Nontraumatic Chylothorax in the Setting of Superior Vena Cava Stenosis

<strong>Introduction</strong>Chylothorax is a rare but potentially morbid complication following thoracic surgery. Nontraumatic chylothorax is even less common and typically is due to malignancy, congenital or idiopathic disorders of the lymphatic system, systemic diseases, and infection [1]. Here, the authors present a case of nontraumatic chylothorax due to central venous stenosis.<b>Case Presentation</b><br>A 57-year-old man with a history of renal failure and previous renal transplantation complicated by rejection requiring dialysis presented to the emergency room with the acute onset of dyspnea, nonproductive cough, and an inability to lay flat. He had a history of prior left tunneled internal jugular dialysis catheter placement and left upper extremity dialysis fistula, which had previously required multiple fistulagrams for prolonged bleeding and elevated venous pressures. During examination, his chest x-ray showed a large left pleural effusion and he underwent thoracentesis by the emergency medicine team with evacuation of 2 L of turbid fluid.<br>Given his chronic immunosuppression, he was admitted by internal medicine for initiation of intravenous (IV) antibiotics. Thoracic surgery, transplant infectious disease, and nephrology were consulted following admission. He underwent an echocardiogram, which did not demonstrate congestive heart failure. A computed tomography (CT) scan demonstrated right internal jugular occlusion, superior vena cava (SVC) stenosis, prominent thoracic venous collaterals, and cervical and mediastinal lymphadenopathy (Figures 1 and 2). His pleural fluid cytology and cultures were negative, but testing indicated the presence of chylomicrons and his triglyceride level was 1154 mg/dL, which was consistent with a chylothorax.<b><br></b>His IV antibiotics were discontinued, and he was placed on a medium chain triglyceride diet with octreotide three times daily. A cervical lymph node biopsy was negative for lymphoma, and he was monitored closely as an outpatient for recurrence. He continued to reaccumulate chylous fluid despite dietary modifications and required additional thoracenteses.<br>Subsequently, the decision was made to proceed with a venogram and possible SVC stent placement. If this were unsuccessful, he would undergo thoracoscopic thoracic duct ligation. He was found to have hemodynamically significant stenosis of the superior SVC resulting in a 21 mm Hg pressure gradient between the left innominate vein and central SVC. He underwent successful stent placement with decompression of previously visualized left thoracic venous collaterals (Figure 3). After stent placement the pressure gradient was reduced to 1 mm Hg. The patient subsequently has remained stable, with resolution of his chylothorax without the need for further interventions.<br>Learn more: https://www.ctsnet.org/article/nontraumatic-chylothorax-setting-superior-vena-cava-stenosis

<strong>引言</strong>乳糜胸（chylothorax）是胸外科术后少见但可引发严重不良预后的并发症。非创伤性乳糜胸更为罕见，其病因通常包括恶性肿瘤、淋巴系统先天性或特发性异常、全身性疾病以及感染[1]。本文报告1例由中心静脉狭窄引发的非创伤性乳糜胸病例。<strong>病例报告</strong><br>患者为57岁男性，有肾衰竭病史，曾行肾移植术，术后出现排斥反应需依赖透析治疗，因急性起病的呼吸困难、干咳、无法平卧就诊于急诊室。患者既往曾留置隧道式颈内静脉透析导管，并建立左侧上肢透析动静脉瘘，此前因瘘管持续出血及静脉压升高多次行瘘管造影术。<br>接诊时胸部X线检查提示左侧大量胸腔积液，急诊团队为其行胸腔穿刺术（thoracentesis），引流出2L浑浊液体。<br>考虑到患者长期免疫抑制状态，内科将其收入院并启动静脉（IV）抗菌药物治疗。入院后邀请胸外科、移植感染科及肾内科会诊。患者行超声心动图（echocardiogram）检查，未提示充血性心力衰竭。胸部计算机断层扫描（computed tomography, CT）显示右侧颈内静脉闭塞、上腔静脉（superior vena cava, SVC）狭窄、胸壁静脉侧支循环显著，同时存在颈部及纵隔淋巴结肿大（图1、图2）。胸腔积液细胞学检查及培养结果均为阴性，但检测提示乳糜微粒阳性，甘油三酯水平达1154mg/dL，符合乳糜胸诊断。<br>遂停用静脉抗菌药物，给予患者中链甘油三酯饮食联合奥曲肽（octreotide）每日三次治疗。颈部淋巴结活检未提示淋巴瘤，患者以门诊形式密切随访以监测复发情况。尽管调整了饮食，患者胸腔乳糜液仍持续积聚，需再次行胸腔穿刺术。<br>随后，团队决定为患者行静脉造影术（venogram），必要时置入上腔静脉支架。若该方案无效，则计划行胸腔镜下胸导管结扎术。术中发现患者上腔静脉存在具有血流动力学意义的狭窄，左侧头臂静脉与中央上腔静脉间压力梯度达21mmHg。患者成功置入支架，此前可见的左侧胸壁静脉侧支循环得以减压（图3）。支架置入后，压力梯度降至1mmHg。后续患者病情保持稳定，乳糜胸完全缓解，无需进一步干预。<br>了解更多：https://www.ctsnet.org/article/nontraumatic-chylothorax-setting-superior-vena-cava-stenosis