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A3195 - Using Bronchial Biopsies and Cultures to Improve the Diagnostic Yield of Bronchoscopy for Chronic Unexplained Cough
Author Block: M. Heching, B. Pertzov, D. Rosengarten, A. Unterman, M. R. Kramer; Rabin Medical Center, Petach Tikva, Israel.
RATIONALE Prior studies assessing the diagnostic utility of bronchoscopy to identify the etiology of chronic unexplained cough have achieved modest yields. Such relatively limited results may relate to the utilization of bronchoscopy chiefly to identify endobronchial anatomical abnormalities likely contributing to the chronic cough. Based on our institutional experience, we believe that expanding bronchoscopy beyond visualization alone to include bronchial washings and endobronchial biopsies can meaningfully increase the diagnostic yield for identifying the etiology of chronic cough. METHODS We conducted a retrospective review of all bronchoscopies conducted in our institution from 1/2013 through 9/2017. Eligibility criteria were bronchoscopies for the primary indication of chronic unexplained cough for which no etiology had been previously identified. For each patient, we reviewed prior evaluations and treatments targeted at identifying the etiology and relieving the chronic cough. We then analyzed the anatomical findings on bronchoscopy as well as the results of microbiology, pathology and cytology testing from the bronchoscopy in an effort to identify the yet undiscovered etiology of the chronic cough. RESULTS Over the study period, 171 bronchoscopies met the eligibility criteria. Patient average age was 60 years and 61% were female. Biopsies were collected for 92% of the bronchoscopies, cytology for 98% and all procedures included bronchial washings for cultures. Direct visualization of the airways identified 44 (26% of total bronchoscopies) anatomical anomalies believed to be the proximal cause of chronic cough, most commonly tracheobronchmalacia and polyps in the trachea or larynx, as well as less common conditions such as tracheobronchopathia osteochondroplastica and amyloidosis. Cultures were positive for 36 (21% of bronchoscopies) microbes representing clear etiology of the patient’s cough, most commonly Pseudomonas aeruginosa, non-tuberculosis mycobacterium, Staphylococcus aureus and Streptococcus pneumoniae, as well as an additional 19 (11% of bronchoscopies) microbes representing a potential etiology for chronic cough, principally Haemophilus influenza and Moraxella catarrhalis. Pathology results from endobronchial biopsies resulted in an additional 18 (10% of bronchoscopies) identified respiratory conditions associated with cough, most prominently eosinophilic bronchitis (12 patients). Results of cytology analysis did not reveal atypia concerning for malignancy or any alternate diagnoses. CONCLUSION For bronchoscopic examination for chronic unexplained cough, diagnostic yield increased from 26%, attributable to directly visualized anatomical findings, to up to 68% upon inclusion of bronchial washings and endobronchial biopsies. The addition of microbiology cultures and tissue pathology analysis significantly increased the diagnostic yield of bronchoscopy in identifying the probable etiology of patients' chronic heretofore unexplained cough.