5. Paediatrics (GU)

Question 1

Renal agenesis (8)

Answer 1

Can be bilateral (Potter sequence related) or unilateral (reproductive assocations)
Unilateral agenesis:
- US: Absent renal artery or oligohydramnios.
- 70% of women have associated genital anomalies (unicornate uterus or rudamentary horn).
- 20% men missing epididymis and vas deferense on same side, plus seminal vesicle cyst on same (missing) side.
Potter sequence: Insult (maybe ACEi), kidneys don’t form, can’t produce urine, can’t develop lungs (pulmonary hypoplasia)
Pancake adrenal sign: elongated appearance of adrenal not normally molder by adjacent kidney.
Used to differentiate surgically absent vs congenitally absent kidney

Question 2

Horseshoe kidney (5)

Answer 2

Most common fusion anomaly.
Kidney gets hung up on IMA.
Complications from position - easy trauma against vertebral body, should avoid contact sports.
Complications from drainage problems - stones, infection and increased risk of cancer from chronic inflammation (Wilms, TCC and Renal Carcinoid)
Associated with Turners

Question 3

Crossed fused renal ectopia (4)

Answer 3

One kidney comes across midline and fuses with the other.
Each kidney has own orthotropic ureteral orifice to drain through.
“Ectopic kidney is inferior”
Left kidney more commonly crosses to the right.
Complications include stones, infection and hydronephrosis (50%)

Question 4

Prune belly (Eagle Barrett syndrome) (4)

Answer 4

Occurs in males, includes the triad of:
- Poor abdominal musculature
- Hydroureteronephrosis
- Cryptorchidism (bladder distension interferes with descent of testes)

Question 5

Congenital UPJ obstriction (6)

Answer 5

Commonest congenital GU tract anomaly in neonates.
20% bilateral.
Most due to intrinsic defects in circular muscle of renal pelvis.
Rx: Pyeloplasty.
Vessels crossing the UPJ changes management.
Whitaker test - urodynamic study combined with antegrade pyelogram, determines extrarenal pelvis from congenital UPJ obstruction.
Classic Hx: teenager w/flank pain after drinking lots of fluid.
NO associated hydroureter

Question 6

Autosomal Recessive Polycystic Kidney Disease (5)

Answer 6

HTN and renal failure.
Liver involvement differs from adult form (ADPKD). Abnormal bile ducts and fibrosis instead of cysts.
Congenital hepatic fibrosis is always present in ARPKD.
Ratio of liver and kidney disease is inverse.
US: kidneys are smoothly enlarged and diffusely echogenic, loss of corticomedullary differentiation. May not see urine in the bladder in utero.

Question 7

Neonatal renal vein thrombosis (4)

Answer 7

Associated with maternal diabetes.
Usually unilateral (left).
Starts peripherally and progresses towards hilum.
When acute, will cause renal enlargement and chronically will cause atrophy.

Question 8

Neonatal renal artery thrombosis (3)

Answer 8

Occurs due to umbilical artery catheters.
Unlike renal vein thrombosis, does NOT present with renal enlargemet, but with severe HTN.

Question 9

Congenital (primary) megaureter (4)

Answer 9

Term for enlarged ureter which is intrinsic to the ureter (not due to distal obstruction).
Causes include
- Distal adynamic segment (analogous to achalasia or hirschprungs)
- Reflux at the UVJ
- Idiopathic
Distal adynamic type “obstructing primary megaureter” can have some hydro, but usually absence of dilatation of collecting system differentiates this from obstruction.

Question 10

Retrocaval ureter (circumcaval) (3)

Answer 10

Issue with IVC development, grows in a manner that pins the ureter.
Mostly asymptomatic, can cause partial obstruction and recurrent UTI.
IVP will show reverse J or fishhook appearance of ureter.

Question 11

Duplicated system (4)

Answer 11

“Weigert Meyer rule” - upper pole inserts inferior and medially.
Upper pole prone to ureterocele formation and obstruction. Lower pole prone to reflux.
Kidneys with duplicated systems tend to be larger than normal kindeys.
Duplicated system can lead to incontinence in girls (ureter may insert below the sphincter sometimes into the vagina)

Question 12

Ureterocele (3)

Answer 12

Cystic dilatation of the intravesicular ureter, secondary to obstruction at ureteral orifice.
IVP or US will show cobra head sign, with contrast surrounded by a lucent rim, protruding from the contrast filled bladder.
Associated with duplicated system (specifically upper pole)

Question 13

Ectopic ureter (3)

Answer 13

Ureter inserts distal to external sphincter in the vestibule.
More common in females and associated with incontinence in females.
Ureteroceles best demonstrated during early filling phase of VCUG.

