Non-specific pleuritis: long-term follow-up outcomes.

Background: The definitive etiology of nonspecific pleuritis (NSP), the influence of the type of pleural biopsy on clinical results and the minimum duration of follow-up is controversial.

Research design and methods: A retrospective, observational study of patients ≥ 18 years with NSP confirmed by closed pleural biopsy (CPB), local anesthesia pleuroscopy (LAP), or video-assisted thoracic surgery (VATS).

Results: A total of 167 patients were included (mean follow-up, 14.4 months), of which 25 (15%) were diagnosed within one month; [15 (60%) malignant]. Of the remaining 142 pleural effusions (PEf), 69 (48.6%) were idiopathic; 49 (34.5%) not-malignant and 24 (16.9%) malignant (4 mesotheliomas and 20 metastasic). The diagnosis of NSP was established by CPB (7; median time to diagnosis, 9.4 months), LAT (5; 15.8 months), and VATS (8; 13.5 months) (p = 0.606). Sixty-eight patients (40.7%) died during follow-up (mean time, 12 months).

Conclusions: In a substantial percentage of patients diagnosed with NSP, a definitive diagnosis will not be obtained, a relevant number of patients will develop a malignant PEf. The diagnostic procedure used for the diagnosis of NSP does not seem to influence delay in the diagnosis of malignant PEf. The data obtained suggest that follow-up should be maintained for at least 24 months.