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Diagnosing Sarcoidosis: Endosonography versus Bronchoscopy

Authors

Tori Socha

The incidence of sarcoidosis, a multisystem granulomatous disease of unclear etiology, is, according to researchers, high, with up to 40 cases per 100,000 individuals. In addition, mortality related to sarcoidosis is increasing. The disease is characterized by tissue accumulation of noncaseating granulomas and affects the lungs and intrathoracic lymph nodes in nearly all patients.

Diagnosis of sarcoidosis relies on tissue verification of noncaseating granulomas according to current recommendations. The current diagnostic standard is bronchoscopy with transbronchial biopsies, which has, according to researchers, “moderate sensitivity in assessing granulomas.”

Noting that, “Endosonography with intrathoracic modal aspiration appears to be a promising diagnostic technique,” researchers recently conducted a randomized clinical multicenter trial to assess the diagnostic yield of bronchoscopy versus endosonography in the diagnosis of stage I/II sarcoidosis. They reported trial results in JAMA [2013;309(23):2457-2464].

The trial was conducted at 14 centers in 6 countries between March 2009 and November 2011; participants were 304 consecutive patients with suspected pulmonary sarcoidosis (stage I/II) in whom tissue confirmation of noncaseating granulomas was indicated.

The interventions were bronchoscopy with transbronchial and endobronchial lung biopsies or endosonography (esophageal or endobronchial ultrasonography) with aspiration of intrathoracic lymph nodes. All patients also underwent bronchoalveolar lavage.

The primary study outcome was the diagnostic yield for detecting noncaseating granulomas in patients with a final diagnosis of sarcoidosis. Secondary outcomes were the complication rate in both groups and sensitivity and specificity of bronchoalveolar lavage in the diagnosis of sarcoidosis.

The primary end point was the detection of granulomas or clusters of epithelioid cells concordant with a granulomatous inflammation.

The 304 eligible patients were randomized to 1 of 2 groups: (1) conventional bronchoscopy (n=149) or (2) endosonography (n=155). One of the patients in the endosonography group was excluded from the analysis due to nonparticipation in either the procedure or follow-up. One patient in the bronchoscopy group insisted later on undergoing endosonography and 1 in the endosonography group inadvertently underwent bronchoscopy, yielding a final cohort of 301 patients undergoing endosonography according to protocol.

The groups were well balanced for major characteristics at baseline. In both groups, the majority were men (62% in the bronchoscopy group and 58% in the endosonography group), and mean age was 41 in the bronchoscopy group and 45 in the endosonography group. Fatigue and cough were the most prevalent symptoms in both groups.

There was a significant difference in the number of granulomas detected at endosonography compared with bronchoscopy (114 vs 72 patients; 74% vs 48%; P<.001). Diagnostic yield to detect granulomas for endosonography was 80% compared with 53% for bronchoscopy (P<.001).

There were 2 serious adverse events in the bronchoscopy group and 1 in the endosonography group; all 3 patients had a full recovery.

Sensitivity of the bronchoalveolar lavage for sarcoidosis based on CD4/CD8 ratio was 54% for flow cytometry and 24% for cytospin analysis.

In conclusion, the researchers said, “Among patients with suspected stage I/II pulmonary sarcoidosis undergoing tissue f=confirmation, the use of endosonographic nodal aspiration compared with bronchoscopic biopsy resulted in greater diagnostic yield.”

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