*2.3.10. Multicystic kidney disease*

It is a congenital disorder characterized by cystic lesions that correspond primarily to dilated collecting tubules. The disease can be bilateral, unilateral, or segmental and it is known also as Potter's type II syndrome, cystic kidney disease, and multicystic dysplastic kidneys.

It can be isolated or associated with urinary or extraurinary disorders such as: malrotations, ureteropelvic junction obstruction, horseshoe kidney, cardiovascular malformations, CNS abnormalities (anencephaly, hydrocephalus, iniencephaly, spina bifida, occipital meningocele), diaphragmatic hernia, cleft palate, microphthalmia, duodenal stenosis and imperforate anus, esotracheal fistula, and bilateral absence of radius and thumb. Association with liver cysts or pancreatic cysts is not characteristic for Potter II syndrome [24].

Ultrasound diagnosis of multicystic kidneys (**Figure 11**) is made in the presence of an enlarged unilateral or bilateral kidney with multiple round anechoic structures peripheral located and variable in size. In some cases, the kidneys can be small but the renal sinus cannot be identified. Oligohydramnios is a common association, but in some cases, when the lesion is unilateral or the obstruction is incomplete, amniotic fluid may have normal volume.

Differential diagnosis includes infantile polycystic kidney disease, single cyst, ureteropelvic junction obstruction, Wilms tumor and hamartoma that has undergone necrosis, but can be difficult to diagnose prenatally.

The prognosis of bilateral disease is poor and termination of pregnancy can be offered. Unilateral isolated disease prognosis can be favorable, but delivery should take place in a tertiary unit (**Figures 13** and **14**).

#### *2.3.11. Autosomal dominant polycystic kidney disease (ADPKD)*

**Figure 10.** Ovarian cyst—two anechoic round structures in the fetal pelvis with no Doppler signal.

with anechoic abdominal masses [22].

262 Congenital Anomalies - From the Embryo to the Neonate

the postsurgery mortality is absent [23].

nal birth is preferred (**Figures 11** and **12**).

Ultrasound diagnosis is based on the evidence of the dilated renal pelvis and on the measurement of the anteroposterior diameter of the dilatation on transverse abdominal section. Former criteria of hydronephrosis dilatation included also the ratio between the maximum transverse pelvic diameter and the renal diameter at the same level with ratios above 50% being the cut-off for hydronephrosis. Most UPJ obstructions are unilateral and bladder should fill normally. In case of severe oligohydramnios, association of unilateral hydronephrosis contralateral renal agenesis or dysplasia should be suspected. Differential diagnosis includes multicystic dysplastic kidneys, polycystic kidneys, and other condition associated

**Figure 9.** Intestinal obstruction—small bowel dilatations above the obstruction level.

The prognosis of ureteropelvic obstruction is generally good, but requires serial ultrasound scans to evaluate the progress of the dilatation. In most cases, the surgery is not needed, but

Concerning the prenatal management, there is no need for premature intervention and vagi-

Adult polycystic kidney disease (APKD) is an autosomal dominant condition characterized by the presence of multiple cysts of variable size in the renal parenchyma. The cysts can replace the parenchyma and are produced by the dilatation of the collecting tubules and other tubular segments

**Figure 11.** Hydronephrosis—significant dilatation of the renal pelvis and reduced thickens of the renal functional tissue.

**Figure 12.** Ureteral dilatation consecutive to uretro-vesical obstruction.

of the nephrons. Potter's type III polycystic is one of the entities responsible for ADPKD in which cysts of variable sizes (some up to several centimeters) coexists with normal renal structure. Being an autosomal dominant disease, the risk of transmission to the off springs of the altered gene on chromosome 16 is 1/2 pregnancies. APKD is one of the most common genetic disorders and the third most prevalent cause of chronic renal failure [25]. Epigenetic factors and penetrance of the gene determine the variability in symptoms, the disease manifesting late in the fourth decade. Intrauterine manifestation of the disease is not uncommon [26]. APKD is associated with cysts affecting other organs: liver, pancreas, spleen, lungs, testes, ovaries, and epididymis.

The prognosis depends on other associated anomalies. The parents must be informed that the immediate outcome can be good, but the natural history of the disease includes the following: from completely asymptomatic to lower abdominal pain, renal enlargement, renal insufficiency, uremia and hypertension, with a mean age of onset of symptoms in the fourth decade of life.

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Obstetrical management is based on the gestational age at diagnosis; in the first trimester, pregnancy termination can be offered. Family members should undergo ultrasound examination as well. The fetus must be thoroughly scanned to exclude other anomalies. Otherwise, the

Infantile polycystic kidney disease (IPKD) is an autosomal recessive disorder characterized by bilateral and symmetrical enlargement of the kidneys. The disease is known also as polycystic kidney disease type I, infantile polycystic disease of the liver and kidney. Unlike the adult polycystic kidney disease, there is no renal parenchyma, only dilated collecting tubules [27]. As a recessive autosomal inherited condition, the risk of transmission is 25%. The disease is always bilateral. Other anomalies that can be associated: liver cysts, biliary duct hyperplasia,

obstetrical attitude is not altered and vaginal birth is the first choice (**Figure 15**).

*2.3.12. Infantile polycystic kidney disease*

**Figure 15.** Autosomal polycystic kidney disease.

**Figure 14.** Giant kidney cyst.

and dilatation of the biliary tree and portal hypertension.

Prenatal diagnosis is difficult and often late due to the nonspecific appearance of the kidneys; only a few of these diagnoses can be recognized in the prenatal period, by family history, amniotic fluid volume, associated abnormalities, and genetic testing [4].

Ultrasound diagnosis of the APKD can be suspected in the presence of moderately enlarged hyperechogenic kidneys, with increased corticomedullary differentiation (CMD), in association with a normal amount of amniotic fluid. The diagnosis is usually late and should prompt investigation of both parents.

**Figure 13.** Multicystic kidney—multiple anechoic round structures occupying the whole renal aria with no remaining normal renal structure.

**Figure 14.** Giant kidney cyst.

The prognosis depends on other associated anomalies. The parents must be informed that the immediate outcome can be good, but the natural history of the disease includes the following: from completely asymptomatic to lower abdominal pain, renal enlargement, renal insufficiency, uremia and hypertension, with a mean age of onset of symptoms in the fourth decade of life.

Obstetrical management is based on the gestational age at diagnosis; in the first trimester, pregnancy termination can be offered. Family members should undergo ultrasound examination as well. The fetus must be thoroughly scanned to exclude other anomalies. Otherwise, the obstetrical attitude is not altered and vaginal birth is the first choice (**Figure 15**).

### *2.3.12. Infantile polycystic kidney disease*

Infantile polycystic kidney disease (IPKD) is an autosomal recessive disorder characterized by bilateral and symmetrical enlargement of the kidneys. The disease is known also as polycystic kidney disease type I, infantile polycystic disease of the liver and kidney. Unlike the adult polycystic kidney disease, there is no renal parenchyma, only dilated collecting tubules [27]. As a recessive autosomal inherited condition, the risk of transmission is 25%. The disease is always bilateral. Other anomalies that can be associated: liver cysts, biliary duct hyperplasia, and dilatation of the biliary tree and portal hypertension.

**Figure 15.** Autosomal polycystic kidney disease.

**Figure 13.** Multicystic kidney—multiple anechoic round structures occupying the whole renal aria with no remaining

of the nephrons. Potter's type III polycystic is one of the entities responsible for ADPKD in which cysts of variable sizes (some up to several centimeters) coexists with normal renal structure. Being an autosomal dominant disease, the risk of transmission to the off springs of the altered gene on chromosome 16 is 1/2 pregnancies. APKD is one of the most common genetic disorders and the third most prevalent cause of chronic renal failure [25]. Epigenetic factors and penetrance of the gene determine the variability in symptoms, the disease manifesting late in the fourth decade. Intrauterine manifestation of the disease is not uncommon [26]. APKD is associated with cysts

Prenatal diagnosis is difficult and often late due to the nonspecific appearance of the kidneys; only a few of these diagnoses can be recognized in the prenatal period, by family history,

Ultrasound diagnosis of the APKD can be suspected in the presence of moderately enlarged hyperechogenic kidneys, with increased corticomedullary differentiation (CMD), in association with a normal amount of amniotic fluid. The diagnosis is usually late and should prompt

affecting other organs: liver, pancreas, spleen, lungs, testes, ovaries, and epididymis.

amniotic fluid volume, associated abnormalities, and genetic testing [4].

