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Pleural effusion or hydrothorax

  • We are among the centres with the most extensive experiences in fetal surgery in the world, with more than 2000 interventions performed, the shortest surgical times reported in the medical literature and, consequently, very low rates of complications.  
  • We have more than 20 years of experience in the treatment of fetal hydrothorax by shunt. Although it is a consolidated therapy in many hospitals, as it is a rare pathology, it is essential to have an experienced team to obtain good results.  
  • As a pioneering development centre in fetal surgery, we continue to research and continuously incorporate technologies that further improve technical accuracy. 
  • We are a multidisciplinary team, which allows us to approach surgery in a comprehensive way: from the choice of the best strategy to individualized postnatal follow-up. 

Pleural effusion or hydrothorax

What is pleural effusion or hydrothorax? Why does it occur?

In the chest, the lungs are surrounded by two layers of membrane called the pleurae, which separate them from the heart and ribs. Fetal pleural effusion or hydrothorax (meaning 'water in the chest') is a build-up of fluid in the space between the lungs and the pleurae. 

The cause of pleural effusion in a fetus may include genetic problems, infections and malformations, especially heart or lung malformations. If no associated malformations are detected and the genetic and infection studies are normal, the most common cause is a problem in the lymph ducts (the vessels that connect the lymph nodes of the body) that after birth is called a primary chylothorax. 

Fetal hydrothorax is rare, occurring in 1 in 5000 pregnancies. 

What are the consequences of fetal hydrothorax?

The prognosis for each individual case depends on the amount of fluid in the chest, which can become so significant that it compresses the lungs, keeping them collapsed, and also the heart, hindering its function. Therefore, hydrothorax can produce: 

  • Compression and tightness of the lungs, which if maintained for a long time can hinder their development (pulmonary hypoplasia) and prevent the baby from breathing after birth due to an underdevelopment of the lungs. 
  • Compression of the heart, which hinders its normal function and can lead to heart failure, development of hydrops fetalis (accumulation of fluid in other parts of the body) and finally fetal death. 
How is fetal hydrothorax diagnosed?

Fetal pleural effusion or hydrothorax is easily detected by fetal ultrasound, as the amount of fluid in the chest surrounding the lungs is usually very evident. It usually occurs between the 24th and 30th week of pregnancy. Upon detection, a series of tests should be performed to confirm that it is an isolated finding, and it may also be a chylothorax (lymphatic fluid in the pleurae) with a good postnatal prognosis.

These tests are: 

  • High-resolution fetal ultrasound to rule out the presence of other malformations, growth disorders, and alterations in circulation and the amount of amniotic fluid.  
  • Fetal echocardiography to perform a specialized evaluation of fetal heart anatomy and function. 
  • Magnetic resonance imaging, which can be useful for evaluating chest organs in more complex cases.  
  • Amniocentesis for genetic and metabolism studies, which are more frequent when pleural effusion or hydrothorax appears already in the first half of gestation, and to also rule out fetal infections. 
What is the treatment of fetal hydrothorax?

The indication for fetal treatment will be established when there is a clear risk of pulmonary complications or the development of hydrops fetalis. There are two treatment options: 

  • Thoracentesis (fluid drainage): this is performed with ultrasound monitoring in the consultation room, using a small needle (1 mm) to aspirate the liquid. This relieves pressure on the baby's lungs, which then expand and occupy most of the chest normally, and also improves heart function, reversing any signs of hydrops fetalis. The aspirated fluid will be analysed to determine its origin and this can help identify the cause of its accumulation and guide treatment. In up to 10% of cases a single puncture may be sufficient as a treatment and completely resolves the hydrothorax. But in most cases, especially if there are already signs of hydrops fetalis, the hydrothorax accumulates again 24–48 hours after the procedure. 
  • Thoracoamniotic shunt: this is also performed with ultrasound monitoring, but requires local anaesthetic for the pregnant woman and fetal anaesthesia, so it is performed in the operating room. A small plastic tube with spiral-shaped tips is placed, connecting the fetal chest to the amniotic cavity. Due to the high pressure inside the fetal chest, the fluid drains continuously out of the fetus and into the amniotic cavity. This treatment provides relief from hydrothorax, continuous decompression of the fetal chest and offers the best opportunity to prevent hypoplasia of the lungs and the development of hydrops fetalis. 
What appointments are needed for fetal surgery?

An in-patient admission of the pregnant woman will initially last 1 day and afterwards weekly check-ups with examination and ultrasound will be required, and she will have to maintain a low-activity lifestyle mainly at home until the end of pregnancy. Ultrasound scans will allow the monitoring of the correct development of the fetus and the continued correct positioning of the drainage, since its dislocation would lead to the reappearance of hydrops fetalis.

In case dislocation occurs near term, an evacuating thoracentesis just before birth may be necessary to prevent difficulties in the baby's breathing and to aid in its immediate resuscitation. The aim is to ensure that childbirth can be carried out at the end of pregnancy without the need to induce it prematurely

In many cases, pregnant women who have babies with fetal pleural effusion or hydrothorax can give birth at their local hospital. But in cases with large effusions in which it has been necessary to perform fetal treatment, babies must be born in a centre like ours, which offers specialized care for both the pregnant woman and the newborn.  

Why BCNatal - Sant Joan de Déu?

The treatment of fetal pleural effusion or hydrothorax by shunt has been a fully consolidated therapy for many years and is performed in many hospitals around the world. However, pleural effusion or hydrothorax is an uncommon pathology, so the operator's experience is crucial to obtaining good results. We have been delivering this therapy for more than 20 years. 

As a pioneering development centre in fetal surgery, we continuously research and incorporate technologies that further improve accuracy, such as computer guidance techniques for better access to the fetal chest

For parents who wish to continue their pregnancy care and have their baby with us, we offer a fetal therapy team with the best survival and quality of life figures that can currently be obtained. Before surgery we evaluate each case in detail, performing very high-resolution ultrasound and magnetic resonance tests, and analyse them in multidisciplinary teams that include experts in each of the fields, including fetal medicine, fetal and paediatric surgery, neonatologists, radiologists and any other specialty that may be necessary. We will discuss the case in detail with the parents and talk about the best options for the baby.

Parents will be able to speak in detail not only with specialists in medicine and fetal surgery, but also with paediatricians who are experts in the monitoring and evolution of these children, to get to know in detail the expected evolution in each case and the best options. 

To the excellence of the prenatal team is added a third-level paediatric centre such as SJD Barcelona Children's Hospital, with teams formed by a large number of specialists with specific training in neonatal intensive care and who have the best and most modern technology, since babies born with pleural effusion or hydrothorax may also need a chest drain to be placed after birth, and sometimes even intubation and respiratory support. In more complicated cases, very occasionally minimally invasive treatment of lymphatic malformations in the chest and lungs may be necessary.

Neonatologists, also part of the prenatal team, will continue to care for the baby once it is born and plan for possible interventions as necessary. For surveillance during the first days after birth, the hospital has highly qualified medical and nursing professionals caring for these delicate patients 24 hours a day, 365 days a year. 

Once discharged, our Paediatric teams will follow the baby for the first few years and take care of him or her to achieve optimal development and to solve any problems in this very fundamental part of life. 

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