Outcome of patients with non specific pleuritis after medical thoracoscopy

Introduction: A number of exudative pleural effusions(EPE) are diagnosed as non specific pleuritis(NSP), after investigation with medical thoracoscopy(MT). It remains unclear if this is a specific clinical entity(idiopathic pleuritis). Aim: To assess the long-term outcome of cases with post-MT histological diagnosis of NSP. Methods: All patients with undiagnosed EPE, further investigated with MT, and diagnosed as NSP were enrolled in study. Parapneumonic EPE were excluded. Demographic, laboratory, imaging data and main thoracoscopic findings were recorded. All cases were followed up for 2 years. Patients with persistent/recurrent EPE or suspicious for malignancy findings were further investigated with video assisted thoracoscopic surgery(VATS). Results: 127 patients with EPE, investigated with MT were screened. 57 patients(age mean ±SD 65.3±12.9) diagnosed as NSP were enrolled in the study. Three cases(5.2%) developed malignancy(one metastatic lung and two breast cancers) during the follow-up period. A probable cause was established in 16 cases(pleuropericarditis caused by Rickettsia infection n=3, benign asbestos pleuritis n=3, rheumatoid pleurisy n=3, drug induced n=3, post traumatic n=2, paramalignant n=2). In the remaining cases(n=38) EPE was considered due to true 9idiopathic pleuritis´, since it resolved spontaneously in 89.2± 62.3 days. Among them, 5 patients with suspicious for malignancy MT findings were referred for VATS, without establishing a different diagnosis. Conclusion: The majority of patients with NSP followed a benign course, without identifying a specific cause, implying the clinical diagnosis of idiopathic pleuritis. However, close and long-term follow-up should be undertaken in all cases.