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Purpose: To describe a case of a patient with acute systemic lupus erythematous (SLE) causing choroidal effusions and to report a novel technique for evaluation of the choroidal fluid which sheds light on effusion pathogenesis. Observations: A 37 year-old woman was referred for decreased vision, eye pain and shortness of breath. The patient had bilateral angle closure glaucoma from choroidal effusions and bilateral pleural effusions. Work-up revealed new onset acute SLE. A technique for obtaining suprachoroidal fluid is described, and the fluid was analyzed using Light's criteria and found to be exudative in nature. Conclusions and importance: There has been speculation as to pathogenesis of choroidal effusions in a variety of conditions, and many authors believe the most likely process to be transudative. The exudative nature of the fluid in our patient suggests that choroidal effusions in acute SLE are likely caused by inflammation, and not secondary to hypoalbuminemia or another transudative process. Similar analyses of suprachoroidal fluid in other disease processes may help elucidate the underlying pathogenesis and may possibly guide treatment.

A 62-year-old female presented to the emergency room with one-month history of epigastric abdominal pain, nausea and vomiting. She endorsed progressive dyspnea over two weeks. CT of the abdomen demonstrated bilateral pleural effusions and pancreatic inflammation, so the working diagnosis was pancreatitis. A diagnostic thoracentesis was performed and the pleural fluid analysis was classified as transudate by Light's criteria. Given the atypical features in history and concern for malignancy, fluid was sent for cytological examination and immunohistochemistry which suggested a mucinous malignancy. EGD revealed poorly differentiated signet ring cell adenocarcinoma of stomach. Patient underwent placement of indwelling pleural catheters for symptomatic improvement and was discharged to hospice. The decision whether to routinely send transudative effusions for cytological evaluation remains controversial. This case demonstrates the importance of using clinical judgement to guide that decision.

Light's criteria falsely label a significant number of effusions as exudates. Such exudative effusions with transudative etiologies are referred to as "pseduoexudates". In this review, we discuss a practical approach to correctly classify an effusion that may be a pseudoexudate. A PubMed search yielded 1996 manuscripts between 1990 and 2022. Abstracts were screened and 29 relevant studies were included in this review article. Common etiologies for pseudoexudates include diuretic therapy, traumatic pleural taps, and coronary artery bypass grafting. Here, we explore alternative diagnostic criteria. Concordant exudates (CE), defined as effusions where proteins in pleural fluid/serum (PF/SPr) > 0.5 and pleural fluid LDH level of >160 IU/L (>2/3 upper limit of normal) confer higher predictive value to the Light's criteria. Serum-pleural effusion albumin gradient (SPAG) > 1.2 g/dL and serum-pleural effusion protein gradient (SPPG) > 3.1 g/dL together yielded a sensitivity of 100% in heart failure and a sensitivity of 99% in hepatic hydrothorax whe n identifying pseudoexudates (Bielsa et al., 2012) [5]. Pleural fluid N-Terminal Pro Brain Natriuretic Peptide (NTPBNP) offered a specificity and sensitivity of 99% in identifying pseudoexudates when using a cut-off of >1714 pg/mL (Han et al., 2008) [24]. However, its utility remains questionable. Additionally, we also looked at pleural fluid cholesterol and imaging modalities such as ultrasound and CT scan to measure pleural thickness and nodularity. Finally, the diagnostic algorithm we suggest involves using SPAG >1.2 g/dL and SPPG >3.1 g/dL in effusions classified as exudates when there is a strong clinical suspicion for pseudoexudates., Competing Interests: Declaration of competing interest All authors declare that they have no conflicts of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)