fetal pleural effusion

Fetal pleural effusions (FPE) refer to an accumulation of pleural fluid in utero. It can refer to either a fetal chylothorax or a fetal hydrothorax.

Pathology

A fetal pleural effusion can occur as part of hydrops fetalis, in association with other anomalies without hydrops or in isolation - primary pleural effusion/primary fetal hydrothorax (PFHT).

Causes

Any cause of hydrops fetalis is a potential etiological factor in a fetal pleural effusion.

Associations

In addition to hydrops fetalis, a pleural effusion can be associated with numerous other underlying anomalies:

Radiographic features

Antenatal ultrasound

Classically seen as anechoic fluid surrounding one or both the lungs (which are echogenic) - batwing appearance.

Ancillary sonographic features include:

  • may show other features of hydrops if it occurs in association
  • there maybe presence of polyhydramnios (if severe)

Treatment and prognosis

The clinical course is variable and dependent on etiology. The presence of a pleural effusion early in pregnancy (i.e. first trimester) is often associated with a poor fetal outcome .

Management options are also dependent on other underlying factors:

  • thoracocentesis and drainage of the effusion: fluid can however reaccumulate within 24-48 hours
  • insertion of pleural-amniotic shunts