Fetal Genitourinary Tract

Question 1

Kidneys originate in the embryonic pelvis and migrate ____ during the ____ week of gestation.

Answer 1

superiorly; 13th

Question 2

The fetal kidney scan be visualized by US as early as ___ weeks as hypoechoic structures ___ to the spine in transverse images.

Answer 2

14 weeks; adjacent

Question 3

The fetal kidneys ascend from the pelvis at the same time the paired ___ ducts descend into the pelvis. (This is why these duct anomalies and renal anomalies go hand in hand.)

Answer 3

Mullerian

Question 4

Is it normal to see fluid in the fetal renal pelvis?

Answer 4

It is a normal finding seen after 24 weeks gestation.

Question 5

If the renal pelvis is greater than ___ mm AP diameter, a follow up US will be recommended.

Answer 5

7

Question 6

Fetal ureters, just like Fallopian tubes (will,will not) be seen on US unless they are obstructed.

Answer 6

will not

Question 7

The fetal urinary bladder is routinely seen by __ weeks.

Answer 7

16

Question 8

The presence of the bladder is important as it shows ___ function. It should fill and empty every ____ minutes.

Answer 8

renal; 20-30

Question 9

If you do not see the bladder, ____ in 30 minutes.

Answer 9

rescan

Question 10

The adrenal glands are _____ in a fetus. They are ___ shaped.

Answer 10

large; comma

Question 11

The adrenal glands must be differentiated in a fetus so as to not overlook __ __.

Answer 11

renal agenesis.

Question 12

The determination of ___ ___ is only important in cases of differential diagnosis in cases of GI tract anomalies and chromosomal abnormalities.

Answer 12

fetal gender

Question 13

What is oligohydraminos?

Answer 13

abnormally decreased amount of amniotic fluid

Question 14

Many renal anomalies are associated with ___.

Answer 14

oligohydraminos

Question 15

Why is AFI important to measure?

Answer 15

The amount of amniotic fluid measured is proportional to the level of fetal kidney function.
Fetal urine production is the main contributor to amniotic fluid.

Question 16

What is renal agenesis?

Answer 16

The congenital absence of one or both kidneys.

Question 17

Unilateral renal agenesis is ___, happening in about __ out of 1000 births. It is usually ___ since the other kidney just takes over all function.

Answer 17

common; 1; asymptomatic

Question 18

There is an association between ___ __ __ and a two-vessel cord. You MUST know this!

Answer 18

unilateral renal agenesis

Question 19

Bilateral renal agenesis is associated with ___ syndrome.

Answer 19

Potter’s syndrome-

1) bilateral renal agenesis
2) pulmonary hypoplasia (lack of fluid!)
3) limb deformities (secondary to lack of fluid!)
4) abnormal face (secondary to lack of fluid!)

Question 20

Sonographic findings of renal agenesis are:

Answer 20

You will not see kidneys or bladder; oligohydraminos (Make sure that you do not mistake the adrenals for kidneys!)

Question 21

There are two forms of Potter’s syndrome. Name type 1 and describe.

Answer 21

1) ARPKD Autosomal Recessive Polycystic Kidney Disease– inherited disorder, symmetric enlargement of bilateral kidneys, multiple small cysts responsible for the enlargement, oligohydraminos, small bladder (Don’t be surprised if the kidneys once appeared normal at 14-16 weeks.)

Question 22

There are two forms of Potter’s syndrome. Name type 2 and describe.

Answer 22

MCDK Multi Cystic Dysplastic Kidney– in utero developmental disorder, formation of cysts instead of normal renal parenchyma, cysts can be up to 6mm and can be uni- bi- or segmental, oligohydraminos, small to nonexistant visualization of bladder

Question 23

___ or spontaneously resolving urinary obstructions are rarely associated with any clinical abnormality.

Answer 23

Unilateral

Question 24

____ obstructions, if undetected and untreated, can lead to renal dysplasia, renal failure, or fetal death.

Answer 24

Bilateral

Question 25

What is the most common cause of fetal hydronephrosis?

Answer 25

UPJ (Ureteropelvic) obstruction. Congenital. This is the portion of the urinary tract where the proximal ureter meets the renal pelvis. More often in males. This is a FUNCTIONAL obstruction, meaning the proximal ureter doesn’t transmit urine from the kidney to the ureter efficiently. Amniotic fluid is usually normal.

Question 26

What are some causes of UPJ obstruction? If bilateral and severe this obstruction presents how on US?

Answer 26

fibrous bands, valves or kinks, anomalous vessels;

dilated renal pelvis, thinning of renal cortex, but NOT obstructed ureters

Question 27

What is a duplicated collecting system?

Answer 27

More common in females. Duplication is when two urinary collecting systems are present instead of one. They can range from two collecting systems within the renal pelvis to having two distinct ureters. There can also be a partial duplication which is when two ureters may join as one.

Question 28

What is a ureterocele?

Answer 28

If a ureteral duplication is present, the upper pole ureter will insert ectopically into the bladder, causing a herniation within the bladder. It presents on US as a thin walled cyst.

Question 29

What is megaloureter? How would it appear on US?

Answer 29

• a congenitally dilated, unobstructed ureter;
• a tortuous, long, cystic abdominal mass.
• In the fetus, bladder and amniotic fluid would be normal.

Question 30

What is the most common form of congenital or obstructive megaloureter?

Answer 30

UVJ Urterovesico junction obstruction- UNCOMMON; an obstruction at the level of the distal ureter and the bladder

Question 31

What is a posterior urethral valve?

Answer 31

MALES ONLY- KEYHOLE SIGN- congenital folds of the urethra acting as valves to obstruct flow out of the bladder. US shows distended bladder and prosthetic urethra, moderate to profound oligohydraminos, bladder wall thickening.

Question 32

What is urethral atresia?

Answer 32

Complete obstruction of the bladder due to not having a urethra. NOT COMPATIBLE WITH LIFE, fetal lungs fail to develop. US shows bilateral ureteral dilation and severe hydro

Question 33

What is a cloacal malformation?

Answer 33

Rare, complex malformation in which the GI and GU tracts converge with one another. Poor prognosis, lack of lung development

Question 34

What is a patent urachus/urachal cyst?

Answer 34

ALWAYS MIDLINE- The urachus develops the urinary bladder and closes in the second trimester. US can show a “cystic” area in the bladder dome or anywhere up to the umbilicus. If a diverticulum-like herniation is seen in the dome of the bladder as an adult, this can predispose the patient to adenocarcinoma of the bladder.

Question 35

Prune Belly syndrome, also known as ___ ___ syndrome is what?

Answer 35

Eagle Barrett; Most commonly caused by posterior urethral valves, massively dilated bladder. Postnatally, the decompression of hydronephrosis causes retraction and wrinkling of the skin, giving the appearance of a prune. Associated with pulmonary hypoplasia because of prolonged and severe oligohydraminos. KNOW THIS!

Question 36

The most diagnostic and confirmatory feature for a male is testicles with ____ ____ ____.

Answer 36

bilateral small hydroceles

Question 37

The testicles normally descend between ___ and ___ weeks gestation. The penis can be seen as early as ___ weeks.

Answer 37

26-34; 11-12

Question 38

For a female fetus, the paired ___ ___ and ___ ___ create a hamburger bun appearance. This is easier to see in the __ to __ trimester.

Answer 38

labia majora, labia minora;

second, third