Lingering postinfectious cough has been a concern across Canada this winter. , according to an overview published on February 12 in the Canadian Medical Association Journal
“It’s something a lot of patients are worried about: That lingering cough after a common cold or flu,” lead author Kevin Liang, MD, of the Department of Family Medicine at The University of British Columbia in Vancouver, British Columbia, Canada, told this news organization. He added that some studies show that as much as a quarter of adult patients have this complaint.
Dr. Liang and his colleagues emphasized that the diagnosis of postinfectious cough is one of exclusion. It relies on the absence of concerning physical examination findings and other “subacute cough mimics” such as asthma, chronic obstructive pulmonary disease (COPD), gastroesophageal reflux disease, or use of angiotensin-converting enzyme inhibitors.
“Pertussis should be considered in patients with a paroxysmal cough, post-tussive vomiting, and inspiratory whoop,” they added. Coughs that persist beyond 8 weeks warrant further workup such as a pulmonary function test to rule out asthma or COPD. Coughs accompanied by hemoptysis, systemic symptoms, dysphagia, excessive dyspnea, or hoarseness also warrant further workup, they added. And patients with a history of smoking or recurrent pneumonia should be followed more closely.
In the absence of red flags, Dr. Liang and coauthors advised that there is no evidence supporting pharmacologic treatment, “which is associated with harms,” such as medication adverse effects, cost, strain on the medical supply chain, and the fact that pressurized metered-dose inhalers emit powerful greenhouse gases. “A lot of patients come in looking for solutions, but really, all the evidence says the over-the-counter cough syrup just doesn’t work. Or I see clinicians prescribing inhalers or different medication that can cost hundreds of dollars, and their efficacy, at least from the literature, shows that there’s really no improvement. Time and patience are the two keys to solving this,” Dr. Liang told this news organization.
Moreover, there is a distinct absence of guidelines on this topic. The College of Family Physicians of Canada’s recent literature review cited limited data supporting a trial of inhaled corticosteroids, a bronchodilator such as ipratropium-salbutamol, or an intranasal steroid if postnasal drip is suspected. However, “there’s a high risk of bias in the study they cite from using the short-acting bronchodilators, and what it ultimately says is that in most cases, this is self-resolving by around the 20-day mark,” said Dr. Liang. “Our advice is just to err on the side of caution and just provide that information piece to the patient.”
‘Significant Nuance’
Imran Satia, MD, assistant professor of respirology at McMaster University in Hamilton, Ontario, Canada, agreed that “most people who get a viral or bacterial upper or lower respiratory tract infection will get better with time, and there is very little evidence that giving steroids, antibiotics, or cough suppressants is better than waiting it out.” There is “significant nuance” in how to manage this situation, however.
“In some patients with underlying lung disease like asthma or COPD, increasing the frequency of regular inhaled steroids, bronchodilators, oral steroids, antibiotics, and chest imaging with breathing tests may be clinically warranted, and many physicians will do this,” he told this news organization. “In some patients with refractory chronic cough, there is no underlying identifiable disease, despite completing the necessary investigations. Or coughing persists despite trials of treatment for lung diseases, nasal diseases, and stomach reflux disease. This is commonly described as cough hypersensitivity syndrome, for which therapies targeting the neuronal pathways that control coughing are needed.”
Physicians should occasionally consider trying a temporary course of a short-acting bronchodilator inhaler, said Nicholas Vozoris, MD, assistant professor and clinician investigator in respirology at the University of Toronto, Toronto, Ontario, Canada. “I think that would be a reasonable first step in a case of really bad postinfectious cough,” he told this news organization. “But in general, drug treatments are not indicated.”