Heron Werner, MD & Pedro Daltro, MD
ClÃnica de Diagnóstico por Imagem (CDPI) & Instituto Fernandes Figueira (IFF) – FIOCRUZRio de Janeiro – Brazil
Dorothy I. Bulas M.D.
Professor of Radiology and Pediatrics
Children"s National Medical Center
George Washington University Medical Center
111 Michigan Ave, NW,  Washington D.C. 20010
Hydrothorax or pleural effusions is an accumulation of serous fluid in the pleural cavity. The etiology is unknown, but probably may result from overproduction of lymph or problems in the reabsorption. It may be isolated or associated with one of a broad spectrum of maternal and fetal disorders, including immune and non immune anemia; chromosomal anomalies such as trisomy 21 and 45,X0; over 50 genetic and sporadic syndromes; infections such as toxoplasmosis, rubella, cytomegalovirus, herpes simplex and parvovirus; cardiac and metabolic abnormalities, pulmonary masses and abnormalities of the placenta and umbilical cord. The origin of primary hydrothoraces are chylous.
Hydrops fetalis is defined as fetal skin edema plus effusions in two of three serous cavities including the peritoneal, pleural, or pericardial cavities (Table 1). The relative proportions of these findings can vary, and, in occasional cases, the ascites can be the only real abnormality seen. Fetal ascites can result from severe hemolytic anemia or be a part of a variety of non immune causes that generally have portal hypertension in common. Hydrops fetalis can be divided into immune and nonimmune. In immune hydrops the Rh blood group immunization is the most common. So, the difference between immune and non immune hydrops can be done by the maternal antibody screen. The non immune fetal hydrops is more common, because with the use of anti-D Y-globulin decreased the number of immune hydrops, and with the augmentation of using prenatal ultrasound increased the detection of non immune fetal hydrops. Many causes can be associated with non immune hydrops, but in around 15% of cases, no specific etiologic factor can be detected (Table 2).
|
Table 1: Caracteristics of hydrops fetalis
|
|
Skin edema
|
|
Pleural effusion
|
|
Pericardia effusion
|
|
Ascites
|
|
Polyhydramnios
|
|
Placental edema
|
|
Table 2: Some causes of hydrops fetalis
|
|
Fetal anemia (isoimmunization, fetal infection, hemolysis or hemorrhage)
|
|
Cardiac failure (structural heart defect or rhythm anomalies)
|
|
Arteriovenous malformation (sacrococcigeal teratoma)
|
|
Pulmonary defects
|
|
Cranial defects
|
|
Gastrointestinal and hepatic defects
|
|
Renal defects (hypoalbuminemia)
|
|
Inhered metabolic disorders
|
|
Genetic syndromes and chromosomal abnormalities
|
|
Placental abnormalities (arteriovenous malformations)
|