Hydrops fetalis
Encyclopedia
Hydrops fetalis is a condition in the fetus
characterized by an accumulation of fluid, or edema
, in at least two fetal compartments. By comparison, hydrops allantois or hydrops amnion are an accumulation of excessive fluid in the allantoic
or amniotic space
respectively.
The edema
is usually seen in the fetal subcutaneous tissue, sometimes leading to spontaneous abortion. It is a prenatal form of heart failure, in which the heart is unable to satisfy its demand for a high amount of blood flow.
, when the heart needs to pump a much greater volume of blood to deliver the same amount of oxygen. This anemia can have either an immune or non-immune cause. Non-immune hydrops can also be unrelated to anemia, for example if a tumor or congenital cystic adenomatoid malformation
increases the demand for blood flow. The increased demand for cardiac output leads to heart failure, and corresponding edema.
scans. Prenatal ultrasound scanning enables early recognition of hydrops fetalis and has been enhanced with the introduction of MCA Doppler.
Severely anemic fetuses can be treated with blood transfusions while still in the womb.
Fetus
A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...
characterized by an accumulation of fluid, or edema
Edema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...
, in at least two fetal compartments. By comparison, hydrops allantois or hydrops amnion are an accumulation of excessive fluid in the allantoic
Allantois
Allantois is a part of a developing animal conceptus . It helps the embryo exchange gases and handle liquid waste....
or amniotic space
Amniotic sac
The amniotic sac is the sac in which the fetus develops in amniotes. It is a tough but thin transparent pair of membranes, which hold a developing embryo until shortly before birth. The inner membrane, the amnion, contains the amniotic fluid and the fetus. The outer membrane, the Chorion,...
respectively.
Presentation
Locations can include:- subcutaneous tissueSubcutaneous tissueThe hypodermis, also called the hypoderm, subcutaneous tissue, or superficial fascia is the lowermost layer of the integumentary system in vertebrates. Types of cells that are found in the hypodermis are fibroblasts, adipose cells, and macrophages...
/scalpScalpThe scalp is the anatomical area bordered by the face anteriorly and the neck to the sides and posteriorly.-Layers:It is usually described as having five layers, which can conveniently be remembered as a mnemonic:... - pleura (pleural effusionPleural effusionPleural effusion is excess fluid that accumulates between the two pleural layers, the fluid-filled space that surrounds the lungs. Excessive amounts of such fluid can impair breathing by limiting the expansion of the lungs during ventilation.-Pathophysiology:...
) - pericardiumPericardiumThe pericardium is a double-walled sac that contains the heart and the roots of the great vessels.-Layers:...
(pericardial effusionPericardial effusionPericardial effusion is an abnormal accumulation of fluid in the pericardial cavity. Because of the limited amount of space in the pericardial cavity, fluid accumulation will lead to an increased intrapericardial pressure and this can negatively affect heart function...
) - abdomenAbdomenIn vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
(ascitesAscitesAscites is a gastroenterological term for an accumulation of fluid in the peritoneal cavity.The medical condition is also known as peritoneal cavity fluid, peritoneal fluid excess, hydroperitoneum or more archaically as abdominal dropsy. Although most commonly due to cirrhosis and severe liver...
)
The edema
Edema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...
is usually seen in the fetal subcutaneous tissue, sometimes leading to spontaneous abortion. It is a prenatal form of heart failure, in which the heart is unable to satisfy its demand for a high amount of blood flow.
Classification and causes
Hydrops fetalis usually stems from fetal anemiaAnemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
, when the heart needs to pump a much greater volume of blood to deliver the same amount of oxygen. This anemia can have either an immune or non-immune cause. Non-immune hydrops can also be unrelated to anemia, for example if a tumor or congenital cystic adenomatoid malformation
Congenital cystic adenomatoid malformation
Congenital cystic adenomatoid malformation is a congenital disorder similar to bronchopulmonary sequestration. In CCAM, usually an entire lobe of lung is replaced by a non-working cystic piece of abnormal lung tissue. This abnormal tissue will never function as normal lung tissue.In most cases the...
increases the demand for blood flow. The increased demand for cardiac output leads to heart failure, and corresponding edema.
