BLINDED BY THE LIGHT: A CASE OF MALIGNANT PLEURAL EFFUSION WITH TRANSUDATIVE PROPERTIES

Abstract

SESSION TITLE: Tuesday Medical Student/Resident Case Report Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/22/2019 01:00 PM - 02:00 PM INTRODUCTION: Light’s criteria is routinely used to help aid in the diagnosis and treatment of pleural effusions by categorizing them into transudates or exudates. Pleural effusions due to malignancy and infection are classically exudative, while effusions from heart failure, cirrhosis, and renal failure are examples of usual transudates (1). When exceptions to this pattern do occur, it is most often that a transudate is misclassified as an exudate (1). Presented is a case where a transudative effusion was later discovered to be malignant due to likely concurrent hepatic hydrothorax. CASE PRESENTATION: A 59 year-old male with a history of alcoholic cirrhosis presented with respiratory distress and right upper quadrant pain was found to have complete opacification of the left hemithorax on chest X-ray. Upon admission, the pulmonary service was consulted where bedside evaluation confirmed a large right pleural effusion anechoic by ultrasound. Diagnostic thoracentesis was consistent with a transudative effusion with pleural protein 1.1, serum protein 5.6, pleural lactate dehydrogenase 76, and serum lactate dehydrogenase 269. Hepatic hydrothorax was considered to be the likely etiology given presence of ascites and a history of cirrhosis. Medical cytology however later revealed atypical neoplastic cells. Abdominal imaging revealed a large mass in the right hepatic lobe. IR-guided biopsy revealed metastatic adenocarcinoma with a primary cholangiocarcinoma. Prior to oncologolical evaluation for chemotherapeutic options, the patient decompensated with worsening encephalopathy and respiratory distress from re-accumulation of pleural fluid and abdominal ascites. Given overall grave prognosis, goals of care discussions were held and comfort care was initiated with the patient passing comfortably shortly thereafter. DISCUSSION: Light’s criteria are routinely used to help aid in the diagnosis and treatment of pleural effusions by categorizing them into transudates or exudates. Certain etiologies of pleural effusions are classically transudative, while others are exudative (1). When pleural studies do not meet Light’s criteria for an exudative effusion, physicians will tend to consider that malignancy and infection are ruled out (2, 3). This can lead to a missed or incorrect diagnosis since malignant effusions have been described in the literature to be transudative in as much 10.6% (4) of cases. We describe a case where pleural studies did not meet criteria for an exudative effusion, so a malignant etiology was initially considered to be unlikely. However, medical cytology later showed malignant cells, leading to further work-up revealing the primary underlying cholangiocarcinoma. CONCLUSIONS: When an effusion is transudative, one cannot assume that malignancy is ruled out, otherwise a deadly diagnosis may be missed. Reference #1: Light RW. “The Light criteria. The beginning and why they are useful 40 years later.” Clinical Chest Medicine 2013; 34(1): 21-6. Reference #2: McGrath EE, Anderson PB. “Diagnosis of pleural effusion: a systematic approach.” American Journal of Critical Care 2011; 20(2): 119-27. Reference #3: Thomas R, Cheah HM, Creaney J, Turlach BA, Lee YCG. “Longitudinal measurement of pleural fluid biochemistry and cytokines in malignant pleural effusions.” Chest 2016; 149(6): 1494-500. DISCLOSURES: no disclosure on file for Alfredo Astua; No relevant relationships by Dawn Maldonado, source=Web Response No relevant relationships by Michael Megally, source=Web Response