Renal Flashcards
Mechanism for the etiology of renal agenesis?
Lack/failur of the ureteric bud to interact with the metaneprhic blastema
In bilateral renal agenesis, what are some key findings one sees?
Potter facies, oligohydramnios (from no urine output), pulmonary hypoplasia.
Infants are stillborn or die shortly after birth.
What effect does renal agenesis have on the adrenals?
NONE.
Different embryology
What test can be done to check on appropriate fetal lung maturity?
Lecithin-sphingomyelin ratio (pulmonary surfactants). Lecithin is main component in mature lungs.
Normal ratio is > 2
What is the indication for getting prenatal ultrasound?
First degree relative (parents, siblings, childrent) with congenital solitary kidneys or infants with bilateral renal agenesis
What are 3 etiologies of unilateral renal agenesis?
- Congenital agenesis (embryo-defect; ureteric bud malformation and RET mutations)
- Involution of dysplastic kidney
- Multicystic dysplastic kidney.
How is the colon positioned vs normal in unilateral renal agenesis? Dysplastic kidney?
In renal agenesis, the colon will be malpositioned into the renal fossa. In dysplastic kidney, colon will be in correct spot
Unilateral renal agenesis: more common in males/females? Left or right side?
Males:female ~ 2:1; most commonly on the left side
Associated defects in males with unilateral renal agenesis?
Absent ipsilateral epididymis, vas deferens, ampulla, seminal vesicle, and ejaculatory duct (messed up mesonephric duct)
Associated defects in females with unilateral renal agenesis?
Unicornuate uterus or uteri didelphis (double chambered uterus with 2 cervices; due to bad promesoneprhos fusion), hematocolpos, infertility
What happens to the other kidney in unilateral renal agenesis?
Compensatory renal hypertrophy
Those with unilateral renal agenesis are at higher risk of what comorbidities?
HTN, renal insufficiency, proteinuria, VUR
Is there indication for VCUG in children with unilateral renal agenesis?
YES. 1/3 will have reflux
Etiology of supernumerary kidney?
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
What is more common: fused or non-fused crossed renal ectopia?
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)
Crossed renal ectopia: Males or females? Left or right?
Males > females 2:1; Left > right 2:1
Etiology of horseshoe kidney?
Metanephrogenic blastema fuse at lower poles, resulting in the inability to ascend superior to the IMA
Horshoe kidney: males or females?
Males > females 2:1
Which gene may be mutated in horseshoe kidney?
Sonic hedgehog gene
- involved in renal positioning
Associated renal problems and tumors specific to horseshoe kidney?
~1/3 have UPJ obstruction with hydronephrosis (high ureteral insertion)
Highly variable blood supply (multiple renal arteries)
Wilm’s tumor (increased incidence)
What two genetic syndromes have increased incidence of horseshoe kidney?
Edward’s syndrome (trisomy 18; 20%)
Turner’s syndrome (45, XO; 60%)
During PCNL on a horseshoe kidney, access should be more medial or lateral?
Are calyces more anterior or posteriorly directed?
Medial (closer to vertebrae)
**Calyces are directed posteriorly
Associated renal problems with ectopic kidneys?
50% have obstruction with hydronephrosis
25% have VUR
25% have malrotation
–**anteriorly directly renal pelvis vs medial
A thoracic ectopic kidney tranverses what foramen into the posterior mediastinum during development?
Is the adrenal gland affected?
Foramen of Bochdalek
Adrenal gland is in normal spot
As kidneys ascend during development, they rotate ____ so that the hilum faces the midline/aorta, and outer concavity faces laterally
rotates ventromedially
- begins with hilum facing posteriorly
Difference b/w Type 1 and Type 2 calyceal diverticulum?
Type 1: upper or lower pole calyx outpouching
Type 2: Outpouching with thin connection directly to the renal pelvis
If the calyceal diverticulum is located posteriorly, what is the preferred approach for diverticular ablation?
PCNL
If the calyceal diverticulum is located at the anterior superior pole, what is the preferred approach for diverticular ablation?
Ureteroscopy
If the calyceal diverticulum is located at the anterior mid/lower pole, what is the preferred approach for diverticular ablation?
Laparoscopic ablation
Common problems seen with calyceal diverticula?
Where in the kidney are they more likely located?
UTIs, nephrolithiasis, milk of calcium (calcium crystals without stones), hematuria.
- most commonly are asymptomatic
More common in the superior and mid poles
What is megacalycosis?
Malformation of renal papillae that results in enlarged and increased number of calyces without evidence of obstruction
- male: female 6:1
What is the treatment of megacalycosis?
None. No evidence of renal injury in the long term. Important to distinguish it from hydronephrosis to avoid unnecessary procedures.
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?
Hypertrophied column of Bertin, an renal psuedotumor.
DMSA scan will show normal or increased radioisotope uptake
A solitary, renal parenchyma bulge is seen laterally and on the left kidney that has a normal variant contour. Most likely diagnosis?
Dromedary hump, a renal psuedotumor