Immune causes
- Rh diseaseRh diseaseRh disease is one of the causes of hemolytic disease of the newborn...
is a cause for immune mediated hydrops fetalis; however, owing to preventative methods developed in the 1970s Rh disease has markedly declined. Rh diseaseRh diseaseRh disease is one of the causes of hemolytic disease of the newborn...
can be prevented by administration of anti-D IgG (Rho(D) Immune GlobulinRho(D) Immune GlobulinRho Immune Globulin is a medicine given by intramuscular injection that is used to prevent the immunological condition known as Rhesus disease...
) injections to RhD-negative mothers during pregnancy and/or within 72 hours of the delivery. However a small percentage of pregnant mothers are still susceptible to Rh disease even after having been administered anti-D IgG (Rho(D) Immune Globulin)
Non-Immune causes
The non-immune form of hydrops fetalis has many causes including:- Iron deficiency anemiaIron deficiency anemiaIron-deficiency anemia is a common anemia that occurs when iron loss occurs, and/or the dietary intake or absorption of iron is insufficient...
- Paroxysmal supraventricular tachycardia resulting in Congestive Heart FailureCongestive heart failureHeart failure often called congestive heart failure is generally defined as the inability of the heart to supply sufficient blood flow to meet the needs of the body. Heart failure can cause a number of symptoms including shortness of breath, leg swelling, and exercise intolerance. The condition...
- Deficiency of the enzyme beta-glucuronidase. This enzyme deficiency is the cause of the lysosomal storage diseaseLysosomal storage diseaseLysosomal storage diseases are a group of approximately 50 rare inherited metabolic disorders that result from defects in lysosomal function...
called Mucopolysaccharidosis Type VII. - Parvovirus B19Parvovirus B19The B19 virus, generally referred to as parvovirus B19 or sometimes erythrovirus B19, was the first known human virus in the family of parvoviruses, genus erythrovirus...
(Fifth Disease) infection of the pregnant woman. - Maternal syphilisSyphilisSyphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subspecies pallidum. The primary route of transmission is through sexual contact; however, it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis...
. - α thalassemiaAlpha-thalassemiaAlpha-thalassemia is a form of thalassemia involving the genes HBA1 and HBA2. Alpha-thalassemia is due to impaired production of 1,2,3, or 4 alpha globin chains, leading to a relative excess of beta globin chains...
can also cause hydrops fetalis when all four of the genetic loci for α globin are deleted or affected by mutation. This is termed Hb Barts (consists of y-4 tetramers). - Uncommonly, Niemann-Pick DiseaseNiemann-Pick diseaseNiemann–Pick disease refers to a group of fatal inherited metabolic disorders that are included in the larger family of lysosomal storage diseases .-Signs and symptoms:Symptoms are related to the organs in which they accumulate...
Type C (NPC) and Gaucher Disease type 2 can present with hydrops fetalis. - Turner SyndromeTurner syndromeTurner syndrome or Ullrich-Turner syndrome encompasses several conditions in human females, of which monosomy X is most common. It is a chromosomal abnormality in which all or part of one of the sex chromosomes is absent...
- TumorTumorA tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
s, the most common type of fetal tumor being teratomaTeratomaA teratoma is an encapsulated tumor with tissue or organ components resembling normal derivatives of all three germ layers. There are rare occasions when not all three germ layers are identifiable...
, particularly a sacrococcygeal teratomaSacrococcygeal teratomaSacrococcygeal teratoma is a teratoma located at the base of the coccyx . It is thought to be a derivative of the primitive streak.-Natural history:...
. - Twin-twin transfusion syndrome in monochorionic pregnancy (hydrops affects the recipient twin)
- Maternal hyperthyroidismHyperthyroidismHyperthyroidism is the term for overactive tissue within the thyroid gland causing an overproduction of thyroid hormones . Hyperthyroidism is thus a cause of thyrotoxicosis, the clinical condition of increased thyroid hormones in the blood. Hyperthyroidism and thyrotoxicosis are not synonymous...
Diagnosis
Hydrops fetalis can be diagnosed and monitored by ultrasoundObstetric ultrasonography
Obstetric sonography is the application of medical ultrasonography to obstetrics, in which sonography is used to visualize the embryo or foetus in its mother's uterus...
scans. Prenatal ultrasound scanning enables early recognition of hydrops fetalis and has been enhanced with the introduction of MCA Doppler.
Treatment
The treatment depends on the cause.Severely anemic fetuses can be treated with blood transfusions while still in the womb.