If you come down with a common viral respiratory infection, any cough associated with it usually goes away in a week or two. No big deal.
But a cough that doesn’t go away is something else, and it can be a very big deal.
The most common reason a cough persists for more than two weeks is because the person with the cough is a smoker. Smoking damages the lungs’ bronchial tubes and makes them less able to quickly fight off an acquired infection.
A person who smokes has reason to worry about a persistent cough, especially if it’s not associated with sinus symptoms typical of a common viral infection.
The initial symptom of a lung cancer is often a cough. A cough that produces sputum specked or streaked with blood demands a visit to a physician.
Sinuses and asthma
Chronic sinusitis is one of the most common causes of a continuing cough in older adults.
Secretions produced by the inflamed sinus membranes drain down the back of the throat and enter the passage to the lungs.
The resulting irritation of the bronchial tubes leads to the typical irritative cough. The cough is usually dry, but secretions may be brought up after awakening in the morning. It abates only after successful treatment of the sinus condition.
A persistent cough is sometimes present in those with allergic or perennial asthma. An asthmatic cough may be more troublesome for a person than shortness of breath or wheezing, and it may be the first symptom of the ailment.
And yes, asthma can come on at any age.
Regurgitation of stomach fluids during sleep can be the cause of a cough that won’t go away.
If the valve at the top of the stomach doesn’t function properly, stomach contractions can propel acidic secretions up the esophagus (swallowing tube).
Bronchitis and cough develop when this fluid overflows into the airway tubes.
The reflux of stomach contents into the esophagus often occurs silently at night when the sleeping position has eliminated the defense of gravity. If a correct diagnosis is made, treatment is highly effective.
A cough can also be the result of swallowed food or fluid “going down the wrong pipe.” If this occurs on a regular basis, the cough will persist.
Aspiration of swallowed food or fluid into the lung is unusual in healthy persons, but is common among the chronically ill and in those who are bedridden.
Persons with impairment of the swallowing mechanism, such as those with strokes, Parkinson’s disease or advanced Alzheimer’s disease, are most susceptible.
An annoying and persistent dry cough is a potential side effect of a class of drugs called ACE inhibitors (for example, lisinopril, Prinivil and Accupril). These agents are commonly prescribed by physicians to treat hypertension, heart and kidney disease.
About 10 percent of users develop the cough. It’s a dry, non-congested nuisance cough that resolves when the medication is stopped.
Some people cough for the same reason they bite their fingernails: It’s a habit. A habitual cough isn’t present during sleep.
Other causes of a persistent cough include heart failure, an enlarged thyroid gland, tuberculosis, bronchial damage from previous pneumonia and rare ailments that cause formation of scar tissue in the lungs.
Sometimes the best of doctors may not find a cause and reluctantly attribute the cough to simple degeneration of airway tissues.
Anyone suffering from a persistent cough should see a physician. The medical history and physical examination often are sufficient to lead to the correct diagnosis, but a chest X-ray, a CT scan of the chest or a referral to a chest specialist may be needed.
Dr. Michael Spilane, now retired, spent more than four decades practicing and teaching geriatric medicine in St. Paul. Send comments or questions to firstname.lastname@example.org.