Ch 11 Genitourinary System Flashcards
Urinary tract anomalies are m/c in males or females?
Males (such as horseshoe + polycystic kidneys)
U/s evaluation of kidneys is most optimal at what week?
Week 20 (they appear isoechoic to surrounding tissues)
By what week can the kidneys be identified?
Week 22
(can use CD and/or power doppler to aid in documenting renal arteries)
Kidney length?
20 weeks: 2 cm
Term: 4cm
When is the bladder seen?
As early as 11 weeks, but definitely by 13 weeks
The fetal bladder fills + voids about how many times per hour?
Once
If the bladder is filling, how many kidneys are functioning?
At least 1 - it would not fill if there were none
Fetal urinary production begins at what week?
9 weeks - increases after 16 weeks + makes up 90% of amniotic fluid by 20 weeks
The presence of oligohydramnios after 16 weeks indicates what?
-Suspicious of malfunctioning genitourinary (GU) system due to lack of urine production
-Suspicion of bilateral renal agenesis
Is renal agenesis common?
Unilateral: yes (can live normal lifespan)
Bilateral: no (associated with UPJ obstruction + VUR + incompatible with life)
Where to search for ectopic kidney?
Abdomen, pelvis + renal fossa
(unilateral agenesis will have 1 very large kidney to compensate for missing the other)
Does unilateral agenesis cause a change in amniotic fluid levels?
No, bladder filling remains normal
Where will the adrenal gland be if there is renal agenesis?
In the renal fossa
Differential diagnoses for empty renal fossa?
Renal aplasia, dysplasia, multicystic dysplastic kidney + renal ectopia
What is the m/c location for an ectopic kidney?
Pelvis
SF of an ectopic kidney?
-Smaller, malrotated + irregular shape
-Similar echogenicity to surrounding bowel
-Many are dysplastic or hypoplastic with decreased function
Where is a pelvic kidney located?
Inferior to renal fossa + superior to bladder (either midline or off midline)
What is crossed renal ectopia?
-When a kidney is located on the opposite side from where its ureter inserts into the bladder
-Is fused with the opposite kidney in 90% of cases
What type of cross over is m/c with crossed renal ectopia?
Left to right crossover is m/c
(UP of crossed ectopic kidney m/c fuses to LP of normal kidney)
List 2 u/s findings with crossed renal ectopia?
-Calyceal dilation
-Hydronephrosis
What is the m/c renal fusion anomaly?
Horseshoe kidneys
What is a horseshoe kidney?
-When kidneys fuse at LPs (m/c) creating a U shape
-The ishmus is the connection b/w the 2 renal masses
(best seen in TRV or coronal)
Are horseshoe kidneys m/c lower or higher than normal kidneys?
Lower
What is an obstructive uropathy?
Any blockage of urine flow (m/c in males)
What is one of the m/c fetal anomalies detected on prenatal sonography?
Obstruction
List the measurements for mild, moderate + severe hydronephrosis?
Mild:
-2nd tri: 4-7mm
-3rd tri: 7-9mm
Moderate:
-2nd tri: 7-10mm
-3rd tri: 9-15mm
Severe:
-2nd tri: >10mm
-3rd tri: >15mm
When hydronephrosis is detected in 2nd tri, a follow up u/s must be done at how many weeks?
32 weeks - to determine presence of urinary tract dilation
What is the anterior-posterior renal pelvis diameter that is considered abnormal?
> 5mm
What is the m/c cause of congenital obstructive hydronephrosis?
UPJ obstruction (m/c males + unilateral)
Where does UPJ obstruction occur?
At junction of renal pelvis + ureter
(can be functional (m/c) or anatomic)
SF of UPJ obstruction?
Unilateral hydronephrosis w/o ureter dilation + normal bladder
SF of UVJ obstruction?
Hydronephrosis with dilation of ureter to bladder but w/o dilated bladder
Does unilateral or bilateral UVJ obstruction result in oligohydramnios?
Bilateral
What is a megaureter?
Ureter >7mm from 30 weeks onward
What is VUR (vesicoureteral reflux)?
Permanent or intermittent retrograde flow of urine from bladder into upper urinary tract
(m/c seen during voiding of bladder)
What is a ureterocele?
-Cystic dilation of distal ureter within bladder
-M/c associated with duplicated collecting system + an ectopic ureter insertion
-M/c in females
What is renal duplication?
2 renal collecting systems with or w/o separate ureters (m/c unilateral)
In a duplex kidney, the UP is m/c obstructed due to what?
An ectopic ureter insertion or ureterocele
Urethral atresia is characterized by what 2 things?
-Anhydramnios (absence of fluid)
-Largely distended bladder that fills the entire fetal abdomen + pelvis
(image in slide shows massive bladder taking up whole baby)
What is lower urinary tract obstruction (LUTO)?
-Any condition that blocks urinary flow from the bladder
-Characterized by an enlarged bladder (megacystis) + bilateral hydronephrosis
(high mortality due to oligo + pulm hypoplasia)
What are the 2 m/c causes of LUTO?
PUV (posterior urethral valves - m/c) + urethral atresia
What is the keyhole sign associated with?
Posterior urethral valves
What is a PUV?
An obstructing membrane in the posterior urethra due to redundant membranous folds
(causes bladder to not empty + gets enlarged extending into entire pelvis/abdomen)
SF of PUVs?
-Keyhole sign (point of obstruction)
-Thick walls + dilated bladder
-Dilated prostatic urethra
How many types of PUVs are there?
