With persistent cough, a search for underlying cause is key

DEAR DR. ROACH

» Cough seems to be going around here in the Northwest. My wife has coughed excessively for months now. She was given hydrocodone-homatropine syrup for a month, but the doctor won’t re-prescribe it. So now my wife takes many OTC cough syrups and suppressants, plus nighttime cold formulas. None of them does anything, and she continues to cough, losing sleep and feeling worn out all day. She takes allergy meds also. What can be done? — J.A.C.

DEAR READER » Cough is a symptom of several possible conditions. When people have a cough for a few days, usually it is due to an infection. Typically this is a viral upper-respiratory infection. Sometimes it is bacterial or, more concerning, pneumonia (which is a lower-respiratory infection, but it’s almost never called that).

Cough that has gone on for months should make her doctor consider other possibilities. Instead of treating the symptom (cough), the doctor should be looking for the underlying cause. This is better than represcribing powerful cough suppressants.

The common causes of chronic cough depend on the person. If your wife were a smoker, then chronic bronchitis — a type of chronic obstructive pulmonary disease — would be most likely. If she were taking a type of blood pressure medication called an ACE inhibitor, such as lisinopril, that would be a likely culprit. In someone with no particular risks, I think first about gastroesophageal reflux disease, asthma and postnasal drip.

GERD usually shows up as heartburn. Many people have no stomach complaints but do have a cough (the vagus nerve is involved with both the cough reflex and the nerve supply to the stomach and esophagus). Physicians first will try a powerful antacid medication, such as omeprazole, as a diagnostic test. If the medicine stops the cough, it’s suggestive that the cause of the cough was GERD. Other times, an endoscopy or direct pH monitoring of the esophagus will make the diagnosis.

Similarly, asthma usually has wheezing, but cough-variant asthma is not at all uncommon. Again, a doctor might have her try an inhaler as a diagnostic test. Formal pulmonary function testing is the definitive way to make the diagnosis of asthma, but the doctor may need to include a trial of methacholine, a substance that can trigger asthma symptoms in people so disposed.

Since your wife seems to have allergies, postnasal drip is a likely cause, and a careful exam sometimes will show it. An ENT doctor can look endoscopically, or a different kind of medication (I often try nasal steroids) might help.

These are not the only causes. There are lung conditions, including unusual chronic infections (tuberculosis, M. avium and others) and even lung tumors, that should be evaluated by X-ray or even CT scan in the right circumstances.

Keith Roach To Your Good Health