Question 14

Posterior urethral valve (5)

Answer 14

Fold in posterior urethra, leading to outflow obstruction and eventual renal failure if not fixed.
Most common cause of urethral obstruction in male infants.
Can be shown on VCUG (abrupt caliber change between the dilated posterior urethra and normal caliber anterior urethra)
Can be shown on fetal MRI: hydronephrosis and “key hole” bladder appearance
“Peri-renal fluid collection is a buzzword, due to forniceal rupture (non specific, can be seen with any obstructive pathology)

Question 15

Vesicoureteric reflux (7)

Answer 15

Normally the ureter enters the bladder at an oblique angle, so a valve is developed. If the angle is abnormal, horizontal reflux can occur.
Can occur in asymtomatic child, but seen in 50% of kids with UTI.
UTI should get VCUG to evaluate for reflux.
Most resolves by age 5-6.
Grading system
- grade 1: Half way up the ureter
- grade 2: reflux into a non dilated collecting system (calyces still pointy)
- grade 3: dilatation of the collecting system and calyces get blunted.
- grade 4: system is mildly tortuous
- grade 5: system is very tortuous
Can get Echogenic mound near the UVJ, due to injection of deflux, the treatment urologists try for this. they make a bubble with this compound near the UVJ in the soft tissues, creating a valve.
Chronic reflux can lead to scarring and on to HTN or chronic renal failure

Question 16

Urachus (6)

Answer 16

Umbilical attachment to the bladder.
Usually atrophies into the umbilical ligament.
Persistent canalization can occur along a spectrum (patent sinus, diverticulum, cyst)
Most common complication of urachal remnant is infection
Urachal anomalies are twice as common in boys relative to girls
When they get cancer, 90% get adenocarcinoma.

Question 17

Renal masses DDx (8)

Answer 17

Neonate
- Nephroblastomatosis
- Mesoblastic nephroma
Age 4
- Wilms
- Wilms variants
- Lymphoma
- Multilocular cystic nephroma
Teen
- RCC
- Lymphoma

Question 18

Nephroblastomatosis (6)

Answer 18

Found in 1% of infants, but can be precursor to Wilms.
When Wilms is bilateral, 99% had nephroblastomatosis first.
Usually self limits. Should NOT have necrosis, if it does, think Wilms
Varied appearance, often described as focal homogenou ball with hypodense rind.
US screening every 3 month until age 7 is routine.

Question 19

Mesoblastic nephroma (5)

Answer 19

“Solid renal tumour of infancy”
Fetal hamartoma, generally benign.
Commonest neonatal renal tumour (80% diagnosed int he first month of life).
Often involves renal sinus.
Antenatal US may have shown polyhydramnios.
If it looks like Wilms, but pt is younger than 1 year, it probably this

Question 20

Multicystic dysplastic kidney (5)

Answer 20

Cystic lesion age 0-3.
Multiple tiny cysts forming in utero,
“no functioning renal tissue”
Contralateral renal tract anomalies occur in 50%, most commonly UPJ obstruction.
In hydroneprosis, the cystic spaces communicate, here they don’t.
In difficult cases, renal scintigraphy can be useful (MCDK will show no excretory function)

Question 21

Wilms (9)

Answer 21

“solid tumour of childhood” - most common one.
NOT seen in newborn.
Average age is around 3.
Spreads via direct invasion.
Associated syndromes
- Overgrowth:
- Beckwith-Weidermann: Macroglossia (most common finding), Omphalocele, Hemihypertrophy, Cardiac, Big organs
- Sotos - Macrocephaly, retardation, facial dysmorphias
- Non-overgrowth:
- WAGR: Wilms, Aniridia, Gental, Growth retardation
- Drash - Wilms, Pseudohemaphroditism, Progressive glomerulonephritis.

Question 22

Wilms variants (looks like Wilms) (2)

Answer 22

Clear cell - likes to go to bones (lytic)
Rhabdoid - “terrible prognosis” - associated with agressive rhabdoid brain tumours.

