Fetal Genitourinary Tract Flashcards
Kidneys originate in the embryonic pelvis and migrate ____ during the ____ week of gestation.
superiorly; 13th
The fetal kidney scan be visualized by US as early as ___ weeks as hypoechoic structures ___ to the spine in transverse images.
14 weeks; adjacent
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.)
Mullerian
Is it normal to see fluid in the fetal renal pelvis?
It is a normal finding seen after 24 weeks gestation.
If the renal pelvis is greater than ___ mm AP diameter, a follow up US will be recommended.
7
Fetal ureters, just like Fallopian tubes (will,will not) be seen on US unless they are obstructed.
will not
The fetal urinary bladder is routinely seen by __ weeks.
16
The presence of the bladder is important as it shows ___ function. It should fill and empty every ____ minutes.
renal; 20-30
If you do not see the bladder, ____ in 30 minutes.
rescan
The adrenal glands are _____ in a fetus. They are ___ shaped.
large; comma
The adrenal glands must be differentiated in a fetus so as to not overlook __ __.
renal agenesis.
The determination of ___ ___ is only important in cases of differential diagnosis in cases of GI tract anomalies and chromosomal abnormalities.
fetal gender
What is oligohydraminos?
abnormally decreased amount of amniotic fluid
Many renal anomalies are associated with ___.
oligohydraminos
Why is AFI important to measure?
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.
What is renal agenesis?
The congenital absence of one or both kidneys.
Unilateral renal agenesis is ___, happening in about __ out of 1000 births. It is usually ___ since the other kidney just takes over all function.
common; 1; asymptomatic
There is an association between ___ __ __ and a two-vessel cord. You MUST know this!
unilateral renal agenesis
Bilateral renal agenesis is associated with ___ syndrome.
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!)
Sonographic findings of renal agenesis are:
You will not see kidneys or bladder; oligohydraminos (Make sure that you do not mistake the adrenals for kidneys!)
There are two forms of Potter’s syndrome. Name type 1 and describe.
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.)
There are two forms of Potter’s syndrome. Name type 2 and describe.
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
___ or spontaneously resolving urinary obstructions are rarely associated with any clinical abnormality.
Unilateral
____ obstructions, if undetected and untreated, can lead to renal dysplasia, renal failure, or fetal death.
Bilateral
What is the most common cause of fetal hydronephrosis?
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.
What are some causes of UPJ obstruction? If bilateral and severe this obstruction presents how on US?
fibrous bands, valves or kinks, anomalous vessels;
dilated renal pelvis, thinning of renal cortex, but NOT obstructed ureters
What is a duplicated collecting system?
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.
What is a ureterocele?
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.
What is megaloureter? How would it appear on US?
- a congenitally dilated, unobstructed ureter;
- a tortuous, long, cystic abdominal mass.
- In the fetus, bladder and amniotic fluid would be normal.
What is the most common form of congenital or obstructive megaloureter?
UVJ Urterovesico junction obstruction- UNCOMMON; an obstruction at the level of the distal ureter and the bladder
What is a posterior urethral valve?
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.
What is urethral atresia?
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
What is a cloacal malformation?
Rare, complex malformation in which the GI and GU tracts converge with one another. Poor prognosis, lack of lung development
What is a patent urachus/urachal cyst?
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.
Prune Belly syndrome, also known as ___ ___ syndrome is what?
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!
The most diagnostic and confirmatory feature for a male is testicles with ____ ____ ____.
bilateral small hydroceles
The testicles normally descend between ___ and ___ weeks gestation. The penis can be seen as early as ___ weeks.
26-34; 11-12
For a female fetus, the paired ___ ___ and ___ ___ create a hamburger bun appearance. This is easier to see in the __ to __ trimester.
labia majora, labia minora;
second, third
