Causes of Chronic Coughing

Aside from fatigue and chest pain, coughing is an indicator of a respiratory malady as it is the most common symptom when the body tries to get rid of foreign particles that may be harmful to our respiratory system, including viruses – such as Tuberculosis (TB).  Though coughing helps expel viruses from our body, it actually spreads the viruses to others also. 

Breathing

The human’s respiratory system has 2 functions: bringing in oxygen to nurture the body, and excreting waste which is carbon dioxide as a result of our metabolism (e.g., digesting sugar, etc.) that generates energy for the body.   If the lungs are not functioning properly, the human body may not be able to survive as it does not receive sufficient amount of oxygen to maintain the pH balance from carbon dioxide deposit in the blood stream.   

In general, there are 2 parts of respiratory system:

1. Upper Respiratory Tract that includes the nose or nostrils, nasal cavity, mouth, throat (pharynx), and voice box (larynx).
2. Lower Respiratory Tract which is below the larynx, stretching from the windpipe (trachea) to alveoli.

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Coughing

Coughing is one of the mechanisms to protect the respiratory system from harm.  Normally, we inhale a lot of air into our lungs daily (approximately 8,000-12,000 liters per day, depending on the amount of work and exercises).  The air that we breathe in, especially in big cities, somehow contains pollution from cigarettes smoke and other particles – such as chemical fumes, diseases, bacteria and viruses.  So, our body needs a way to excrete them.  Any particle that is larger than 10 microns will be stuck in our nostril and upper trachea, while anything smaller will pass through to our lower part.  Thus, the small particles are more harmful than larger ones.

The tissue lining the trachea has small, hair-like structures that are covered with mucous sheet or mucociliary blanket which moves constantly to push mucus out of the trachea; so that we either cough it out or swallow it into our stomach.  Any foreign particle inhaled into the trachea will be caught by the mucous sheet.  Harmful chemicals are thus trapped and diluted, making them less toxic.  Gases are similarly handled.  Bacteria and viruses, too, are rendered harmless by the antibodies within the mucous sheet and by the body’s white blood cells, before they are discarded as phlegm.   Normally, we excrete very little of the mucus – about 10 to 100 cubic cm. daily – such that we do not notice it much, as it is usually swallowed with our saliva.

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Duration of Coughing

Coughing duration can be classified as follow:

• Acute coughing – less than 1 week
• Chronic coughing – over 3 weeks
• Dry coughs with or without phlegm. It is necessary to check also whether or not there is blood mixed together with the phlegm.

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Causes of Acute Coughing

Almost all of the respiratory and lung diseases can cause coughing.  However, there are other diseases or maladies that can also cause coughing – such as nose disorders, gastritis, and heart disease.  In addition, there are many kinds of medicines that can cause coughing as well.  Normally, acute coughing is caused by inflamed upper respiratory tract from an infection such as a cold or influenza.  In children, it can be a throat inflammation or tonsillitis.  For older adults, especially those who suffer from some types of brain disorder, coughing may be brought on by bronchitis from regurgitation of food or saliva.

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Causes of Chronic Coughing

Aside from chronic bronchitis in smokers, post-viral coughing from a cold or influenza is common among those who do not have enough rest and use their voice excessively during the on-set of the sickness.  If this is the case, they may be affected by Bronchial Hyperresponsiveness (BHR) for another 3-4 weeks; especially if they continue use their voice a lot and without sufficient rest.    

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Diseases that Cause Coughing

Chronic inflammation in the lungs such as TB, bronchiectasis, abscess in the lungs and lung cancer can also cause coughing.  Chest x-ray can help diagnose these diseases.  

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Other Chronic Coughing even with Clear Chest X-ray

• Bronchial Asthma often comes with coughing, shortness of breath, and wheezing.  There are many patients with minor bronchitis who may never have asthma attack or shortness of breath but only chronic coughing (25% of the patients never experience such symptoms). However, pulmonary function test can detect BHR condition.  Moreover, patients who have chronic bronchitis will have Eosinophils in their phlegm rather than Neutrophils which is common among general bronchitis. Eosinophilic Bronchitis is also known as Cough-Variant Asthma which is asymptomatic bronchitis with mild bronchial stenosis.
• Allergic Rhinitis is an allergic reaction that causes stuffy and runny nose with postnasal drip, causing chronic coughing.  Patients may also have paranasal sinusitis, and so it is often associated with asthma. 
• Gastro-Esophageal Reflux Disease (GERD) can cause chronic coughing as well.  Normally, in the upper gastrointestinal tract, food passes through the mouth, throat, and esophagus before getting to the stomach.  There is a gastroesophageal sphincter or lower esophagus sphincter that prevents food and acid from a reflux.  
• Medication for Hypertension and Heart Diseases such as ACE Inhibitor may cause chronic coughing.  Approximately 2-14% of patients will experience the symptom within 3-4 weeks after commencing the medication.  This type of coughing is without phlegm and happens at night when you lie down on your back.  The symptoms will disappear after you stop the medication.  Furthermore, Beta-Adrenergic Blocking Agent may also cause coughing from bronchial stenosis in patients with chronic bronchitis and asthma.
• Excessive Use of Voice such as among traders who have to turn up their voices at work and do not have enough rest.  They will feel better after a few days’ rest.
• Psychogenic or Habit Cough is a repetitive coughing that occurs in the absence of any underlying disease.  It is considered to have a psychiatric or psychological basis.

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Effects of Coughing 

• Brain

• • Cough Syncope

• Chest

• • Sore or torn muscles, broken ribs

• Other Complications 

• • Urine incontinence
  • Hoarse voice
  • Hernia
  • Back pain
  • Sleeplessness for patients who have symptoms at night 

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Diagnosis for Coughing

Generally, the doctor will check your health history and order a physical examination as well as a chest x-ray to determine the cause of your coughs.  In some cases, there may be additional tests for even more accurate diagnosis of up to 90%.  Although the causes are mainly from pulmonary and respiratory system diseases, it can also be from heart or gastrointestinal tract diseases.  Moreover, approximately 20-60% of the coughs may not come from just one disease.  Other causes include:

• In the case of suspected lung disease – the doctor may order an additional chest x-ray.
• In the case of suspected nose and trachea infections – this may involve an ear-nose-throat specialist who will help further diagnose the ailment by ordering additional sinus x-ray (cavity near nasal passage).
• In the case of suspected bronchitis – the doctor will order a pulmonary function test to see if there is any bronchial stenosis. If so, the patient will be treated with a nebulizer to open the air passageway.  If the patient responds well to the treatment, it indicates greater accuracy to the diagnosis. Often, though, some asthmatic conditions are asymptomatic and the sickness cannot be properly determined, as the initial functional test may not reveal any problem. So, the doctor will order a Bronchial Challenge Test that uses an agitating agent to induce narrowing of the air passageway.  This test requires a high accuracy equipment known as Body Plethysmography through which other lungs’ capabilities – such as lungs capacity, and gas exchange ability of the alveoli – can be determined.  The regular Spirometer equipment does not have these proficiencies.
• In the case of suspected GERD – the doctor will order gastrointestinal test as indicated previously.  This test will help diagnose and treat the problem with up to 90-95% accuracy. 

Many diseases, if left untreated for a long time, may be too difficult to treat or become incurable.  Patients who have chronic coughing should not ignore such a condition for too long.