CONGENITAL ANOMALIES Embryology: The embryological development of the kidney is a long and continuous process which begins in the 3rd week and is completed by about 34-35 weeks of fetal life. Kidney organogenesis is characterised by 3 distinct and linked stages: pronephros, mesonephros and metanephros.
1. CONGENITALANOMALIES Embryology: The embryological
developmentof the kidneyisalongand continuousprocesswhichbegins
inthe 3rd weekandiscompletedbyabout34-35 weeksof fetal life.
Kidneyorganogenesisischaracterisedby3distinctandlinkedstages:
pronephros, mesonephrosand metanephros.
2. 1. Mesonephros: Mesonephros appearsinthe 4thweekof
gestationasa more complex structure immediately afterthe
involutionof the pronephrictubules. Mesonephros containsthe
vesicles -the precursorof mesonephricnephronandthe
mesonephricduct.The proximal endof the mesonephricductformsa
2-layeredcup, Bowmanscapsule. The
glomerulusiscompletedaftercapillariesvascularise thisprimitive
Bowmanscapsule.
3. The mesonephricnephronsare capable of producingurine bythe
9th weeksof gestation and continue todoso until theirinvolution. At
the mesonephricstage,mostcellsinthisorganhave involutedbythe
11th-12th weekas the metanephrosbeginsfunctioning. 2. Metanephros:
The final stage of the kidneyisthe differentationof the metanephros
andarise fromthe uretericbudand the
metanephricblastema(mesenchyme). The renal
pelvis,majorandminorcalycesandterminal collectingductare
formedbythe 10- 13th wksof ges.
Aftermorphogenesiseachkidneycontainsapprox amillionnephrons.
Pathogenesis:abnormal development CAKUT: Congenital Anomaliesof the
Kidneyand Urinary Tract Anomalies of the upperurinarytract:
Anomaliesof number Anomaliesof ascent Anomaliesof formandfusion
Anomaliesof rotation Anomaliesof renal vasculature Anomaliesof the
collectingsystem
4. Anomalies of kidney: 1. Anomaliesof number Renal
aplasia(solitarykidney) Agenesis Bilateral .(
Potterssyndrome-incompatible withlife) Unilateral Supernumerary. 2.
Anomaliesof ascent(position) ectopickidney 3. Anomaliesof
form&fusion Crossedectopiawith&withoutfusion. o
Inferiorectopia. o Sigmoid. o Lump. o L-shaped. o Disc. o
Superiorectopia.
5. Horseshoe kidney: The lowerpole of bothkidneysare
fusedwitheachotherandconnectedbyan isthmus. Both kidneysare
lowerthanthe normal,asthere ascentare blockedbythe inferior
mesenteric artery The longitudinal axisof the kidneysisdirected
downwardandmedially. 4. Anomaliesof size &structure: Hypoplasia
Multicystickidney Polycystickidney: - Infantile - Adult.
Othercysticdisease. Medullarysponge kidney. Medullarycysticdisease
Polycystickidney:
Hereditaryconditioncharacterizedbyprogressivedistortionof the renal
parenchymaby multiple cystsandperitubularfibrosis. Types:
Infantilepolycystickidneys:autosomal recessive,rapiddestructionof
the renal parenchyma of bothsides. Adultpolycystickidneys:
autosomal dominantslowlyprogressive disease causingslow
destructionof the renal parenchymaof bothsides. Cystsof the
liver,spleen,andpancreasmaybe notedinboth types.
7. VUR = mostcommonurologicabnormalityinkids 1% newborns 30 -
45% of childrenwithUTI UTI (upper) =mostcommon seriousbacterial
infectionof childreninthe developed worldin the age of conjugate
pneumococcal andH. fluvaccines(Israel isnotthere yet!! why?)
Management: A. Basedon the rationale that: a. In the absence of
UTI, VUR doesnot cause renal scarring. b.
Uncomplicatedprimaryrefluxhas a natural tendencytoresolve
spontaneously - the likelihoodof resolutionisinverselyproportional
tograde. B. Maintainingurinesterilityisthe cornerstone of"watchful
waiting" medical management. The classicapproach has
beentoofferdailylow-dose prophylacticantibioticsuppressionof
infectionsasthe firstline of treatment. Urine surveillance
Treatmentof underlyingbladderdysfunction Treatmentof constipation
Patient/parentseducation Indicationsforsurgery: 1. Functional
symptomaticbreakthroughUTI. 2. Anatomical VUR urological
abnormalitiese.g.uretericduplication(lesslikelytoresolve
spontaneously). RENAL DUPLICATION Upper pole ureter: - Has
ectopicinsertion - Can endinbladderor outside bladder - Obstructed
Lowerpole - Has normal insertion - Refluxes
8. URETEROCELE A ureterocoeleisacysticdilatationof the
lowerendof the ureter. It may occur witha single system,
orinvolvesthe ureterof one segmentof a duplicated kidney. The
ureterocoele maybe locatedinthe bladder,oritmay openin an
ectopiclocationbelow the bladderneck Treatment: 1.
Endoscopicincisionorureterocele (unroofing) 2. Upper pole
nephrectomy 3. Reinsertionof upperploeureterintolowerpole ureter 4.
Lowerpole ureterreimplantation ECTOPICURETER Sitesof insertion: -
Girls:urethra,vagina,vestibule - Boys:prostaticurethra,genital
tract Urinary incontinence ingirlsif insertionisbelow external
spinchter Infectionorepididymitisinboys Treatment: 1. Upper pole
nephrectomy 2. Reinsertionof upperpoleureterintolower pole ureter
3. Lowerpole ureterimplantation UROGENITAL SINUS
9. Urogenital sinusforms: - Bladder - Pelvicurethra Male Female
Membranous& prostaticurethra Urethra - Definitive
urogenitalsinus Male Female Penile urethra Vagina POSTERIORURETHRAL
VALVES Most commoncause of obstructive uropathyinmales Doesnot
affectfemales Incidence:1/5000-1/8000 Cause:congenital
membranewhich(partially) obstructsurethra Clinical presentation: 1.
bilateral flankmasses(hydronephrosis) 2. distendedbladder 3. poor
urinarystream(+/- dribbling) Diagnostictest:VCUG TherapeuticGoal:
Preserve renal function,avoidrenalfailure (30% at risk
forprogressive renal insufficiency) BLADDER EXSTROPHY
(Exstrophyepispadiascomplex) Spectrumof severity : 1. Small
defectcanresultinepispadias 2. large defectcan resultinexposure of
posteriorbladderwall Occurs in1 in 30,000 births
Exposedbladdermucosaisedematousandfriable HYPOSPADIAS
Incidence:upto1:250 births
Associations:undescendedtesticles(DSD),inguinal hernias
Management:recognition,avoidanceof circumcision Surgery:usuallyby2
yearsof life
10. AMBIGOUS GENITALIA CAH isthe most
commondiagnosisinvirilizedXXinfants Presentation
Hypoglycemia,vomiting,diarrhea,hypovolemia,hyponatremiawith
hyperkalemia, and shock Management Monitorelectrolytes,glucose
17-OHP high(Newbornscreen/LabStudies) Treatment:
glucocorticoids(hydrocortisone) May require
mineralocorticoidsinsalt-wasters EPISPADIAS (openingof external
meatusatthe bladder) Veryrare - more
oftenassociatedwithbladderexstrophy Needearlyreferral forparental
counseling Patientsmaybe totallyincontinent