The symptom of a cough is a common reason for seeking medical attention.
A cough can be the first sign of a serious underlying medical condition. When it lasts more than 3 weeks, it needs to be evaluated by a physician. By itself, a cough causes discomfort, headaches, dizziness, rib fractures, can push away friends and family, interfere with work and play, interrupt sleep, and cause frustration and anger.
What is a cough?
Everyone knows a cough when you hear it. But what causes it and why do we do it?
A cough is a normal reflex that protects our lungs and airway. A cough clears mucus, bacteria, foreign bodies and irritants such as smoke or stomach acid in patients with gastroesophageal reflux disease (GERD). The cough helps to prevent infections. A cough is a necessary part of everyday life.
Coughing occurs when the nerve endings that line the airway are irritated. The nerve endings of the airway do not sense pain, but do trigger the cough reflex. Direct physical contact with irritants, exposure to allergens, taking certain medicines, will irritate the nerves in the airway. This stimulates the cough center in the area of the brain known as the medulla.
The medulla coordinates a rapid, complex series of actions. The muscles of respiration, including the chest wall muscles and the diaphragm, contract to draw air into the lungs. Then the upper airway including the vocal cords close. Suddenly, the respiratory muscles reverse and the muscles of the abdominal wall assist in building up pressure in the air trapped in the lung. The vocal cords open and the trapped, high pressure air rushes out of the airway rapidly, resulting in a cough.
Not all coughing is normal or helpful. A cough that occurs over a prolonged period of time can become a significant problem. It can cause chest pain. It can cause someone to pass out. It can cause urinary incontinence. A cough can wake a person from sleep and severely interrupt sleep and lead to exhaustion. A person suffering from a chronic cough can have significant interference in their social and work life.
In some people with impaired nervous systems or impaired musculature, a cough reflex may be limited or absent. The ability to clear the airway can lead to infections such as pneumonia or bronchitis.
Diagnosing and Treating the Cough
A cough is the reaction to an irritation to the respiratory tract.
Common irritants, including infections, stomach acid, mucus, allergic inflammation, smoke, perfumes and air pollution. The cough is initially classified by its duration. An acute cough lasts less than 3 weeks and typically is caused by an infection in the airway. A chronic cough lasts longer than 3 weeks and has multiple potential causes that require medical evaluation and treatment.
When a physician, typically a pulmonologist or an allergist, evaluates a patient for a chronic cough, the initial thought is: Stop Smoking! This is the first step in the work-up of a chronic cough (and any other disease!).
If the patient is a nonsmoker, the pulmonologist looks for signs or symptoms related to the three most common causes of a chronic cough: post-nasal drip, reflux disease (heartburn), and asthma.
An assessment of the person's medical history, medication usage, allergies, nasal symptoms, post-nasal drip, heartburn, a sour taste in the mouth, wheezing, chest tightness and shortness of breath will be made.
Certain commonly used medicines can cause a chronic cough. A category of blood pressure medicine known as the ACE-inhibitors are the most commonly associated medicine with a chronic cough. The risks and benefits of the therapy need to be assessed prior to stopping or changing the medicine.
Further testing and therapy is then started to address the cough:
- A chest X-ray is usually considered if there is no clear diagnosis based on the patient’s history.
- CT scans of the lungs and sinuses can help evaluate underlying diseases.
- Allergen skin testing can help evaluate if there are environmental allergens that may contribute to the cough.
- Occasionally, a test of the presence of stomach acid in the esophagus, known as a pH probe, is performed.
When there is a chronic cough, a thorough evaluation by a specialist is necessary.
The Pulmonologists and Allergists of the Respiratory Specialists are experts in diagnosing and treating chronic cough.