RENAL MALFORMATIONS Flashcards
RENAL MALFORMATIONS
Embryology
3 phases of development 1.Pronehros ✓ D22 ✓ Nephrotoms and pronephric duct
2.Mesonephros
✓ Mesonephric duct cloaca
3.Metanephros
Renal agenesis
✓ The kidney does not develop ↑ • Abnormal formation of the mesonephric duct • No ureteric bud • Abnormal metanephric blastema formation
Renal dysgenesia
✓ Abnormal kidney development (size, structure)
✓ Pathological entities:
- Hypoplasia – small number of nephrons
- Dysplasia - primitive duct persistency
- Cystic dysplasia – multicystic dysplasic kidney (cystic kidney disease)
Cystic kidney disease
❑ Genetic
✓ Polycystic renal disease (autosomal dominant/ recessive)
✓ Congenital nephrosis
✓ Different syndroms (ex. Von Hippel Lindau, tuberous sclerosis)
❑ Non-genetic
✓ Multicystic kydney
✓ Acquired cystic kidney disease
✓ Pyelogenic cyst/ Caliceal diverticulae
Kidney position anomalies
❑ Renal ectopy
▪ Lower position of the kidney
Normally: pelvis lombar area
❑ Horseshoe kidney
❑ Sigmoid kidney
+/- simptoms (litiasis, UTI, VUR, HN)
MALFORMATIONS OF THE URINARY TRACT
PRENATAL DIAGNOSIS
n = 3800/10 years Ureteropelvic junction (UPJ) obstruction - 50% Vesico-ureteral reflux - 15% Multicystic kidney - 10% Duplications /Ureterocele - 10% Megaureter - 9% Posterior urethral valve (PUV) - 4% Other malformations - 2%
UPJ (ureteropelvic junction) obstruction and congenital HN
✓ intrinsic +/- extrinsic (abnormal blood vessels, adhesions) UPJ obstruction
↓
✓ Reduction of the urinary flow
✓ Pelvic and caliceal dilatation
✓ Less renal functional parenchyma ➔ RI (potential renal insufficiency)
ANTENATAL DIAGNOSIS
ULTRASOUND
Weeks: 12, 20, 32-34
- evaluate the volume of the amniotic fluid
- kidney position, renal parenchyma evaluation
- +/- type of dilatation/ degree
Malformations of the UT
ANTENATAL DIAGNOSIS
- FETAL MRI
- BIOCHEMISTRY
- fetal urinanalysis
- amniotic fluid- for associated anomalies
- fetal blood tests (if needed)
ANTENATAL DIAGNOSIS - Hydronephrosis
The Society for Fetal Urology
Diagnosis criteria
Grade,Central Renalcomplex,RenalParenchymalThickness
0 Intact Normal
1 Urine in pelvis barely splits sinus, Normal
2 Evident splitting of pelvis & major calyces,Normal
3 Wide splitting of pelvis,major&minor calyces,Normal
4 Further splitting of pelvis,major & minor calyces,Reduced
Malformations of the UT
PRENATAL ULTRASOUND
IDENTIFYING
AT-RISK PATIENTS
! Correlate with post-partum evaluation
First trimester ultrasound @ 20 weeks < 5 mm pelvic AP diameter - normal > 5 mm pelvic AP diameter - abnormal ? Ureteral dilatation ? Any abnormalities of the bladder
• Second trimester ultrasound @ 32-34 weeks
< 10 mm pelvic AP diameter - normal
> 10 mm pelvic AP diameter - abnormal
Malformations of the UT
Pathophysiological mechanism
Renal obstruction ↓ Oligohydramnios ↓ Pulmonary hypoplasia
Malformations of the UT
Disease history
+/- antenatal diagnosis of a pelvic dilatation
? Any UTI episodes so fac
specific data regarding birth and perinatal period
Malformations of the UT
Clinical examination
can be normal
evaluate hydration status, examine external genital organ, identify potential malformations
abdominal examination- any lombar mass?
UTI: lower (cystitis) or renal (pielonephritis) +/- febrile
intermitent lumbar pains
Malformations of UT
Lab investigations
TBC
clotting tests
urea, creatinine
urinanalysis, culture
First postnatal ultrasound - when to do it?
Normally after 48 ore
BUT earlier if:
✓ bilateral anomalies identified antepartum
✓ only one kidney
✓ oligohydramnios
✓ unilateral severe anomalies identified antepartum
Ultrasound and creatinine level normal => next ultrasound at 1 month of age
Important criteria: particularities of the patient, medical team experience
Ultrasound before any surgery
Postnatal ultrasound - what do we evaluate ?
