Congenital anomalies of kidney.

CONGENITAL ANOMALIES OF
KIDNEY
Dept of Urology
Govt Royapettah Hospital and Kilpauk Medical College
Chennai
1

Moderators:
Professors:
• Prof. Dr. G. Sivasankar, M.S., M.Ch.,
• Prof. Dr. A. Senthilvel, M.S., M.Ch.,
Asst Professors:
• Dr. J. Sivabalan, M.S., M.Ch.,
• Dr. R. Bhargavi, M.S., M.Ch.,
• Dr. S. Raju, M.S., M.Ch.,
• Dr. K. Muthurathinam, M.S., M.Ch.,
• Dr. D. Tamilselvan, M.S., M.Ch.,
• Dr. K. Senthilkumar, M.S., M.Ch.
Dept of Urology, GRH and KMC, Chennai. 2

CONGENITAL ANOMALIES OF KIDNEY
• ANOMALIES OF RENAL NUMBER
• ANOMALIES OF RENAL ASCENT
• ANOMALIES OF RENAL FORM AND FUSION
• ANOMALIES OF RENAL ROTATION
• ANOMALIES OF THE RENAL COLLECTING
SYSTEM
3
Dept of Urology, GRH and KMC, Chennai.

ANOMALIES OF RENAL NUMBER
• Bilateral Renal Agenesis
• Unilateral Renal Agenesis
• Supernumerary Kidney
4

Bilateral Renal Agenesis
• Agenesis- congenital absence of an organ
resulting from failure to develop during
embryonic growth and development because
of the absence of primordial tissue
• B/L: Incompatible with life
5

INCIDENCE
• Only about 500 cases reported in the
literature
• 75% of affected individuals are males
• Increasing maternal age- risk factor
• USG screening has been recommended for
parents and siblings of infants born with BRA-
URA(4.5%)
6

Syndromic associations with BRA have been
detected in higher than expected proportions in
cases with
• Esophageal atresia,
• Cryptophthalmos
• Fraser syndrome (syndactyly, renal abnormalities,
genital malformations, and cryptophthalmos)
• Klinefelter syndrome
• Kallmann syndrome
7

EMBRYOLOGIC BASIS
• result of a failure of the UB to develop from
the MD/WD or
• failure of the reciprocal induction of the UB
and the metanephric blastema
8

Mutations
• GDNF, RET, Wnt11(UB)
• Gremlin 1 (MM)
• RAS
9

Gross findings in retroperitoneum
• Complete absence of the renal vessels- 25%
• Complete ureteral atresia was observed in 39
of the 42 cases
• Hyposplastic/ absent bladder- UB stimulation,
lack of urine
• Insult before 5th week- gonads absent
10

• adrenal gland may
appear flattened,
elongated (“lying
down” sign)
• orthotopic
• Cortex-primitive
mesoderm, medial to
the urogenital ridge.
• The medulla -
ectodermal neural
crest cells
• Fused and/or
horseshoe-shaped
adrenal glands have
been noted on prenatal
ultrasound screening
11

Phenotypic features- Dr. Edith Potter
• Potter facial appearance- prominent fold and skin crease beneath each
eye, blunted nose, and depression between the lower lip and chin.
• The ears give an impression of being low set because lobes are broad and
drawn forward, but actually the ear canals are located normally.
12

• The skin can be excessively dry and appears
too loose for the body.
• The hands are relatively large and clawlike.
• The legs are often bowed and clubbed
• A lumbar meningocele with or without the
Arnold-Chiari malformation and
hydrocephalus
• Anamolies of the GIT- 60%
13

• Genital abnormalities in a male fetus with BRA
– absence of the scrotum.
– The testes are undescended in 43% of cases
– testicular agenesis in 10% of cases
• Genital abnormalities in a female fetus with BRA
– Clitoral hypertrophy
– The ovaries are frequently hypoplastic or absent.
– The uterus is usually rudimentary or bicornuate but
occasionally absent.
– The vagina is a short, blind-ending pouch or is
completely absent.
14

Role of Amniotic Fluid Production in Fetal
Pulmonary Development
• canalicular phase- 16 and 26 weeks’ gestation,
dependent on the presence of amniotic fluid
• Fetal kidney- proline, which is a prerequisite for
collagen formation in the bronchiolar tree.
• two-step process in pulmonary development
– primary “renal growth factor” influencing early lung
development
– amniotic fluid volume–dependent phase influencing
later gestational lung growth
15