3 : type 1 is m/c, type 2 is l/c
What is prune belly syndrome?
-Cause of urinary tract dilation
-Is the distention of the anterior abdominal wall
-4x m/c in twin pregnancies
-M/c in males
(image in slide shows massive bladder on baby)
How can prune belly syndrome be resolved?
Place a bladder shunt to drain excess urine + reduce pressure
What is the leading cause of perinatal death?
Pulmonary hypoplasia + is related to oligohydramnios
List the types of polycystic kidney disease (PKD)?
Hereditary:
-ARPKD (recessive)
-ADPKD (dominant)
Nonhereditary:
-MCDK (multicystic dysplastic kidney disease)
-Obstructive cystic dysplasia
-Simple renal cysts
What is ARPKD?
-Bilateral + known as infantile PKD
-M/c cystic disease in pregnancy
-4 types (perinatal, neonatal, juvenile + infantile which is m/c)
SF of ARPKD?
-Multiple small cysts 1-2mm
-Bilaterally enlarged, homogenous + echogenic kidneys with poor corticomedullary differentiation
What is ADPKD?
-M/c inherited kidney disease
-AKA adult PKD (APKD) b/c rare in antenatal life
SF of ADPKD?
-Similar to ARPKD as small cysts are seen
-Can result in enlarged + echogenic kidneys
(can be seen in childhood + utero)
Is ADPKD + ARPKD easy to differentiate?
NO! Must use other form of analysis
What is MDKD?
-Multiple noncommunicating cysts varying in size, separated by dysplastic parenchyma/tissue
-M/c unilateral
-VUR is m/c finding with this
SF of MCDK?
-Multiple large anechoic cysts varying in size
-Increased echogenicity b/w cysts + connective tissue
-Renal pelvis + prox ureter is absent
(image in slide shows kidney full of cysts)
What is commonly seen in the contralateral kidney with MCDK?
Compensatory hypertrophy
What is the m/c cause of nonhereditary fetal renal cystic dysplasia + hyperechoic kidneys?
Obstructive cystic dysplasia
SF of a simple renal cyst?
Single, nonseptated cyst with well defined borders + no communication with renal pelvis
(not common finding)
M/c renal tumor?
Congenital mesoblastic nephroma - only occur in 3rd trimester
(they are large + take up at least half the kidney)
Are kidney tumors common?
No, unusual
What are adrenal glands?
Ovoid, triangular or heart shaped structures m/c in suprarenal region of fetus
What trimester are the adrenals best seen?
3rd trimester (in SAG)
SF of adrenals?
Hyperechoic central medulla with hypoechoic thick outer cortex
(are large in a fetus compared to adults)
Fetal neuroblastomas develop where?
In adrenals
What is the only visualized pelvic organ?
Pelvis
The pelvis consists of what?
Echogenic iliac crests, separated from echogenic sacrum by the hypoechoic sacroiliac joints
What are the 2 m/c abnormalities in the pelvis?
Female reproductive ones:
-internal pelvic masses
-sacrococcygeal teratomas (m/c)
What is the urachus?
Normal embryonic remnant that exists as a fibrous cord that connects the bladder to the allantois
The urachus becomes what ligament?
The median umbilical liagament
(has no function)
What are the 2 m/c types of urachal anomalies?
Urachal sinus + cyst
(fully patent urachus is l/c)
What is the m/c complication associated with urachal anomalies?
Infection
Do cancers have an association with urachal anomalies?
Yes - adenocarcinoma + trasitional cell carcinoma
What is bladder exstrophy?
Severe congenital anomaly that results from failure of mesenchymal cells to migrate b/w ectoderm of abdomen + cloaca, causing eversion of bladder onto abdominal surface
Bladder exstrophy can simulate what other anomalies?
Omphalocele or gastroschisis
What is the cloaca?
Common sinus in embryonic development, which it divides to form the rectum, bladder + genitalia
What is cloacal exstrophy?
Rare congenital disorder due to anomalous development of cloacal membrane
(is most severe anomaly in the spectrum)
At what week is it accurate to identify fetal sex?
After week 20
(from 12-14 weeks the genital tubercle in M/F is indistinguishable)
How to tell the sex of a fetus?
Female: downward angle of tubercle
Male: upward angle of tubercle
What can make it hard to tell if a baby is a male?
-Umbilical cord can look like a penis
-Thighs can hide scrotum
How to tell if the sex is a female?
3 echogenic lines will be seen representing the labia majora + minora
Which trimester is most accurate for evaluating fetal sex?
2nd trimester
What is hypospadias?
Abnormal development of corpus spongiosum + cavernosa urethra due to incomplete fusion of urogenital folds
When does testicular descent occur?
Adbominally: 10-15 weeks
Inguinally: 26-35 weeks
Inguinoscrotal hernias are quite common + most common on which side?
Right
What is the m/c intraabdominal tumor in female fetuses + neonates?
Fetal ovarian cysts
Any ovarian cyst over what size is m/c to experience torsion?
> 5cm
When would ovarian torsion occur?
In large, complex ovarian cysts m/c during or right after the antenatal period
What is disorders of sex development?
A congenital condition where the development of chromosomal, gonadal or anatomical sex is atypical
What is androgen insensitivity syndrome (AIS)?
-Results in a normal female phenotype (46, XY)
-Amenorrhea presents at puberty + testes may be found (bilateral orchiectomy is done)
