Pyelectasis is a dilation of the

renal pelvis The renal pelvis or pelvis of the kidney is the funnel-like dilated part of the ureter in the kidney. It is formed by the covnvergence of the major calyces, acting as a funnel for urine flowing from the major calyces to the ureter. It has a mucous ...

. It is a relatively common

ultrasound Ultrasound is sound waves with frequency, frequencies higher than the upper audible limit of human hearing range, hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hea ...

finding in

fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal deve ...

es and is three times more common in male fetuses. In most cases pyelectasis resolves normally, having no ill effects on the baby. The significance of pyelectasis in fetuses is not clear. It was thought to be a marker for obstruction, but in most cases it resolves spontaneously. In some studies it has been shown to appear and disappear several times throughout the course of pregnancy. There is some discussion about what degree of pyelectasis is considered severe enough to warrant further investigation and most authorities use 6mm as the cut-off point. Pyelectasis is considered to be a "soft marker” for

Down syndrome Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays, mild to moderate intellectual dis ...

. This, along with other factors such as age and abnormal maternal serum screening (exa, Integrated or Quad screen), may be grounds for a prenatal diagnostic test such as an

amniocentesis Amniocentesis is a medical procedure used primarily in the prenatal diagnosis of genetic conditions. It has other uses such as in the assessment of infection and fetal lung maturity. Prenatal diagnostic testing, which includes amniocentesis, is ne ...

to rule out Down syndrome. Babies with unresolved pyelectasis may experience

urological Urology (from Greek οὖρον ''ouron'' "urine" and ''-logia'' "study of"), also known as genitourinary surgery, is the branch of medicine that focuses on surgical and medical diseases of the urinary-tract system and the reproductive organ ...

problems requiring surgery.

Etymology and pronunciation

The word ''pyelectasis'' () is derived from the prefix ''

pyelo- The renal pelvis or pelvis of the kidney is the funnel-like dilated part of the ureter in the kidney. It is formed by the covnvergence of the major calyces, acting as a funnel for urine flowing from the major calyces to the ureter. It has a mucous ...

'', meaning " enalpelvis", and ''

ectasis Ectasia (), also called ectasis (), is dilation or distention of a tubular structure, either normal or Pathophysiology, pathophysiologic but usually the latter (except in atelectasis, where absence of ectasis is the problem). Specific conditions * ...

'', meaning "dilation or distension".

External links

OBfocus.com

The Fetus.net

The Harvey Institute for Human Genetics

Radiopedia article
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