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Updated: Feb 12, 2026
Local Anesthetic Thoracoscopy for Undiagnosed Pleural Effusion
Published on: November 10, 2023
From Dyspnea to Diagnosis: Neutrophilic Pleural Effusion With Elevated Adenosine Deaminase As the First Clue to
Syed A Moosa1,2,3, Lily Zonnoor1,2, Amauri Gomez2
1Rheumatology, Kings County Hospital, Brooklyn, USA.
Abstract:
Rheumatoid arthritis (RA) rarely announces itself with a pleural effusion, yet when it does, the biochemical and pleural fluid profile often leads to a suspicion of infectious etiology at first. We describe a 44‑year‑old woman whose initial manifestation of seropositive RA was a large, unilateral, neutrophil‑rich, adenosine‑deaminase (ADA)-positive pleural effusion. The case draws attention to a diagnostic pitfall: elevated pleural fluid ADA-although classically associated with tuberculous pleuritis-can also occur in rheumatoid pleuritis, highlighting that ADA levels must be interpreted in the full clinical context and should not, by themselves, prompt initiation of anti-tuberculous therapy. By combining serial fluid analysis with targeted serology, we avoided unnecessary antimycobacterial therapy, initiated immunosuppression early, and achieved complete radiographic resolution. The report emphasizes the need to identify extra-articular conditions (especially pleural involvement) as potential early indicators of RA development.
Insights
Rheumatoid arthritis can present with pleural effusion, a lung inflammation. Elevated adenosine deaminase (ADA) in pleural fluid, often linked to tuberculosis, can also indicate rheumatoid arthritis, necessitating careful clinical context evaluation.
Area of Science:
- Rheumatology
- Pulmonology
- Infectious Diseases
Background:
- Rheumatoid arthritis (RA) typically affects joints but can manifest with extra-articular symptoms.
- Pleural effusion is an uncommon initial presentation of RA.
- Biochemical analysis of pleural fluid can mimic infectious etiologies, complicating diagnosis.
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