Question 23

Wilms NEVER… (2)

Answer 23

NEVER biopsy suspected wilms (Can seed the tract and increase stage)
Wilms NEVER occurs before 2 months old, neuroblastoma can

Question 24

Multilocular cystic nephroma (3)

Answer 24

Non-communicating fluid filled locules, surrounded by thick fibrous capsule.
Absence of solid component or necrosis.
“protrudes into renal pelvis”
Occurs in 4 year old boys and 40 year old women.

Question 25

Solid lesions in teenagers (4)

Answer 25

Renal lymphoma and RCC can occur in teens.
Renal lymphoma can occur in 5 year old as well.
Both cancers are discussed in detail in adult GU chapter.

Question 26

Rhabdomyosarcoma (3)

Answer 26

Commonest bladder cancer under 10 years old.
Often infiltrative, hard to tell their origin.
“paratesticular mass” is often buzzword.
Can met to lungs, bones and nodes.
Botyroid variant produces a polypoid mass, looks like bunch of grapes.

Question 27

Neuroblastoms (7)

Answer 27

Not a renal mass, but commonly contrasted with Wilms.
Commonest extracranial solid childhood malignancy.
Occur in very young kids, can be at birth.
95% occur before age 10.
Occur in abdomen more often than thoracic (adrenal 35%, retroperitoneum 30%, posterior mediastinum 20%, neck 5%).
Stage is increased by:
- Crossing midline
- Contralateral positive nodes.
these make stage 3

Question 28

Neuroblastoma associations (3)

Answer 28

Syndromes
- NF-1, Hirschprungs, DiGeorge, Beckwith-Wiedemann.
Most are sporadic

Question 29

Neuroblastoma - trivia (6)

Answer 29

Opsomyoclonus (dancing eyes and dancing feet) - paraneoplastic syndromes associated with neuroblastoma
Raccoon eyes is a common way for orbital neuroblastoma mets to present.
MIBG is superior to conventional bone scan for neuroblastoma bone mets.
Neuroblastoma bone mets are on the “lucent metaphyseal band DDx”
Sclerotic bone mets are uncommon.
Urine catecholamines are in 95% cases elevated.

Question 30

Neuroblastoma vs Wilms (5)

Answer 30

Usually <2YO (can occur in utero) vs Usually around 4, NEVER before 2 months.
Calcifies 90% vs calcifies rarely <10%.
Encases vessels (doesn’t invade) vs Invades vessels
Poorly marginated vs well circumscribed.
Mets to bones vs Doesn’t usually met to bones unless clear cell Wilms variant.

Question 31

Neonatal adrenal haemorrhage (5)

Answer 31

Can occur in setting of birth trauma or stress.
Haemorrhage vs neuroblastoma:
- US can usually tell difference (adrenal haemorrhage is anechoic and hypervascular).
- MRI can be done to problem solve if needed (Adrenal haemorrhage is low T2, neuroblastoma is high T2)
- US should show serial decrease in size.

Question 32

Hydrometrocolpos (6)

Answer 32

Vagina fails to drain the uterus.
Imaging: expanded, fluid filled vaginal cavity with associated distension of the uterus.
Presents in infancy as a mass, or teenager with delayed menarche.
Causes include imperforate hymen (most common), vaginal stenosis, lower vaginal atresia and cervical stenosis.
“midline pelvis mass causing hydronephrosis”
Associated with uterus didelphys, often (75%) has transverse vaginal septum

Question 33

Sacrococcygeal teratoma (5)

Answer 33

Most common tumour of the foetus or infant.
Typically large solid or cystic mass, found on on prenatal imaging or birth.
Can cause mass effect on GI system, hip dislocation and even nerve compression causing incontinence.
Usually benign, but older infants have higher malignant potential.
Mass is either extra pelvic (47%), intrapelvis (9%) or dumbbelled inside and out (34%).
Coccyx is cut off during resection, incomplete resection of the coccyx associated with higher recurrence rate.

Question 34

Sacrococcygeal teratoma classification (4)

Answer 34

Type 1: completely extra pelvic
Type 2: barely pelvic but not abdominal
Type 3: some abdominal
Type 4: Completely intraabdominal (highest rate of malignancy)

Question 35

Ovarian torsion (2)

Answer 35

Usually due to a mass in adult, can be due to excessive mobility of normal ovary in kids.
Enlarged swollen ovary with peripheral follicles, with or without arterial flow.

