, and often your cough will improve when the underlying problem is treated.

o If your cough is associated with medications, such as angiotensin converting enzyme (ACE) inhibitors, the cough will begin after starting the medication in question. The cough is often dry and improves when the medication is stopped.

o A cough associated with GERD is often associated with a sensation of heartburn. This type of cough worsens during the day or when you lie flat on your back. Furthermore, a sizable minority of people with a cough caused by GERD will note no symptoms of reflux, but most people will report improvement in their cough when GERD is treated properly.

o If your cough is a warning sign of an underlying cancer, you may have a group of symptoms. If lung cancer or a cancer of the air passages is present, you 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.
by:http://www.emedicinehealth.com/