PURPOSE: To evaluate the outcome of diagnostic work-up of patients referred for subacute or chronic cough with no suggestive diagnostic clues.
METHODS: Prospective study of patients referred to the pulmonary clinic with the following inclusion criteria: 1)cough > 3 weeks 2)normal chest radiograph 3)non smoker 4)no use of Angiotensin Converting Enzyme inhibitors (ACEI) 5)Absence of suggestive symptoms of asthma (wheeze, dyspnea) OR upper airway cough syndrome (rhinorrhea,’blocked’ nose, post nasal dripping, throat itchiness) OR gastroesophageal reflux disease[GERD](epigastric burning, acid regurgitation, frequent belching) 6)Normal physical examination findings. All patients were sent for methacholine challenge testing (MCT). We followed up these patients and classified the final diagnoses into 3 categories; a)Likely (some objective evidence such as positive MCT or findings on nasal endoscopy) b)Possible(response to a therapeutic trial or diagnostic clues in the history) c)No diagnosis established.
RESULTS: Forty five patients met the study criteria (26 males and 19 females) with ages ranging from 18 to 73 years (median 40 yrs). The duration of cough ranged from 3 weeks to 5 years (median 12 weeks). All patients had negative MCT results. A likely diagnosis was obtained in 18 patients (GERD 7, allergic rhinitis 11, sinusitis 2, vocal cord nodule 1). There was a dual pathology reported in 3 patients. A possible diagnosis was achieved in 14 patients (GERD 9, allergic rhinitis 2, psychogenic cough 1, morbid obesity 1, post viral 1). No diagnosis could be made in 14 patients. The cough improved in 39 patients, but persisted in 5 patients (one defaulted follow-up).
CONCLUSION: We were able to achieve a diagnosis in 31 patients (68%). GERD(16 patients) and allergic rhinitis(13 patients)were the most common causes. Bronchial asthma was not identified as a cause in any of our patients.Improvement of symptoms were seen in 39 patients(86%).
CLINICAL IMPLICATIONS: Subacute or chronic cough can be a difficult diagnostic problem when unaccompanied by suggestive diagnostic clues. One third of patients in our study did not have a diagnosis established. However, resolution of cough was seen in the vast majority.
DISCLOSURE: Vijo Poulose, None.