Prolonged cough presenting with diagnostic difficulty: a study of aetiological and clinical outcomes

Prolonged cough is a common reason for referral to a respiratory physician. Some cases of prolonged cough can be a diagnostic challenge, especially when it is not accompanied by features that suggest common aetiologies. The current study examined this group of patients so as to ascertain the final aetiological and clinical outcomes.

We performed a chart review of cases that had been prospectively identified. The inclusion criteria were cough lasting more than three weeks, normal chest radiograph, non-smoking status, no history of angiotensin-converting enzyme inhibitor use, normal physical examination and absence of suggestive features of asthma, gastroesophageal reflux disease and postnasal drip syndrome. We classified the final diagnoses into three categories: likely diagnosis; possible diagnosis; and no diagnosis established, and traced the clinical outcomes.

A total of 54 patients met the study criteria. The median duration of cough was 16 weeks (range four weeks to five years), while the median age of the patients was 38 (range 18-73) years. A likely diagnosis was reached in 23 patients and a possible diagnosis, in 12 patients. Gastroesophageal reflux disease and postnasal drip syndrome were the commonest diagnoses. There were no cases of asthma. The cough improved completely in 44 patients. Three cases were lost to follow-up before an outcome could be documented.

In most of these cases, a diagnosis could be achieved. The cough improved in the majority of patients, including those in whom a diagnosis could not be made.