Renal

Question 1

Mechanism for the etiology of renal agenesis?

Answer 1

Lack/failur of the ureteric bud to interact with the metaneprhic blastema

Question 2

In bilateral renal agenesis, what are some key findings one sees?

Answer 2

Potter facies, oligohydramnios (from no urine output), pulmonary hypoplasia.

Infants are stillborn or die shortly after birth.

Question 3

What effect does renal agenesis have on the adrenals?

Answer 3

NONE.

Different embryology

Question 4

What test can be done to check on appropriate fetal lung maturity?

Answer 4

Lecithin-sphingomyelin ratio (pulmonary surfactants). Lecithin is main component in mature lungs.

Normal ratio is > 2

Question 5

What is the indication for getting prenatal ultrasound?

Answer 5

First degree relative (parents, siblings, childrent) with congenital solitary kidneys or infants with bilateral renal agenesis

Question 6

What are 3 etiologies of unilateral renal agenesis?

Answer 6

1. Congenital agenesis (embryo-defect; ureteric bud malformation and RET mutations)
2. Involution of dysplastic kidney
3. Multicystic dysplastic kidney.

Question 7

How is the colon positioned vs normal in unilateral renal agenesis? Dysplastic kidney?

Answer 7

In renal agenesis, the colon will be malpositioned into the renal fossa. In dysplastic kidney, colon will be in correct spot

Question 8

Unilateral renal agenesis: more common in males/females? Left or right side?

Answer 8

Males:female ~ 2:1; most commonly on the left side

Question 9

Associated defects in males with unilateral renal agenesis?

Answer 9

Absent ipsilateral epididymis, vas deferens, ampulla, seminal vesicle, and ejaculatory duct (messed up mesonephric duct)

Question 10

Associated defects in females with unilateral renal agenesis?

Answer 10

Unicornuate uterus or uteri didelphis (double chambered uterus with 2 cervices; due to bad promesoneprhos fusion), hematocolpos, infertility

Question 11

What happens to the other kidney in unilateral renal agenesis?

Answer 11

Compensatory renal hypertrophy

Question 12

Those with unilateral renal agenesis are at higher risk of what comorbidities?

Answer 12

HTN, renal insufficiency, proteinuria, VUR

Question 13

Is there indication for VCUG in children with unilateral renal agenesis?

Answer 13

YES. 1/3 will have reflux

Question 14

Etiology of supernumerary kidney?

Answer 14

Two distinct metanephric diverticula form two separate ureteric buds or ureteric bud branches and each meets an independent metanephric blastema

May cause a bifid or duplex ureter

Question 15

What is more common: fused or non-fused crossed renal ectopia?

Answer 15

Fused 90% vs non-fused 10%

• most common is ureteric bud crosses to contralateral blastema, fusing to inferior pole of normal positioned kidney (imagine two kidneys on one side, lower kidney crosses over to other side)

Question 16

Crossed renal ectopia: Males or females? Left or right?

Answer 16

Males > females 2:1; Left > right 2:1

Question 17

Etiology of horseshoe kidney?

Answer 17

Metanephrogenic blastema fuse at lower poles, resulting in the inability to ascend superior to the IMA

Question 18

Horshoe kidney: males or females?

Answer 18

Males > females 2:1

Question 19

Which gene may be mutated in horseshoe kidney?

Answer 19

Sonic hedgehog gene

- involved in renal positioning

Question 20

Associated renal problems and tumors specific to horseshoe kidney?

Answer 20

~1/3 have UPJ obstruction with hydronephrosis (high ureteral insertion)

Highly variable blood supply (multiple renal arteries)

Wilm’s tumor (increased incidence)

Question 21

What two genetic syndromes have increased incidence of horseshoe kidney?

Answer 21

Edward’s syndrome (trisomy 18; 20%)

Turner’s syndrome (45, XO; 60%)

Question 22

During PCNL on a horseshoe kidney, access should be more medial or lateral?

Are calyces more anterior or posteriorly directed?

Answer 22

Medial (closer to vertebrae)

**Calyces are directed posteriorly

Question 23

Associated renal problems with ectopic kidneys?

Answer 23

50% have obstruction with hydronephrosis
25% have VUR
25% have malrotation
–**anteriorly directly renal pelvis vs medial

Question 24

A thoracic ectopic kidney tranverses what foramen into the posterior mediastinum during development?

Is the adrenal gland affected?

Answer 24

Foramen of Bochdalek

Adrenal gland is in normal spot

Question 25

As kidneys ascend during development, they rotate ____ so that the hilum faces the midline/aorta, and outer concavity faces laterally

Answer 25

rotates ventromedially - begins with hilum facing posteriorly

Question 26

Difference b/w Type 1 and Type 2 calyceal diverticulum?

Answer 26

Type 1: upper or lower pole calyx outpouching Type 2: Outpouching with thin connection directly to the renal pelvis

Question 27

If the calyceal diverticulum is located posteriorly, what is the preferred approach for diverticular ablation?

Answer 27

PCNL

Question 28

If the calyceal diverticulum is located at the anterior superior pole, what is the preferred approach for diverticular ablation?

Answer 28

Ureteroscopy

Question 29

If the calyceal diverticulum is located at the anterior mid/lower pole, what is the preferred approach for diverticular ablation?

Answer 29

Laparoscopic ablation

Question 30

Common problems seen with calyceal diverticula? Where in the kidney are they more likely located?

Answer 30

UTIs, nephrolithiasis, milk of calcium (calcium crystals without stones), hematuria. - most commonly are asymptomatic More common in the superior and mid poles

Question 31

What is megacalycosis?

Answer 31

Malformation of renal papillae that results in enlarged and increased number of calyces without evidence of obstruction - male: female 6:1

Question 32

What is the treatment of megacalycosis?

Answer 32

None. No evidence of renal injury in the long term. Important to distinguish it from hydronephrosis to avoid unnecessary procedures.

Question 33

A pt with a solitary kidney has imaging that shows a central tumor between the upper and lower calyces. What is this most likely to be? What imaging test is best used to differentiate?

Answer 33

Hypertrophied column of Bertin, an renal psuedotumor. DMSA scan will show normal or increased radioisotope uptake

Question 34

A solitary, renal parenchyma bulge is seen laterally and on the left kidney that has a normal variant contour. Most likely diagnosis?

Answer 34

Dromedary hump, a renal psuedotumor