Question 36

Ovarian masses (4)

Answer 36

2/3 are benign dermoids or teratomas.
1/3 are cancer, usually germ cell.
Mural nodules and thick septations are sus for cancer.
Peritoneal implants, ascites, lymphadenopathy are also sus for cancer.

Question 37

Hydrocele (2)

Answer 37

Collection of serous fluid, most common cause of painless scrotal swelling.
Congenital hydroceles due to patent processus vaginalus, that permits entry of peritoneal fluid into the scrotal sac

Question 38

Complicated hydrocele (with septations) (2)

Answer 38

Either haematocele or pyocele.
Distiction is clinical.

Question 39

Varicocele (5)

Answer 39

Most idiopathic and found in adolescents and young adults.
More frequent on the left.
Uncommon in right and, if isolated, should stir suspicioun for abdominal pathology (Nutcracker syndrome, RCC, retroperitoneal fibrosis).
Needs abdominal CT.

Question 40

HSP

Answer 40

Vasculitis, commonest cause of idiopathic scrotal oedema

Question 41

Acute pain in or near scrotum DDx (3)

Answer 41

Torsion of testicular appendage
Testicular torsion
Epididymo-orchitis

Question 42

Epididymitis (5)

Answer 42

Epididymal head is commonest part involved.
Increased size and hyperaemia on US.
Occurs in 2 peaks, under 2 and over 6.
Can have infection of epididymis alone or with the testicle.
Isolated orchitis is rare unless mumps.

Question 43

Torsion of testicular appendage (4)

Answer 43

Commonest cause of acute scrotal pain ages 7-14.
Testicular appendage is a vestigial remnant of mesonephric duct.
Sudden onset pain with blue dot sign on physical exam.
Enlargement of testicular appendage >5mm is considered best indicator of torsion.

Question 44

Torsion of testicle (4)

Answer 44

Results from testis and spermatic cord twisting within the serosal space, leading to ischaemia.
Caused by a failure of the tunica vaginalis and testis to connect, or “Bell clapper deformity”. This is usually bilateral, so other testis also needs fixed (orchidopexy).
Doppler US shows absent or asymmetrically decreased flow, asymmetric enlargement and slightly decreased echogenicity of involved ball.

Question 45

Paratesticular rhabdomyosarcoma (4)

Answer 45

Commonest extratesticular mass in young men.
Mass in scrotum that isn’t testicule is likely this, unless it’s traumatic haematoma
Most common location for this is actually orbit and nasopharynx.
Bimodal age distribution: 2-4, then 15-17

Question 46

Testicular microlithiasis (4)

Answer 46

Multiple small echogenic foci within the testes.
Usually an incidental finding.
May have relationship with germ cell tumours (contraversial).
Follow up in 6 months, then yearly.

Question 47

Testicular cancer - types (4)

Answer 47

Germ cell (90%)
- Seminoma 40%, seen more in 4th decade.
- Non-seminoma (60%): Teratoma, yolk sac, mixed germ cell
Non germ cell (10%)
- Sertoli
- Leydig

Question 48

Yolk sac tumour (3)

Answer 48

One of 2 seen in first decade of life (other is teratoma).
Heterogenous testicular mass in <2 year old is yolk sac tumour.
AFP is very elevated.

Question 49

Teratoma (3)

Answer 49

Pure testicular teratomas are only seen in young kids <2.
Mixed teratomas are seen in 25 year olds.
Unlike ovarian teratoma, these are aggressive

Question 50

Choriocarcinoma

Answer 50

Agressive, highly vascular tumour seen usually in 2nd decade.

Question 51

Sertoli cell tumours (3)

Answer 51

Usually bilateral, seen on US as “burned out” tumours (dense echogenic foci representing calcified scars).
Subtype of sertoli cell tumour associated with Peutz-Jeghers syndrome typically occurs in kids.
Peutz-jehger lips and bilateral scrotal masses is probably this

Question 52

Testicular lymphoma (4)

Answer 52

Can “hide” in testes due to blood testes barrier.
Immunosuppressed patients are at increased risk for developing extranodal/testicular lymphoma.
US: normal homogenous echogenic testicular tissue is replaced focally or diffusely with hypoechoic vascular lymphomatous tissue.
“Multiple Hypoechoic Masses of the Testicle”