The right treatment can conquer chronic cough

By Jennifer Laliberté

Medically speaking, coughing is a pretty banal thing. But with cold and flu season upon us there's nothing trivial about the scores of nasty coughing fits that you'll be seeing. Most patients just need to let things run their course, but persistent hackers need more than just a few days of bed rest.

A chronic cough is one that lasts more than eight weeks. And unfortunately, over-the-counter (OTC) cough suppressants won't do any good in these cases, according to treatment guidelines published by the American College of Chest Physicians (ACCP). "Most over-the-counter cough expectorants or suppressants, including cough syrups and cough drops, do not treat the underlying cause of the cough," says Dr Louis-Philippe Boulet, a respirologist from Quebec City who contributed to the guidelines. But there are things that do work — the key is finding the right one.

SMOKE AND MIRRORS
The first thing that comes to mind when a patient just can't shake a cough is, of course, smoking. "It's a real problem," says Dr Robin McFadden, chief of respirology at St Joseph's Healthcare London. "The most common cause of cough is a simple respiratory tract infection, but if the patient smokes, that cough just goes on and on." The first order of business is to recommend they give up the habit and, more often than not, the cough will resolve. But it's also important to make sure patients understand you're not dismissing or punishing them. "You have to explain that it's difficult to really get to the bottom of what's causing the cough if they smoke," he says. "Once we've ruled out the serious things, there's really just not much else we can do."

You should also ask patients if they're taking an angiotensin converting enzyme inhibitor (ACEI) to lower their blood pressure — chronic cough is a common side effect. "Before undergoing various investigations, ACEIs should be discontinued, regardless of the temporal relation between the onset of cough and the initiation of ACEI therapy," says Dr Boulet. Be sure to tell your patients that it could take as long as three months for the cough to resolve once they stop taking the medication. Most, though, will see a marked improvement in a few weeks.

TRIAL AND ERROR
Other than smoking and ACEIs, the four most common causes of chronic cough are upper airway cough syndrome (UACS, commonly known as postnasal drip), asthma, non-asthmatic eosinophilic bronchitis (NAEB) and gastroesophageal reflux disease (GERD), in that order. A careful history can help point you in the right direction, but you can never really be sure you're on the right track until a successful course of treatment confirms the diagnosis (See "Treatment by trial: common causes of chronic cough," above). "It's important to tell patients from the get-go that they may have to come back several times," says Dr McFadden.

Ask patients when the cough tends to be worse: certain times of day, seasons or in response to certain exposures, he suggests. A cough that's most bothersome first thing in the morning is more likely to be caused by UACS, for example, while one that's brought on by cold air or strong fumes suggests twitchy airways and possible asthma. But the nature of the cough itself — wet or dry, superficial or guttural — isn't very useful in making a diagnosis, warns Dr Boulet. "The character of the cough may be misleading," he says.

As far as ordering a chest x-ray goes, it's up to your good judgement. Don't let patients pressure you into it; tell them that it's a relatively low-yield test, meant only to capture big scary things like lung cancer. "If you get an x-ray of everyone that comes in with a cough, you're going to find all sorts of insignificant, minor abnormalities that will require more work-up. You'll just freak people out for no reason," says Dr McFadden.

If you've exhausted all the common avenues and nothing seems to help, a chest CT or a bronchoscopic examination may be warranted. "Some form of allergy assessment is also worthwhile. You may get some surprises," adds Dr McFadden. Sometimes though, your best bet may be to let things go for a while. "There comes a point where I tell them they can't let this rule their life," Dr McFadden says. "They know that they can come see me if things change, but we don't always have all the answers."