Sandbox:Ezici
Hydrops Fetalis
Overview
Historical Perspective
Hydrops fetalis was first discovered by Dr. John William Ballantyne, a Scottish physician and obstetrician, in 1892.
Classification
Hydrops Fetalis may be classified into two groups based on the presence or absence of rhesus iso-immunization:
- Immune Hydrops Fetalis
- Non-Immune Hydrops Fetalis (NIHF)
Pathophysiology
- It is thought that hydrops fetalis is caused by conditions with either increased rate of fluid transudation from the vascular compartment or decreased lymphatic return to the circulation.
- This is shown to be originated from developmental defects in microcirculation and lymphatic system, respectively.
- The potential causes may be immune or non-immune, and they often result in anemia and further hypoxia.
- The sympathetic system becomes activated due to hypoxia, and it causes blood redistribution with decreased blood flow to the liver and kidneys.
- Decreased blood flow to the liver and kidneys, results in decreased albumin, increased ADH, and increased activity of RAAS.
- Following these changes, the central venous pressure increases, which further results in decreased lymphatic return.
- As a result, hydrops fetalis (the accumulation of fluid, or edema, in at least two fetal compartments) occurs.
- The pathophysiology of non-immune causes also depend on the underlying conditions, include:
- Decreased ventricular filling during diastole (i.e. tachyarrhythmias)
- Increased central venous pressure due to the increased right heart pressure (i.e. cardiac tumors and subendocardial fibroelastosis)
- Obstruction of lymphatic drainage due to a mass (i.e. cystic hygroma)
Causes
Hydrops Fetalis is caused by either immune or non-immune conditions.
- Immune hydrops fetalis
- Antibodies may occur due to the exposure of non-self RBC antigens during the previous pregnancy or transfusion.
- In the next pregnancy, these antibodies may attack the fetal erythrocytes if the fetus has that antigen.
- Following the red blood cell destruction, hemolytic disease of the fetus and newborn (HDFN) may occur with a wide range of clinical outcome from only mild anemia to high output heart failure and hydrops fetalis.
- Rh disease is the major cause for immune-mediated hydrops fetalis; however, owing to preventative methods developed in the 1970s, the incidence of Rh disease has markedly declined.
- Rh disease can be prevented by administration of anti-D IgG (Rho (D) Immune Globulin) injections to RhD-negative mothers during pregnancy and/or within 72 hours of the delivery.
- Non-immune hydrops fetalis (NIHF)
- Currently, with the decreased prevelance of Rh disease, non-immune causes are responsible for up to 90% of cases.
- The most common causes of non-immune hydrops fetalis are hematologic diseases, and chromosomal abnormalities, followed by lymphatic anomalies, and cardiovascular diseases. Causes of NIHF include:
- Structural cardiac malformations (especially hypoplastic left heart, endocardial cushion defect)
- Arrhythmias
- Congenital lymphatic dysplasia
- Chromosomal abnormalities (Turner Syndrome, trisomy 13, trisomy 18, trisomy 21)
- Alpha-thalassemia
- Fetomaternal transfusion
- Infections (Parvo-B19, CMV, Adenovirus, Enterovirus)
- Twin to twin transfusion syndrome (both donor and recipient fetus)
- Congenital cystic adenomatoid malformation
- Diaphragmatic hernia
- Extrapulmonary sequestration
- Hydrothorax
- Chylothorax
- Noonan Syndrome
- Urethral Obstruction
- Prune belly syndrome
- Lysosomal storage disease
- Vascular tumors
- Teratoma
- Leukemia
- Hepatic tumors
- Neuroblastoma
- Meconium peritonitis
- Gastrointestinal obstructions
Epidemiology and Demographics
- In developed countries, the incidence of non-immune hydrops fetalis (NIHF) is 25-79 per 100.000 live born infants worldwide.
- The median gestational age (GA) at diagnosis of NIHF is 23 weeks.
- Gestational age is predictive of mortality, as preterm infants with this condition are more likely to die.
- The case-fatality rate of NIHF is ranged from 43.2% to 78.2%.
Risk Factors
References