Milky Way of the Thorax: A Unique Case of Chylothorax in Seropositive Rheumatoid Arthritis

Document Type

Conference Proceeding

Publication Date

5-2024

Publication Title

American Journal of Respiratory and Critical Care Medicine

Abstract

Introduction: Rheumatoid arthritis (RA) is known to cause a myriad of pulmonary manifestations, including interstitial lung disease, lung nodules, and pleural effusions. RA-associated pleural effusions are typically unilateral and asymptomatic. Typical fluid characteristics include a low pH(<7.3), low glucose (<60 mg/dL), and elevated LDH (> 700 U/L). While pseudochylothorax can result from chronic pleural inflammation related to RA, true chylothorax is an uncommon manifestation of RA. We present the first described case of co-existing chylothorax and pseudochylothorax in apatient with seropositive RA. Description: Our patient is a 60 year old male diagnosed with RA one year prior to presentation. He was initially managed with Methotrexate, which was switched to Etanercept, followed by Abatacept. He was referred to the Pulmonary clinic for exertional dyspnea for the past 3-4 months. HRCT showed small bilateral pleural effusions with basilar subpleural reticulations, as well as multiple noncalcified nodules. A diagnostic left thoracentesis was performed, which yielded 600cc of chylous fluid. Fluid analysis was consistent with a chylothorax(triglycerides 208 mg/dL, cholesterol 268 mg/dL, pH 7.18, glucose < 5 mg/dL, LDH 4,300 U/L, protein 6.5 g/dL). 16 days later, a right-sided thoracentesis was subsequently performed, with 480cc of cloudy fluid removed, and demonstrated a pseudochylothorax (triglycerides 92 mg/dL, cholesterol 257 mg/dL, pH 7.17, glucose < 5 mg/dL, LDH 3,639 U/L, protein 5.5 g/dL). Flowcytometry, cytology, and fluid culture were negative. Our patient has been followed for 5 months, with symptomatic improvement in dyspnea, and no recurrence of effusions on CT. Discussion: Chylothorax is defined by the presence of lymphatic fluid within the pleural cavity. In most cases of chylothorax triglycerides are > 110 mg/dL but < 200 mg/dL. Known etiologies include trauma, congenital lymphatic abnormalities, neoplasm, and infection. 10% of cases are idiopathic. There are very few cases reported of chylothorax associated with RA, and none reported with a pseudochylothorax also present, making our case the first documented case with a chylothorax and pseudochylothorax. Our patient’s chylothorax fit some characteristics of a true RA-associated pleural effusion (low pH, low glucose, and elevated LDH), but additionally fit the diagnostic criteria for true chylothorax with triglycerides > 110 mg/dL. Interestingly, our patient had a triglyceride level >200, which is not typically seen in cases of chylothorax, further underscoring the distinctive nature of our case.

Volume

209

Issue

Suppl

First Page

A1908

Comments

International Conference of the American Thoracic Society, May 17-22, 2024, San Diego, CA

DOI

10.1164/ajrccm-conference.2024.209.1_MeetingAbstracts.A1908

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