Abstract：
Fetal primary hydrothorax is a rare congenital anomaly with an estimated incidence of 1:10,000-15,000 pregnancies, with an unpredictable clinical course, ranging from spontaneous resolution to fetal death. A case of unilateral fetal pleural effusion was diagnosed at 35th week of gestation during a routine ultrasonographic fetal assessment in an uncomplicated pregnancy. A large echogenic collection of fluid was revealed in the right pleural cavity, together with atelectasis of the right lung, as well as displacement of heart and mediastinal structures to the left side of thorax. The patient was also diagnosed with polyhydramnios and there was a disproportion of heart ventricles volume. No other fetal structural abnormalities were detected and there were no symptoms of edema. Fetal biometrics was consistent with the gestational age. In echocardiography, fetal heart was structurally and functionally normal. Screening tests for congenital infections of the fetus were negative. Autoimmune fetal hydrops was excluded after laboratory tests. There was no parents\' consent for the analysis of the karyotype. The patient presented clinical symptoms and was diagnosed with Herpes simplex virus infection and was treated with oral acyclovir. Serial fetal ultrasound exams showed gradual decrease in pleural fluid volume up to complete resolution in 38th week of pregnancy. Pregnancy was ended in the 38th week of gestation with a cesarean delivery of a healthy neonate. It is yet to be determined if there is a direct association between Herpes simplex virus infection in pregnancy and the risk of fetal pleural effusion. The incidence of fetal pleural effusion is low and the neonatal outcome difficult to be predicted. The optimum management of fetal pleural effusion should be subject to further studies to determine the best clinical practice.
摘要：
胎儿原发性胸水是一种罕见的先天性异常，估计发生率为1：10,000-15,000妊娠，不可预测的临床过程，从自发消退到胎儿死亡。在妊娠第35周进行常规超声检查胎儿评估时，诊断出一例单侧胎儿胸腔积液。在右胸膜腔中发现了大量的回声液体，以及右肺的肺不张,以及心脏和纵隔结构向胸腔左侧移位。该患者还被诊断为羊水过多，并且心室容积不成比例。没有检测到其他胎儿结构异常，也没有水肿症状。胎儿生物识别与胎龄一致。在超声心动图中，胎儿心脏结构和功能正常.胎儿先天性感染筛查试验均为阴性。实验室检查后排除自身免疫性胎儿水肿。没有父母同意进行核型分析。患者出现临床症状，诊断为单纯疱疹病毒感染，口服阿昔洛韦治疗。连续的胎儿超声检查显示，在妊娠第38周，胸腔积液逐渐减少，直至完全消退。妊娠在妊娠第38周结束，剖腹产健康的新生儿。尚未确定妊娠中单纯疱疹病毒感染与胎儿胸腔积液的风险之间是否存在直接关联。胎儿胸腔积液发生率低，新生儿结局难以预测。胎儿胸腔积液的最佳管理应进行进一步研究，以确定最佳的临床实践。
