Hydrops fetalis

Hydrops fetalis is excessive extravasation of fluid into the third space in a fetus which could be due to heart failure, volume overload, decreased oncotic pressure, or increased vascular permeability. Hydrops is defined as the accumulation of fluid +/- edema involving at least two fetal components, which may manifest as:

• fetal pleural effusion
• fetal pericardial effusion
• fetal ascites
• generalized body edema: fetal anasarca/nuchal edema/cystic hygroma
• placental enlargement
• polyhydramnios
• hepatomegaly 

Epidemiology

The estimated incidence is at ~1 in 2000 births although this can significantly vary according to different regions.

Pathology

It is considered a prenatal form of cardiac failure. It was traditionally divided into two broad groups:

• immune hydrops fetalis (IHF)
• non-immune hydrops fetalis (NIHF)

Etiology

Immune hydrops

Accounts for a minority (~10%) of cases in present-day pregnancies , although historically accounted for a larger proportion of cases in the early to mid 20 century:

• fetomaternal blood group incompatibility (including rhesus incompatibility): erythroblastosis fetalis

Non-immune hydrops

Accounts for a majority of cases and can arise from protean causes which include:

• chromosomal anomalies
  • Turner syndrome
  • trisomies
    • trisomy 13
    • trisomy 18
    • trisomy 21
• cardiac causes
  • abnormalities in fetal heart rate: e.g. fetal tachyarrhythmias
  • congenital cardiac anomalies
  • fetal cardiac tumors: cardiac rhabdomyoma
• twin pregnancy-related complications
  • twin to twin transfusion syndrome: in the recipient twin
  • twin reversed arterial perfusion sequence: in pump twin
• in utero infection(s)
  • congenital viral infection(s)
    • TORCH group
    • fetal parvovirus B19 infection: considered the most common infectious cause of hydrops; the mechanism is that of anemia
    • coxsackie viral infection
• fetal tumors capable of producing significant AV shunts
  • sacrococcygeal teratoma
  • hepatic hemangioendothelioma
  • placental chorioangioma
• inborn errors of metabolism
  • Gaucher disease
  • Niemann-Pick disease
• fetal hypoproteinemic states
  • congenital nephrotic syndrome
• congenital/fetal anemia(s)
  • hemoglobin Bart's (a.k.a. Hb Bart's hydrops fetalis syndrome) 
    • cause of alpha thalassemia 
    • relatively common cause in Southeast Asia
• fetal skeletal dysplasia(s)
• fetal lymphovascular anomalies
  • cystic hygroma
• high output flow states
  • vein of Galen aneurysmal malformation
  • umbilical vein thrombosis in cases of umbilical vein varix
• thoracic/pulmonary abnormalities: thought to be from a fetal venous obstruction
  • primary fetal hydrothorax
  • congenital pulmonary airways malformation
  • congenital diaphragmatic herniation
  • pulmonary sequestration

Radiographic features

Antenatal ultrasound

Sonographic features can be similar for both immune and non-immune hydrops and include:

• increased amniotic fluid volumes
• increased nuchal translucency (especially 1trimester )
• larger placental size (placentomegaly) / increased placental thickness (placental edema)
• presence of a fetal pleural or pericardial effusion
• generalized fetal body swelling: fetal anasarca and skin thickening
• umbilical venous dilatation

Treatment and prognosis

The overall prognosis can be variable, dependent on the underlying cause.

History and etymology

The term hydrops fetalis comes from the Latin meaning edema of the fetus .

Siehe auch:

• Perikarderguss
• Pätau-Syndrom
• Down-Syndrom
• Herzfehler
• Steißbeinteratom
• Turner-Syndrom
• Trisomie 18
• nuchal translucency
• Morbus Gaucher
• chromosomale Anomalien
• fetal pleural effusion
• in utero infection
• trisomies
• Rhabdomyom des Herzens
• placental thickness
• zystisches Lymphangiom
• amniotic fluid volumes
• fetal anaemia
• fetal pericardial effusion
• twin reversed arterial perfusion sequence
• fetal skeletal dysplasia
• Vena Galeni Malformation
• fetal tachyarrhythmias
• twin to twin transfusion syndrome (TTTS)
• primary fetal hydrothorax (PFHT)
• kongenitale Zwerchfellhernie
• fetale Tumoren
• fetal anasarca
• fetal parvovirus B19 infection
• erythroblastosis fetalis
• TORCH infections
• umbilical venous dilatation
• fetaler Aszites
• nuchal oedema
• Plazentamegalie
• Rhesus-Inkompatibilität
• Nabelvenenaneurysma
• congenital pulmonary airways malformation
• fetal pleural

und weiter:

• obstetric curriculum
• Ebstein anomaly
• Polyhydramnion
• antenatal features of Down syndrome
• kongenitale pulmonale Atemwegsmalformation (CPAM)
• fetal hepatomegaly
• Embryopathia rubeolosa
• Lues connata
• fetal toxoplasmosis
• endocardial fibroelastosis
• fetal hepatosplenomegaly
• fetale Hirntumoren
• fetal cardiomegaly
• fetal complete atrioventricular block
• fetal tachyarrhythmia
• fetal splenomegaly
• fetal cardiomyopathy
• absent ductus venosus
• fetal bradyarrhythmia
• primary fetal hydrothorax
• mirror syndrome
• placental chorioangiomatosis
• pulmonale Lymphangiektasie
• connatale Zytomegalie
• fetal atrial flutter
• TRAP sequence
• fetal goitre
• kongenitales mesoblastisches Nephrom
• fetale Struma
• feto-maternal rhesus incompatibility
• fetales perikardiales Teratom
• fetal supraventricular tachycardia
• haemolytic disease of the newborn
• erythema infectiosum
• fetal atrial fibrillation