What ultrasound finding after 24 weeks' gestat - resi_hopeful
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What ultrasound finding after 24 weeks' gestat - resi_hopeful
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08-16-2014, 11:14 AM
What ultrasound finding after 24 weeks' gestation is most often associated with Down's syndrome?
A.Cardiac defects B.Echogenic cardiac focus C.Pyelectasis D.Sandal gap toe E.Thickened nuchal fold We value your feedback!
08-16-2014, 12:34 PM
The correct answer is A. 47% chose this.
An advanced-level ultrasound can detect many abnormal anatomic defects. Several of these defects are associated with trisomy 21. However, most findings are considered "soft markers" and are frequently found in normal fetuses. The most frequent abnormality found in trisomy 21 is cardiac defects, and they occur in approximately 40% of infants with trisomy 21. The most common defects include endocardial cushion defects and ventricular septal defects. B is not correct. 7% chose this. About 20%-30% of trisomy 21 fetuses have an echogenic cardiac focus, and only 4% of normal fetuses have it. If this is an isolated finding, it does not confer an increased risk of trisomy 21. C is not correct. 2% chose this. Pyelectasis is a soft marker of trisomy 21. However, it is frequently seen in normal fetuses and does not have a high positive predictive value in detecting trisomy 21. D is not correct. 4% chose this. Sandal gap toe is a soft marker of trisomy 21. However, it is frequently seen in normal fetuses and does not have a high positive predictive value in detecting trisomy 21. E is not correct. 40% chose this. A thickened nuchal fold is most sensitive at 10-14 weeks' gestation (70%-80% sensitivity), and decreases to 40%-50% at 15-20 weeks' gestation. It may be normal on an anatomy scan performed at 24 weeks or later. |
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