1. Introduction to Pediatric Nephrology
Introduction to Pediatric Nephrology
Dr.Fahad Gadi, MD
Pediatrics Demonstrator
King Abdulaziz University
Rabigh Medical School

2.
Kidney ontogenesis
The embryological development of the kidney is a long and continuous process which begins in the 3rd week and is completed by about weeks of fetal life.
Kidney organogenesis is characterised by 3 distinct and linked stages: pronephros, mesonephros and metanephros.

3.
Kidney ontogenesis
In humans, the first two are transient structures with little excretory capacity but they are important for the appropriate development of the metanephros, which is the direct precursor of the adult kidney.

4. After morphogenesis each kidney contains approx a million nephrons.
METANEPHROS
The final stage of the kidney is the differentation of the metanephros and arise from the ureteric bud and the metanephric blastema (mesenchyme).
The renal pelvis, major and minor calyces and terminal collecting duct are formed by the 10-13th wks of ges.
After morphogenesis each kidney contains approx a million nephrons.

5. Renal development Pronephros Przednercze Mesonephros Śródnercze
Renal development
aorta
nefrotomy
Pronephros
Przednercze
3 t.ż.
4-8 t.ż.
przewód Wolffa
Mesonephros
Śródnercze
5 t.ż.
stek
pączek moczowodowy
Metanephros
Nerka ostateczna
blastema nerki ostatecznej

6. Antenatal Period The most common cause is physiologic dilation.
Metanephric urine production begins at 8 weeks, even before ureteral canalization is complete.
Transient obstruction with hydronephrosis occurs.

7. Embryology

10.
MOLECULAR ASPECT
The development of the metanephric kidney depends on inductive interaction between the ureteric bud (UB) and the metanephric mesenchyme (MM).
A large number of genes have been found to be crucial during kidney development.

11.
Nephrons
In the fetus at 36 weeks’ gestation there is an adult complement of nephrons- approx. one million
All further growth of the kidney is via hyperplasia mainly in the tubules.

12.
Fetal kidney
Nephrogenesis is completed between the 28 and 36th gestational week in the human, the renal tissue and particularly the tubular cells continue to develop postnatally.
Several of the major transporters in the tubular epithelial cells undergo postnatal maturation

13.
Fetal kidney
Outer cortical glomeruli are relatively underperfused compared with inner cortical glomeruli.
Following birth, renal perfusion to superficial cortical nephrons rises compared with deeper glomeruli

14.
Fetal kidney
Angiotensin-converting enzyme inhibitors and angiotensin-receptor antagonists impair nephrogenesis and so are contraindicated in pregnancy

15. Production of urine starts at the age of 10-12 weeks of gestation:
Production of urine starts at the age of weeks of gestation:
1. very dilute urine
2. small amount of urine
Fetal urine is a major constituent of amniotic fluid and urinary flow rate increases from 12ml/hr at 32 weeks’gestation to 28ml/hr at 40 weeks’gestation.
Similar increases are described during the maturation of premature newborns.

16. Glomerular Filtration Rate (GFR)
Glomerular Filtration Rate (GFR)
Glomerular filtration begins between the 9th and 12th week of gestation in humans.
The GFR is relatively low at birth especially in the premature infant.
The values of GFR nearly double between 3 and 7 days and thereafter GFR continues to increase, by 1 to 2 yrs of age the GFR is the same as in an older child- 80% of mature kidney.

17.
GFR

18.
Kidney of newborn
The kidney of the newborn infant has a limited capacity to regulate the excretion of fluid and electolytes.
The high sodium excretion during the first 2 to 3 weeks often results in a negative sodium balance and predisposes to hyponatremia.

19. Creatinine Clearance Newborn: 40-65 ml/min/1.73 m2
Creatinine Clearance
Newborn: ml/min/1.73 m2
<40 yrs: ml/min/1.73 m2

20. Renal failure in the newborn
Renal failure in the newborn
Renal failure in the newborn:
severe asphyxia,
the majority suffered from nonoliguric renal failure

21.
CAKUT
Congenital
Anomalies of
Kidney and
Urogenital
Tract

22. CAKUT Chronic renal failure (children): Obstructive nephropathy- 47%
CAKUT
Chronic renal failure (children):
Obstructive nephropathy- 47%
Reflux nephropathy- 18,5%
Hypo/dysplasia 8,7%

23. bilateral fetal death- Potter syndrome 1:4000 pregnancies
RENAL ABNORMALITIES
Renal agenesis:
bilateral fetal death- Potter syndrome 1:4000 pregnancies
unilateral other organ- 1:2900 pregnancies abnormalites

25.
Renal abnormalities
Agenesis Aplasia Hypoplasia

26.
RENAL ABNORMALITIES
Hydronephrosis

27. Obstractive uropathy:
RENAL ABNORMALITIES
Obstractive uropathy:
A. ureteropelvic junction obstruction- dilated renal pelvis with/ without caliectasis and no dilation of the ureter
B. ureterovesical junction obstruction (megaureter)- pelviectasis and caliectasis with significant ureter dilation

28. C. posterior urethral valve
RENAL ABNORMALITIES
C. posterior urethral valve
D. ureterocele- cystic dilatation of the distal ureter that protrudes into the urinary bladder, may extend past the bladder into urethra
E. ectopic ureters
F. constriction (stenosis)of urethra

29. Posterior urethral valve
Posterior urethral valve
Type I – Type II Type III

30. Duplication of urinary tract
Duplication of urinary tract
Ureter Ureter Ureter
duplex fissus

31. • Mothers with VUR in the past 60%
Vesico-ureteral reflux
Frequency of VUR
• Isolated % (0.4-4%)
• UTI in the past %
• Siblings with VUR %
• Mothers with VUR in the past 60%

32. autosomal dominant p.k.disease autosomal recessive p.k. disease
RENAL ABNORMALITIES
Polycystic kidney:
autosomal dominant p.k.disease
autosomal recessive p.k. disease

33.
Kidney ontogenesis

34.
PRONEPHROS
Pronephros is a transitory non-functional kidney, the first tubules appear the middle of the 3rd week and arise from intermediate mesodermal cells.
The pronephric tubules persist for only a short time and undergo degeneration by the 5th week.
At the time the pronephros is degenerating the mesonephric tubules and duct are developing.

35.
Pronephros

37. Vesico- ureteral reflux
                                         
                                           
Vesico- ureteral reflux
Normal kidney, ureter, and bladder

38. Vesico- ureteral reflux
Vesico- ureteral reflux
Grade I Vesicoureteral Reflux: urine (shown in blue) refluxes part-way up the ureter

39. Vesico- ureteral reflux
Vesico- ureteral reflux
Grade II Vesicoureteral Reflux: urine refluxes all the way up the ureter

40. Vesico- ureteral reflux
Vesico- ureteral reflux
Grade III Vesicoureteral Reflux: urine refluxes all the way up the ureter with dilatation of the ureter and calyces (part of the kidney where urine collects)

41. Vesico- ureteral reflux
Vesico- ureteral reflux
Grade IV Vesicoureteral Reflux: urine refluxes all the way up the ureter with marked dilatation of the ureter and calyces

42. Vesico- ureteral reflux
Vesico- ureteral reflux
Grade V Vesicoureteral Reflux: massive reflux of urine up the ureter with marked tortuosity and dilatation of the ureter and calyces

43. International Classification of VUR
International Classification of VUR
Io IIo IIIo IVo Vo