**6. Autosomal dominant polycystic kidney disease (Potter type III)**

Definition: ADPKD is a bilateral renal anomaly where cysts arise from all areas of the nephron or collecting ducts. It commonly appears in adults but can rarely be seen prenatally, especially when screening is targeted to families at risk.

Clinical facts:

• Risk of chromosomal anomalies (5–10%).

drome, and tuberous sclerosis.

• Perform careful follow-up.

**8. Pelvis dilatation**

• 3 mm in the first trimester.

• 7 mm after 32 weeks.

obstruction.

• 4 mm between 14 and 22 weeks. • 5 mm between 22 and 32 weeks.

• Above 10 mm always pathology.

Incidence: 1–5:500 newborns.

trimester.

• Risk of nonchromosomal syndromes may be found in VACTERL, cerebro-reno-digital syn-

Renal Anomalies

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http://dx.doi.org/10.5772/intechopen.71925

Definition: the dilatation of the pelvis is the most common anomaly detected by ultrasound. It can present as a mild pelviectasis or as hydronephrosis. Though numbers may vary in dif-

• Mild pelviectasis [2]: above 4 mm in the second trimester and above 7 mm in the third

• Hydronephrosis [4]: above 7 mm between 16 and 20 weeks and above 10 mm after 20 weeks.

Pathology: mild pelviectasis has been associated with aneuploidy (minor marker), especially trisomy 21. The mechanism for unilateral hydronephrosis may be obstruction of the ureteropelvic junction, vesicoureteral reflux, and obstruction of the vesicourethral junction. Bilateral hydronephrosis may be caused by bilateral vesicoureteral reflux or by urethral

Ultrasound findings: renal scanning reveals a dilated renal pelvis above the cutoff for the respective gestational age. Frequently, when hydronephrosis is installed, the calyces are also

• Look for renal cysts when urinary tract obstruction is diagnosed.

• Bilateral: oligoamnios + distended bladder + bilateral renal cysts.

• Amniocentesis is indicated when associated anomalies are present.

• Unilateral: renal cysts + hydronephrosis/hydroureter.

• May be impossible to differentiate from MCDK. • Termination should be offered for bilateral form.

ferent sources, generally values are around these figures:

Limits of normal size for gestational age have also been described [2]:

Incidence: 1:1000.

Pathology: the genetic mechanism involves two genes PKD1 and PKD2 on chromosome 16. The condition is associated with multiple renal cysts, hypertension, and renal failure. Cysts are also present in the liver, spleen, and pancreas.

Ultrasound findings: the kidneys are hyperechoic, in some cases only in the cortical region. Amniotic fluid and the bladder are usually normal.

Differential diagnosis: ARPKD (autosomal recessive polycystic kidney disease). Normal fluid, bladder, and family history help us make the difference.

Clinical facts:

