2. OUTLINE
• Introduction
• Overview of embryology
• Anomalies of the kidney
-number
-structure
-location
• Anomalies of the urinary tract
-Duplication of ureters
-Ectopic ureters
-Posterior urethral valve
-Bladder anomalies
• Miscellaneous
• -Prune belly syndrome
3. OVERVIEW OR EMBRYOLOGY
• The urinary and reproductive systems develop from the
intermediate mesoderm.
• Urinary system: 3 slightly overlapping systems are formed in a
cranial and caudal sequence during the intrauterine life.
• These are the pronephros, mesonephros, metanephros
4. • PRONEPHROS: develops at the 3rd week of intrauterine life. It is
found in the caudal region. It degenerates leaving behind the
pronephric duct.
• MESONEPHROS: this develops at 4 weeks of gestation. It is found in
the upper thoracic to upper lumbar L3 segments. It degenerates
leaving behind the mesonephric duct
5. METANEPHROS
• The definitive kidney
• Appears in the 5th week of intrauterine life about day 34
• Ureteral bud arises from the mesonephric duct near its junction with the
cloaca
• The ureteral bud grows cephalad collecting mesoderm from the caudal
portion of the nephrogenic cord of the intermediate mesoderm
6. • Ureteral bud gives rise to the renal pelvis, calyces, papillary ducts
and collecting tubules
• The metanephric tissue around dilated tips of ureteral bud, forms
the S-shape hollow vesicles
• S-shaped hollow vesicles gives rise to the Bowman’s capsule. It
elongates to form the PCT, DCT, loop of Henle.
• Small vessels grow into the lower end of the S-shaped nephron
giving rise to the glomerulus
7.
8. POSITION OF THE KIDNEY
• Initially in the pelvic region
• Later ascents to the level of the 1st lumbar or 12th thoracic
vertebrae
• Ascent of the kidney is caused by diminution of the body curvature
and by growth of the body in the lumbar and sacral regions
9. FUNCTION OF THE KIDNEY
• Definitive kidney becomes functional near the 12th week
• Urine is passed into the amniotic cavity and mixes with the
amniotic fluid
• The fluid is swallowed by the fetus and recycles through the
kidneys
• During the fetal life, the kidneys are not responsible for excretion
of waste products
• The placenta serves this function
10. BLADDER, URETHRA, URETERS
• Between the 4th to 7th week, the cloaca divides into the urogenital
sinus anteriorly and anal canal posteriorly.
• This is separated by the urorectal septum
• The tip of the septum forms the perineal body
• The urogenital sinus has 3 parts; bladder (urinary bladder), pelvic
part (prostatic and membranous part of the urethra) phallic part
(genital tubercule)
• The caudal portions of the mesonephric ducts are absorbed into
the wall of the urinary bladder. The ureters enters the bladder
seperately
11. ANOMALIES OF THE KIDNEY
• Anomalies of number
-Bilateral renal agenesis
-Unilateral renal agenesis
- Supernumerary kidneys
• Anomalies of structure
-Renal hypoplasia
-Renal dysplasia
-Renal aplasia
-oligomeganephronia
-Polycystic kidney disease
• Anomalies of location
-Horse shoe kidney
-Ectopic kidney
12. BILATERAL RENAL AGENESIS
• Also known as Potter’s syndrome
• 1:5000 births
• M>F
• Non familial
• Incompatible with extrauterine life
• Death occurs shortly after birth from pulmonary hypoplasia
• Potter’s facies: epicanthic folds, low set ears/malformed ears, broad flattered nose, receding chin.
• Limb anomalies are not uncommon
• Diagnosis is suspected if USS antenatally shows
-Oligohydramnious
-Nonvisualisation of the bladder
-Absent kidneys
-Small for date
13.
14. UNILATERAL RENAL AGENESIS
• 1 per 450-1000 birth
• M>F
• Incidence increased in newborns with single umbilical artery
• Ureter and ipsilateral bladder hemitrigone maybe absent
• Contralateral kidney undergoes hypertrophy
• Maybe asymptomatic
16. ANOMALIES OF THE KIDNEY
• Anomalies of number
-Bilateral renal agenesis
-Unilateral renal agenesis
- Supernumerary kidneys
• Anomalies of structure
-Renal hypoplasia
-Renal dysplasia
-Renal aplasia
-oligomeganephronia
-Polycystic kidney disease
• Anomalies of location
-Horse shoe kidney
-Ectopic kidney
17. RENAL HYPOPLASIA
• Small nondysplastic kidneys
• Has fewer than normal nephrons and calyces
• Can be unilateral – diagnosis is made accidentally
• Bilateral renal hypoplasia manifests with signs and symptoms of
CRF leading to ESRD in the first decade of life.
• There maybe a history of polydipsia and polyuria in these patients
18. RENAL DYSPLASIA
• This is actually a histologic diagnosis
• Refers to focal, diffused or segmentally arranged primitive structure
• Non renal structures such as cartilage maybe present
• Size of the kidney maybe larger or smaller than normal
• Some have associated anomalies such as vesico-ureteric reflux
• Kidney may have cyst leading to multicystic dysplastic kidney (MCDK)
• Maybe asymptomatic if unilateral
• Bilateral disease leads to CRF that may require dialysis and kidney
transplantation.
19. RENAL APLASIA
• Small mass of tissue unrecognized as kidney
• Ipsilateral ureter is usually atretic
20. OLIGOMEGANEPHRONIA
• Small kidneys with reduced number of nephrons
• Nephrons are abnormally large
• Symptoms include: polyuria, vomiting, dehydration, salt wasting
concentration defects, proteinuria.