**Figure 12.** Ureteral dilatation consecutive to uretro-vesical obstruction.

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normal renal structure.

investigation of both parents.

Ultrasound diagnosis is based on three elements:


The disease can be diagnosed late in pregnancy or may progress gradually during pregnancy; therefore, repeated scans are mandatory.

Ultrasound diagnosis can be made in the presence of megacystis, hydroureter, and hydronephrosis in a male infant. In female fetus, lower urinary tract obstruction includes agenesis of the urethra, megacystis-microcolon-intestinal hypoperistalsis syndrome, and variants of the caudal regression syndrome. When the rupture of the megacystis intervenes, urine can

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The differential diagnosis is difficult in prenatal life, and includes ureteropelvic junction obstruction, ureterovesical junction obstruction, primary megaureter, and massive vesicoure-

Prognosis depends on the renal reserve, which can be difficult to assess prenatally. Another factor that can influence the outcome is the timing of the occurrence of urinary obstruction, and this is a critical factor: the earlier its appearance–the worse the prognosis. Complications include: pneumomediastinum and pneumothorax, related to pulmonary hypoplasia, associated congenital anomalies, renal failure, and surgical complications after decompressive surgery. Termination of pregnancy can be offered if the prognosis is poor and if other anomalies are associated. In utero vesicoamniotic shunts are possible, but the results at 2 years of life are not very encouraging [31].

Intestinal perforation in fetuses during pregnancy can lead to a sterile, chemical, and localized type of peritonitis. At the site of the perforation, a reactive process of calcification and fibrosis occurs in order to stop the progression. The etiology is in over 50% of cases due to intestinal stenosis, atresia, or meconium ileus. Other cited situations are volvulus or Meckel's diverticulitis. Meconium ileus is associated with cystic fibrosis and results from the blockage

The diagnosis is suggested by the dilatation of the intestinal loops or the presence of hyperechoic areas situated in the abdomen of the fetus. Over 80% of the fetuses that developed meconium peritonitis also have intra-abdominal calcifications. Ascites is an important sign of intestinal peritonitis. Other ultrasonographic signs suggesting meconium peritonitis include: polyhydramnios, meconial pseudocysts, thickening of the abdominal wall or pleural effusions. The differential diagnosis of hyperechoic abdominal masses include: intra-amniotic hemor-

Meconium ileus and hyperechoic images of the intestinal loops at 16–18 weeks of gestation can be present in over 75% of cystic fibrosis affected fetuses. The incidence of cystic fibrosis in fetuses diagnosed before birth with intestinal obstruction is approximately 10%, consequently when other causes of intestinal blockage have been excluded, a genetic cystic fibrosis test is recommended.

The prognosis is poor in this case; approximately, 50% of fetuses suffering from meconium

Most of them are idiopathic, but can be associated with congenital infections and chromosomal anomalies. The incidence rate is 1:2000 fetuses, especially in the 3rd trimester. The

of the distal ileum with compacted meconium. The incidence is 1:3000 births.

rhage, early ascites, fetal hypoxia, meconium peritonitis, and cystic fibrosis.

peritonitis pass away in the neonatal period.

*2.3.16. Liver calcifications*

extravasate into the peritoneal cavity. Oligohydramnios can also occur.

teral reflux, absence of the urethra or detrusor hypertrophy.

*2.3.15. Meconium peritonitis*

The prognosis depends on the clinical variety of IPKD, which can vary from mild to severe with intrauterine death. After birth, the most important complications are respiratory, as a consequence of the pulmonary hypoplasia. Death later in life is the result of renal failure.

The management depends on the diagnosis age; if the diagnosis is made before viability, termination of pregnancy should be offered to the parents. Also in cases with severe oligohydramnios and absent bladder, the termination of pregnancy can be offered even in the third trimester.
