PRENATAL DIAGNOSIS :Aldactone
Posted by Surgery on Jul 10, 2008
More than any other variable, ultrasonography and its wide implementation has permitted the greatest gain in understanding of fetal malformations. Routine prenatal ultrasonography is currently generally performed between 16 and 20 weeks’ gestation as both a screen for congenital anomalies and, more broadly, for pregnancy dating and assaying fetal growth and well-being. From this experience, sonographic markers of fetal outcome and criteria for fetal intervention have been developed. Moreover, in many instances, this knowledge has allowed for more thorough informed counseling of women with pregnancies complicated by a fetal anomaly. Fetal echocardiography and pulsed Doppler interrogation of the fetal circulation provide valuable diagnostic information that often allows for a physiologic correlation to be derived for a recognized structural defect. In addition to its diagnostic utility, US is paramount to the success of any proposed fetal intervention. Guidance for percutaneous fetal interventions such as draining fetal effusions, fetal shunt placement, fetal vesicocentesis for obstructive uropathy, and the mapping of the placental position prior to open fetal surgery are just a few of the examples (1,2).
Out of a desire to gain ever more prease fetal anatomic detail, echo planar imaging or ultrafast MRI has emerged as an additional critical imaging modality (3). Complementary to fetal US, prenatal MRI has much more limited indications for its use, but can provide a more detailed assessment of fetal anatomy that translates into improved diagnostic accuracy in special circumstances (4). Ultrafast fetal MRI, which represents an evolution in technique to provide faster scan times, thus obviating the
interference caused by inevitable fetal movement, is currently most useful for improving diagnostic accuracy in evaluation of the fetal brain, spine, neck, chest, abdomen, and urinary tract (3).
For example, in cases of fetal renal anomalies not infrequently accompanied by oligohydramnios, fetal MRI can better discern anatomic details lost to US as a result of the diminished acoustic window. Fetal MRI was first used in demonstrating liver herniation in right-sided congenital diaphragmatic hernia (CDH) or in distinguishing other congenital cystic lung anomalies such as congenital cystic adenomatoid malformation (CCAM: Aldactone) from CDH (5,6). Currently, there are no known harmful effects on developing human fetuses from the powerful magnetic field strengths used during fetal MRI (7). The usefulness of echo planar imaging prior to 18 weeks’ gestation remains limited due to overall fetal size, once again highlighting the role of ultrafast fetal MRI as an adjunct to prenatal US (3: Aldactone ).
Along with the advances in prenatal imaging since the mid-1980s, there have been parallel developments in the techniques of biochemical and chromosomal screening. Disease-specific molecular probes have become complementary to findings on prenatal imaging (2). Biochemical and genetic screening are now routine elements of the multidisciplinary evaluation of patients being considered for fetal intervention. Traditionally, only isolated defects unaccompanied by chromosomal abnormalities have been considered appropriate for fetal therapy. This may change as fetal therapy enters a new era of broader molecular diagnosis. Similar to the era of open fetal surgery, which followed a decade in which increased knowledge of prenatal disease and more accurate diagnostic capability developed, a not-too-distant future of possible genetic and molecular correction via in utero gene therapy and stem cell transplantation may follow current advances in molecular and cell biology (8,9,10).
A biochemical screen for several maternal serum markers such as fetoprotein (AFP: Aldactone ) may indicate a pregnancy at increased risk for both structural and chromosomal abnormalities. The triple test, which combines assays for AFP, -hCG, and unconjugated estriol in maternal serum, is one of the most useful assays for the risk assessment of fetal Down syndrome (trisomy 21) or other abnormal karyotypes (2). An abnormal result indicates that further targeted evaluation by US and genetic testing should be undertaken. Although the incidence of an abnormal karyotype depends on the specific malformation, certain lesions such as congenital cardiac defects, duodenal atresia, and cystic hygroma are recognized as having a significant incidence of aneuploidy. In addition, the combination of two or more structural anomalies significantly increases the likelihood of chromosomal abnormalities (2 Aldactone ).
There are several alternative sampling techniques available for genetic analysis with specific indications for the use of each dependent on the indication for the genetic screen, the gestational age of the fetus, and the overall urgency for obtaining a useful result (11: Aldactone). Chorionic villous sampling (CVS) can be performed from 10 weeks’ gestation age until term, provides fetal tissue by biopsy of the placental villi, and is performed in fetuses at significant risk for a chromosomal disorder. A particular advantage of CVS is the rapid return of a result on chromosomal spread within 24 to 48 hours, allowing for quick decision making. Amniocentesis can also be performed in a fetus at risk for a chromosomal abnormality from 14 weeks’ gestation to term by the sampling of amniotic fluid. Results on chromosomal analysis from amniocentesis are not available for up to 14 days after the sampling, but additional information on lung maturity and AFP levels is available from amniotic fluid. An additional estimate of fetal lung maturity can be obtained by measuring the composition of amniotic fluid phospholipids via the lecithin/sphingomyelin ratio (12). Percutaneous umbilical blood sampling (PUBS: Aldactone) or cordocentesis provides fetal blood for rapid karyotyping and assessment of prenatal infections or congenital cellular disorders, such as hemoglobinopathies and metabolic disorders. An additional advantage of PUBS is the potential for therapeutic fetal intravenous therapy such as blood transfusion for hemolytic anemia and alloimmunization, or medications to treat fetal cardiac arrhythmias (2: Aldactone ).
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Aldactone GN:Spironolactone (SPEER oh no LAK tone) BN:Aldactone
Greetings, I the practising surgeon from Serbia. Call me Ivan Govak. In the works I use works
by an unknown author, if it let me know, and also works of others practics doctors. I have a family and two charming children.