AP pelvic diameter potential caliceal dilatations renal parenchyma index potential ureteral dilatations potential bladder anomalies- examination pre- and post evacuation
Prognostic factors - morphology
✓Renal parenchyma - index - ecogenicity ✓ Caliceal dilatations - central - peripheric ✓ AP pelvic diameter ✓ Extrarenal pelvic surface ✓ Correlation of pre/postnatal examinations!!!
Postnatal ultrasound
< 15 mm Normal
15-20 mm Moderate dilatation
> 20 mm Severe dilatation
The risk of needing a surgical interventions
correlation with the AP diameter of the pelvis
< 20 mm 11 % 20-30 mm 40 % 30-40 mm 90 % 40-50 mm 100 % > 50 mm 100 %
Caliceal aspect
0-5 mm Normal
6-10 mm Moderate dilatation
> 10 mm Severe dilatation
Hydronephrosis index
Defined in 2008 (Shapiro)
◦ HI = % 100 x (Total area of the kidney - area
of dilated pelvis and calices)/(Total area)
◦ Quantified method to provide a reproducible
measure of HN that can be used for all conditions
◦ Higher sensitivity for third and fourth degree anomalies
◦ Great tool for monitoring evolution
◦ Standardized and reprocible
Prognostic factors - function
Renal scintigraphy
Useful for evaluating glomerular filtration and renal excretion
BUT it can also identify morphological anomalies unidentified by the ultrasound
➢ Normal values for the newborn 45-55%
➢ Normally variations< 4% between subsequent evaluations
OPTIONS: Dynamic scintigraphy DMSA; DTPA; MAG3 + furosemide
Renal scintigraphy
✓Glomerular filtration (Technetium 99m- DTPA)
✓Tubular excretion (Technetium 99m- MAG3)
✓General principle – the radionuclide molecule will attach to the renal proteins (i.e.
Technetium 99m- DMSA)
✓ Results :
< 15% Severe renal dysfunction
15-40% Moderate renal dysfunction
> 40% Normal renal function
1.Significant morphological
abnormalities →
2.Major morphological abnormalities →
- Zero function
2. Pseudonormal function…
The role of urography + MRI
Anatomical and functional evaluation
100% sensitivity and specificity for the diagnosis of polar vessel obstruction
Therapeutic options
PRENATALLY -How we decide what needs to be done?
Second trimester ultrasound @ 32-34 weeks
< 10 mm pelvic AP diameter
No caliceal dilatation
Normal echogenicity of the parenchyma
No associated abnormalities of the lower urinary
tract
NO antibiotic prophylaxia, micturating cystourethrogram (MCUG) or scintigraphy
YES ultrasound at 3 months ans 12 months of age
Second trimester ultrasound @ 32-34 weeks > 10 mm pelvic AP diameter ? PUJ obstruction - Caliceal dilatations - Normal ureters - Normal urinary bladder Ultrasound+ MAG3 Renal scintigraphy 4-6 weeks post-partum
- Bilateral HN
- Ureteral dilatation
- Abnormal bladder
(>3mm bladder wall, abnormal evacuation)
Antibiotic prohylaxia
Additional investigations
slide 40,41,42,50
PUJ Obstruction - spotaneous evolution
35 % SURGERY
35 % SPONTANEOUS
FAVOURABLE EVOLUTION (1 - 3 years)
30 % SAME ASPECT IN TIME
Indications for surgical treatment
Renal function < 40% or a decrese in function of
more than 10% from one examination to another
Pelvic AP Ø > 30 mm
Pieloplasty - surgical approaches
✓ Laparotomy
✓ Laparoscopy
✓RALP- Robotic Assisted Laparoscopic Pyeloplasty
Open surgery
Laparoscopic surgery
Hynes Anderson procedure
HN abnormal blood vessel - Vascular Hitch
- Ureter above the constricted area
- Abnormal blood vessel
- Ureter below the constricted area
Fetal surgery
Prenatal retrieval of obstruction +/-?
Subvesical obstacles Oligohydroamnios Normal cariotype Complication rate 45% Still ongoing debate regarding the benefits of such intervention on the renal function!
Potential post-operative complications
Problems with the sutures
Urinoma formation
Later stenosis
IMMEDIATE POSTOP MONITORING
temperature diuresis +/- drainage (if one inserted in the lumbar area at the end of the procedure) presence of bowel movements
Criteria for discharge
normal temperature
normal diuresis
good aspect on the ultrasound (smaller dilatation)
bowel movements present
no drainage
good healing of wounds
ANTIBIOTIC PROPHYLAXIS if internal urinary drainage
Later monitoring
at 4-6 weeks after the surgery - urinalysis, culture - ultrasound - removal of internal urinary drainage Further evaluations at 3, 6, 12 months after the surgery
