SON 2122 Obstetrical Sonography Part II Chapter 16 The fetal Genitourinary tract HHHoldorf

Outline Bladder Outlet Obstruction Posterior Urethral Valves Normal Fetal Genitourinary System Normal Fetal kidneys Normal fetal bladder Normal fetal adrenal glands Genitalia Renal Anomalies Renal Agenesis Polycystic Kidney Disease Multicystic Dysplastic Kidney Disease Solid Renal Masses Neuroblastoma (Wilm’s Tumor) Ureterovescial Pathology UPJ Obstruction Bladder Outlet Obstruction Posterior Urethral Valves Urethral Atresia Cloacal Malformation Prune Belly Syndrome Female genital Tract Ovarian cysts Hydrometrocolopos

The normal GU system

Normal Anatomy   Kidneys Originate in the pelvis and migrate superiorly during gestation. Can be seen as early as 12-14 weeks Renal pyramids are echo-poor Renal sinus fat is more echogenic and can be seen in the hilum of each kidney. Occasionally the renal pelvis may contain small amounts of fluid

Age-related renal pelvis measurements (AP) Weeks 13-20 5mm Weeks 20-30 8mm Weeks 30-term 10mm

AP Renal Pelvis measurements Less than or equal to 5mm is normal 5-10mm is probably normal. Should have a follow-up Greater than or equal to 10mm: 85% have anatomic anomaly

Normal fetal kidneys-Transverse

Normal fetal kidney-sagittal

Can been seen at about 20 weeks Indicator or active renal function Bladder Can been seen at about 20 weeks Indicator or active renal function Empties and fills normally in 30-45 minute cycles If it’s not seen, don’t panic. Re-scan in 20/30 minutes. Then if you don’t see it, panic.  

Fetal bladder with umbilical arteries

Normal fetal bladder

Adrenal Glands Large in the fetus. 90% is cortex Seen as oval masses of echo-poor tissue lying superior to the kidneys on the Sagittal scan Transversely, they appear long, thin and echogenic in the medulla and are surrounded by thicker sonolucent rims of cortex They should be smaller than the normal kidney.

transverse normal adrenal gland

Sagittal normal adrenal gland

Genitalia The determination of the gender of a fetus may assist in the differential diagnosis of GU anomalies and or chromosomal syndromes

Male genitalia

Female genitalia

RENAL ANOMALIES Renal agenesis The congenital absence of one or both kidneys Unilateral-very common and causes no symptoms Bilateral (Potter’s syndrome) Bilateral renal agenesis (BRA) Pulmonary hypoplasia Facial anomalies Patients present as small for dates

BRA Associated with other stuff Cardiovascular disease Gastrointestinal disease Skeletal and GU anomalies Sonographic findings of BRA Severe Oligohydramnios seen between 16-28 weeks is not a good finding Absent kidneys with “lying down” adrenal glands within the renal fossa (don’t mistake them for kidneys) Bladder not extended

Bilateral renal agenesis

Bilateral renal agenesis

Unilateral renal agenesis

Unilateral renal agenesis

Polycystic Kidney Disease Inherited disorder characterized by many bilateral cysts. Cysts cause enlargement of the total renal size while reducing the functioning renal tissue. Autosomal – recessive type (ARPKD) is diagnosed in utero.

ADPKD vs. ARPKD: What is the Difference? Autosomal dominant (ADPKD) is one of the most common life-threatening genetic diseases. ADPKD affects approximately 1 in 500. It does not skip a generation. There is usually a family history of ADPKD. Parents with ADPKD have a 50 percent change of passing the disease on to each of their children. Autosomal recessive (ARPKD) is a relatively rare genetic disorder, occurring in approximately 1 in 20,000 individuals. It affects boys and girls equally and often causes significant mortality in the first month of life.

FOUR TYPES OF PKD Perinatal-renal failure occurs in utero Neonatal occurs within first month after birth; death within 1 year Infantile- occurs by 3-6 months of age, with 20% renal involvement. Hepatosplenomegaly. It progresses to renal failure Juvenile – appears at 1-5 years of age. Less renal involvement, but same result as infantile group.

Sonographic findings Large kidneys-hyper echoic Increased kidney to AC ratio Bladder is usually small Loss of cortico – medullary differentiation Kidneys may appear normal in early pregnancy

Polycystic kidney disease 31st week of pregnancy; parasagittal scan at the level of the fetal kidneys show their hyperechoic appearance. Oligohydramnios was also present.

