HYDROPS FETALIS CARDIAC CAUSES
Category: Child Health
Abstract : hydrops fetalis cardiac causes • Congenital structural anomalies of the heart may accompany as many as 1 in 4 babies with hydrops; both right-heart and left-heart anomalies, systolic-overload and diastolic-overload conditions, high-output, and congestive situations are represented. o Structural cardiac defects are commonly accompanied by other anomalies and often are associated with c
hydrops fetalis cardiac causes
• Congenital structural anomalies of the heart may accompany as many as 1 in 4 babies with hydrops; both right-heart and left-heart anomalies, systolic-overload and diastolic-overload conditions, high-output, and congestive situations are represented.
o Structural cardiac defects are commonly accompanied by other anomalies and often are associated with cytogenic abnormalities.
Examples include the association between coarctation of the aorta and Turner syndrome, the relation between atrioventricular (AV) canal and/or endocardial cushion defects and Down syndrome, and the common association of Turner syndrome with cystic hygroma, left-sided lymphatic flow defects, and left-heart outflow defects.
o Fibroelastosis may be an isolated abnormality; however, fibroelastosis more commonly represents an endocardial response to chronic fetal myocardial stress. Prenatal detection of a cardiac defect should always trigger a careful search for other malformations, and karyotyping should be performed in all such fetuses. Arteriovenous malformations (AVMs) are often cited causes of hydrops.
• Impaired right-heart filling is also an important cause of hydrops. Although uncommon, umbilical or vena caval thromboses are noted, since they theoretically may be correctable if diagnosed early enough. Conversely, tumor compression is a frequently reported cause of hydrops. Several of these masses involve lymphatic malformation and/or obstruction; cystic hygroma is a particularly important example.
• Prenatal closure of the foramen ovale or ductus arteriosus prematurely converts the (parallel) fetal circulation to a (serial) postnatal circulation; associated problems are obvious.
o Most recorded instances of premature ductal closure are iatrogenic, related to maternal administration of indomethacin or sodium diclofenac.
o Several instances of idiopathic arterial calcification with hydrops have been reported. In one such incident, fetal serum calcium levels were elevated, and a possible association with Williams syndrome was suggested. In 3 other cases, lysosomal storage diseases were present (Gaucher, sialidosis, galactosialidosis). No associations were noted in 4 cases. Hydropic recipients of twin-twin transfusion who survive usually also have pulmonary artery calcification.
• Fetal supraventricular tachycardias are important causes of hydrops because they can be diagnosed accurately by cardiac imaging in early pregnancy, they may be treated effectively before hydrops develops, and, since associated malformations or syndromes are rare, they have anticipated good outcomes. Whether an AV block is present (atrial flutter) or not (tachyarrhythmia), survival rates of 85-95% are typical, and neurodevelopmental outcome usually is normal. The condition is more common in males than in females (2:1), and hypoglycemia is a commonly associated finding, at least after birth. Clinical experience and animal model studies indicate that hydrops occurs with sustained cardiac rates of less than 220-230 beats per minute (bpm) and that the risk is related directly to the degree of prematurity.
• Congenital heart block (CHB) is also often associated with hydrops. Diagnosis is made using cardiac imaging; rates are always less than 90 bpm and usually less than 65 bpm. Approximately two thirds to three fourths occur in pregnancies complicated by maternal collagen disease. Maternal IgG antinuclear antibodies cross the placenta and attack fetal collagen in the conduction bundle.
o Why some fetuses develop CHB and some do not is unclear; however, an association with human leukocyte antigen (HLA) types (HLA-DR3, among others) has been suggested.
o Treatment with a variety of drugs has generally been unsuccessful, as has fetal surgery for pacing. Recent evidence suggests corticosteroid therapy may be of benefit.
• Virtually all of the remaining babies, whose mothers have no collagen disorder, have serious, complicated, cardiac structural defects. The most common lesions are AV canal and/or endocardial cushion defects, transposition of the great vessels, and other isomerisms. Outcomes for these babies are grim. Mortality is 25-35% if cardiac structure is normal; many survivors require neonatal surgery for pacing, and no information is available on long-term outlooks. Since the cardiac structural abnormalities are so serious and complex, mortality and morbidity are much higher if cardiac anomalies are present.
Hit: 314 times
Related Articles in Child Health :
|
Advertise with Health Information Encyclopedia