• The condition later leads to CRF
22. INFANTILE POLYCYSTIC KIDNEY DISEASE
• Inheritance is autosomal recessive
• The affected gene is on chromosome 6 with mutations involving
PKHD1 gene
• F>M; 2:1
• Patients are born with large kidneys and oliguria
• They may be stillbirth or die at birth due to pulmonary hypoplasia
and respiratory failure
• Hypertension in these patients is severe and renal failure usually
occurs
23. INFANTILE POLYCYSTIC KIDNEY DISEASE
• Prenatal USS: enlarged kidneys with increased echogenicity and
loss of normal corticomedullary differentiation
• Histology: small cysts with dilated segments of collecting duct and
distal tubules
• Prognosis is poor even for patients with renal transplantation
24. ADULT POLYCYSTIC KIDNEY DISEASE
• Inheritance is autosomal dominant
• Presents in the 2nd decade of life
• Can present in infancy
• Affected gene is on chromosome 4- PKDI; chromosome 16- PKD2
• CF: abdominal pain, haematuria, hypertension, bilateral abdominal
masses, recurrent febrile episodes.
• Diagnosis by USS and IVU shows enlarged kidneys with widely separated
calyces
• Management: BP control, correction of electrolyte derangement, RRT in
patients with CRF, screen family members with USS.
25. ANOMALIES OF THE KIDNEY
• Anomalies of number
-Bilateral renal agenesis
-Unilateral renal agenesis
- Supernumerary kidneys
• Anomalies of structure
-Renal hypoplasia
-Renal dysplasia
-Renal aplasia
-oligomeganephronia
-Polycystic kidney disease
• Anomalies of location
-Horse shoe kidney
-Ectopic kidney
26. HORSE SHOE KIDNEY
• 1/400-500 birth
• Are seen in 7% of patients with turner syndrome
• Wilm’s tumors are 4x more common in these patients
• Renal function is usually normal
• Usually left alone unless there is complications like infection or stone
formation
27.
28. ECTOPIC KIDNEYS
• The normal process of ascent and rotation of the kidney maybe
incomplete resulting in renal ectopia
• Maybe located in the pelvic, iliac, thoracic, contralateral position
• Incidence is 1/900
• Ectopia maybe bilateral .
29. ANOMALIES OF THE URETERS,URETHRAS AND
BLADDER
• Duplication of the ureters
• Posterior urethral valve
• Bladder abnormalities
30. DUPLICATION OF THE URETERS
• Results from premature branching of the ureteral bud
• Maybe complete or partial
• Maybe unilateral or bilateral
• F>M; 2:1
• There may be stenosis at the uterovesical junction
• CF: dribbling, recurrent infection, reflux, hydroureter, hydronephrosis
• Diagnosis: IVU
• Management: if there is no symptom, then leave it alone. With
symptoms like reflux and recurrent infections, a surgical repair is
necessary
31.
32. POSTERIOR URETHRAL VALVE
• Incidence is 1:8000 boys
• It is the most common cause of obstructive uropathy in children
• About 30% progress to ESRD or CRF later in life
• The urethral valves are tissue leaflets fanning distally from the
prostatic urethra to the external urinary sphincter. A slit-like
opening usually seperats the leaflets
• The prostatic urethra dilates and the bladder muscle undergoes
hypertrophy
• 1/3 have associated vesicoureteral reflux
33. PUV cont
• Prenatal diagnosis (maternal USS)
-Bilateral hydronephrosis
-Distended bladder
-Oligohydramnious
• At birth
-Presence of palpable bladder
-Poor urinary stream
• Later in life
-FTT due to uremia and sepsis
-Recurrent UTI
-Failure to achieve diurnal urinary continence
35. PUV cont
• Diagnosis is established with voiding cystourethrogram (VCUG) which
shows ballooning of the posterior urethra and poor distal filling
• Management
-Neonate: pass a feeding tube for bladder drainage (don’t pass a foleys
catheter)
-Surgery: Transurethral ablation of valve leaflets
-RRT in cases of ESRD
-Supportive treatment such as correction of electrolyte imbalance,
treatment of UTI
36.
37.
38. Prognosis of PUV
• Favorable
-Normal prenatal USS between 18 & 24 weeks gestation
-Serum creatinine <0.8-1.0mg/dl after bladder decompression
-Visualization of corticomedullary junction on renal sonography
• Unfavorable
-Oligohydramnious inutero
-Hydronephrosis before 24 weeks gestation
-Serum creatinine >1.0mg/dl after bladder decompression
-Identification of cortical cyst in both kidneys
-Persistence of diurnal incontinence beyond 5years of age.
39. BLADDER ABNORMALITIES
• These include agenesis, duplication, patent urachus and extrophy
• These conditions are very rare
• In bladder extrophy, the bladder is exposed due to absence of
abdominal wall muscles
• Infections are common in these patients
40.
41. PRUNE-BELLY SYNDROM
• This is also known as Triad syndrome or Eagle-Barret syndrome
• 1:4000 births
• 95% are males
• They have deficient abdominal muscle, undescended testes, urinary tract abnormalities
• Oligohydramnios in fetal life
• Hypoplasia in fetal life
• Many infants are stillborn
• Many patients have vesicoureteral reflux
• Kidneys have various degrees of dysplasia
• Testes are usually intra abdominal
• >50% have abnormalities of musculoskeletal system
• Malrotation of bowel is often present
• Some children with prune-belly syndrome have PUV
42. • Management
-Treat UTI promptly
-Orchidopexy of undesended kidney
-Reconstruction of abdominal wall for cosmetic purposes
-Vesicostomy to relieve obstruction of urethra
• Prognosis
-Depends on the degree of pulmonary hypoplasia and renal dysplasia
-30% develop ESRD later in life
-Renal transplantation offer good result
