Is there a role for bronchoscopy in the workup of cough?

When should bronchoscopy be performed in the evaluation of cough?

• The evaluation of cough remains an important clinical problem for primary care physicians and pulmonologists alike. In the past 5 years, the American College of Chest Physicians,¹ the British Thoracic Society,² and the European Respiratory Society³ have published comprehensive guidelines to assist in standardizing the approach to cough evaluation. While determining the cause of cough can be vexing initially, prospective studies have shown that the cause can be established in more than 90% of patients.

The consensus definition of chronic cough is a cough of 8 weeks' duration or more. The most common causes of chronic cough include upper airway cough syndrome with postnasal drip, asthma, eosinophilic bronchitis, gastroesophageal reflux disease (GERD), and chronic bronchitis; these conditions constitute approximately 95% of all causes. Given these diagnoses, it is therefore not surprising that the utility of bronchoscopy in the evaluation of chronic cough is minimal.

The 2 major indications for bronchoscopy in the evaluation of cough are hemoptysis and suspicion of foreign-body aspiration. Bronchoscopy should be considered in the evaluation of these conditions regardless of the duration of cough. Interestingly, patients with hemoptysis or suspected foreign-body aspiration are usually excluded from bronchoscopy studies that target cough. For example,Barnes and colleagues⁴ evaluated the utility of bronchoscopy among 48 highly selected patients referred to the Mayo Clinic for cough over a 5-year period. The patients were excluded from the analysis if they had evidence of hemoptysis, bronchiectasis, broncholithiasis, atelectasis, or adenopathy.

All of the patients in this study were first tested for GERD, asthma, and rhinitis, and 21 of the 48 patients had undergone CT of the chest.⁴ Thirty-seven of the patients had "normal" findings at bronchoscopy, and the most common abnormal finding was bronchitis in 9 patients. No endobronchial malignancies were found, and the authors suggested that bronchoscopy adds little to the evaluation of chronic cough.

In our tertiary referral practice, we consider bronchoscopy to be useful in a few specific patients with chronic cough. Patients who have evidence of bronchiectasis and small nodular changes on high resolution CT scans may undergo bronchoscopy to evaluate for evidence of mycobacterial infection, but only if they are unable to produce induced-sputum samples.

Likewise, patients with early findings of interstitial lung disease on a chest radiograph or CT scan may be referred for bronchoscopy with transbronchial biopsy sampling if sarcoidosis, infection, or malignancy is suspected. In addition, patients who have known granulomatous disease and evidence of calcified nodes abutting the airways on a CT scan may undergo bronchoscopy to evaluate for a broncholith eroding into the major airways.

While these are a few specific examples of conditions that can cause chronic cough and can be diagnosed by bronchoscopy, we emphasize that bronchoscopy would generally be considered only after an exhaustive search for other causes has been done.

In summary, bronchoscopy should be considered in patients who present with cough if the history includes evidence of hemoptysis or suggests foreign-body aspiration. In other instances, bronchoscopy will rarely aid in the diagnosis of cough and should be considered a lesser priority. The decision to pursue bronchoscopy in the evaluation of chronic cough is situational and should be made in consultation with a cough specialist. Overall, the systematic evaluation of cough can lead to a diagnosis in more than 90% of patients. Recent guidelines can help us in the evaluation of this common problem.

References:

REFERENCES

1.

Pratter MR, Brightling CE, Boulet LP, Irwin RS. An empiric integrative approach to the management of cough: ACCP evidence-based clinical practice guidelines.

Chest.

2006;129(suppl 1):222S-231S.

2.

Morice AH, McGarvey L, Pavord I; British Thoracic Society Cough Guideline Group. Recommendations for the management of cough in adults.

Thorax.

2006;61(suppl 1):1-24.

3.

Morice AH, Fontana GA, Sovijarvi AR, et al. The diagnosis and management of chronic cough.

Eur Respir J.

2004;24:481-492.

4.

Barnes TW, Afessa B, Swanson KL, Lim KG. The clinical utility of flexible bronchoscopy in the evaluation of cough.

Chest.

2004;126:268-272.