Polycystic kidney disease

Multicystic Dysplastic Kidney Obstruction of the kidney during its development leads to formation of cysts which replace renal parenchyma. MCDK is non-functioning Cysts can be large, up to 6 cm Cysts may be unilateral. Cannot be detected EARLY in gestation…cysts are too small

Sonographic findings If Bilateral -multiple, randomly located variable sized cysts -cannot see fetal bladder when renal insufficiency is present -Oligohydramnios possible

If Unilateral Multiple cysts in one kidney Normal contra-lateral kidney Bladder seen if “good” kidney is sufficiently operating

mcdc

Mcdk-bilateral

MCDK

MCDK

Solid Renal Masses Several types are possible, though rare Mesoblasitc nephroma Adrenal neuroblastoma Sonographic findings Presence of a solid mass in the renal fossa

Neonatal Adrenal mass-Neuroblastoma

Nephroblastoma A.K.A. Wilms tumor Neruoblastoma: A cancer that is commonly found in the adrenal glands. Nephroblastoma: Also called Wilm’s tumor, is a mass of cancer cells that grow in the kidney tissue.

Fetal Adrenal Neuroblastoma

Fetal nephroblastoma: Wilms’ tumor

Obstructive Uropathy May vary in location Bilateral obstructions may lead to renal dysplasia, renal failure, and death

Uretropelvic Junction Obstruction UPJ obstruction is the most common cause of neonatal Hydronephrosis There is an obstruction of urine flow from the renal pelvis to the ureter. Causes: fibrous adhesions, kinks, ureteral valves. Amniotic fluid volume is usually normal.

UPJ OBSTRUCTION in utero

Sonographic findings of a UPJ Demonstration of a dilated renal pelvis Thinning of the renal cortex in chronic states  

UPJ obstruction

Bladder Outlet Obstructions Most BOBs occur in male fetuses. Posterior Urethral valves are most common cause. In females, cloacal malformations or urethral atresia are usually the cause.

PUV Congenital folds of the urethra act as valves and obstruct urinary outflow. PUVs can cause severe damage to the kidneys, ureters and bladder.

Sonographic findings Marked bilateral Hydronephrosis and dilated, tortuous ureters Bladder wall thickening “keyhole” appearance of bladder-referring to dilated bladder and prostatic urethra Moderate to profound Oligohydramnios Male genitalia identified

PUV – Keyhole sign

Bilateral hydronephrosis from PUV

Urethral Atresia Can occur in both sexes Complete obstruction due to absence of the urethra Not compatible with life No amniotic fluid after 16 weeks and pulmonary hypoplasia is certain  

Cloacal Malformation Rare Convergence of the GI and GU tracts Single opening in the perineum, which empties in both systems Severe obstruction with Oligohydramnios. Poor prognosis

Defined as confluence of rectum, vagina and urethra into a single common chamber that opens into a single orifice where the normal urethral opening is located

Cloacal malformation: 32 weeks -evaluation of a fetal cystic mass lesion in abdomen. Three cystic masses in lower abdomen with ascites were observed.  Amniotic fluid was normal. The bladder was not identified. Cloacal malformation was suspected. Post natal examination confirmed the diagnosis.

Persistent cloaca

Complex/Persistent Cloaca Only in females High incidence in Chinese girls Seems to be part of the VACTERL syndrome V Vertebral A anorectal C Cardiac T Trachea-esophageal R Renal L Limb

Prune Belly Syndrome Massive early dilation of the urinary bladder causes pressure atrophy of the abdominal wall Most common cause is PUVs. Decompression of Hydronephrosis post-natally causes retraction and wrinkling of the anterior abdominal wall skin, Giving the appearance of a prune. Associated with pulmonary hypoplasia and severe Oligohydramnios

Sonographic findings Abnormal compression of abdominal wall by fetal small parts Movement of fetal abdominal wall when maternal abdomen is tapped firmly. Oligohydramnios Bilateral Hydronephrosis and massively distended urinary bladder

Prune belly syndrome

Prune belly syndrome

Fetal Genital Tact Males Undescended testes-normally descend into the scrotum between 26 and 34 weeks gestation Hydroceles-small hydroceles are common. Large ones warrant postnatal follow-up Abnormal formation of the penis   Females Hydrometrocolopos Ovarian cysts

Hydrometrocolopos A collection of watery fluid in the uterus and vagina Caused by vaginal atresia

Hydrometrocolopos

Ovarian cyst-in utero