Prenatal and Postnatal Diagnosis of Bilateral Renal
Agenesis
• Prenatal USG:
– second or third trimester
– severe oligohydramnios is noted
– no renal parenchyma can be identified
– Additional diagnostic findings
• small lung volumes and chest diameter
• abnormal adrenal gland appearance
• After the first 24 hours, anuria without any distention
of the bladder is strongly suggestive of BRA.
16

Postnatal Radiographic Evaluation of a Neonate
With Bilateral Renal Agenesis
• Power Doppler ultrasonography
– determining the status of the renal arteries and
documenting blood flow, even in fetuses with
suspected BRA
• Radionuclide scan with 99mTc-DMSA
– If USG is inconclusive
– can be performed at any time after birth.
– The absence of uptake of the radionuclide in both
renal fossae above background activity and in an
ectopic location confirms the diagnosis of BRA.
17

Prognosis
• About 40% -stillborn.
• If born alive, most do not survive beyond the
first 24 to 48 hours because of respiratory
distress
• Experimental: weekly serial amnioinfusion-
improving fetal pulmonary development. After
delivary- daily peritoneal dialysis. 9 month
survivor
18

UNILATERAL RENAL AGENESIS
• Condition in which an individual is born with a
nonectopic, solitary functioning kidney (SFK) and
failure of the contralateral kidney to develop.
• Most often an isolated event that occurs sporadically
• Few instances it is actually secondary to an identifiable
chromosomal abnormality or as part of a constellation
of developmental defects, such as
– VATER (vertebral, anorectal, tracheoesophageal, renal) or
– MURCS (Müllerian duct aplasia, uterine hypoplasia, renal
aplasia, cervicothoracic somite dysplasia)
19

Incidence
• 1 of 1100 births
• Male-to female ratio of 1.8 : 1
• More frequently on the left side
• Autosomal dominant inheritance with a 50%
to 90% penetrance
20

Genetic/Syndromic and Other Associations
• Syndromes associated
– Turner syndrome
– Poland syndrome
– Fraser syndrome
– branchio-oto-renal (BOR) syndrome
– DiGeorge anomaly
• 30% of children with the VACTERL association have URA
• Children with supernumerary nipples and disorders of the
ears with hearing loss, especially if it is congenital and
preauricular pits- increased incidence of URA
• Maternal diabetes is associated with a threefold increased
risk for renal agenesis and dysplasia
21

Embryology
• Complete absence/aborted UB
– prevents reciprocal induction of the metanephric
blastema.
• The metanephros
– not likely to be responsible for the majority of cases,
– because the ipsilateral gonad (derived from adjacent
mesenchymal tissue) is rarely absent, malpositioned,
or nonfunctioning
22

• Embryologic insult affects the UB primarily in its
early development and influences the
development of WD derivatives.
• 4 or 5 weeks’ gestation, when the UB forms and
the WD begins to develop into the ejaculatory
duct, seminal vesicle, and vas deferens
• The MD in the female begins its medial migration
at this time, crossing over the WD (sixth week)
during its differentiation into the fallopian tube,
uterine horn and body, and proximal vagina
23

• Magee et al. proposed an embryologic
classification to explain the association of URA
and MD anomalies
– type I URA
– type II URA
– type III URA
24

In type I URA
• the insult occurs
before the fourth
week of gestation
• there is
nondifferentiation of the
urogenital ridge
structures, including the
MD and WD.
• If unilateral, a uterus
consisting of a single MD
(unicornuate uterus) will
form and will be
associated with
contralateral renal
agenesis.
25

In type II URA,
• the insult occurs early in
the fourth week of
gestation
• affect both the WD and the
UB.
• Because it is critical that the
MD maintains close contact
with the WD for MD
elongation and subsequent
fusion, maldevelopmentof
the WD affects renal
development, MD elongation,
contact with the urogenital
sinus, and subsequent fusion.
• Therefore, a didelphys uterus
will form with obstruction of
the horn and vagina on the
side of the URA.
26

In type III URA,
• the insult
occurs after the
fourth week of
gestation, and the
WD and MD
elongation and
differentiation
proceed normally.
• In this case, only
the UB and
metanephric
blastema are
affected, thereby
resulting in
isolated URA. 27

Associated urinary anamolies
• VUR-most commonly associated urologic
comorbidity
• The ipsilateral ureter is absent in about 60% of
cases with URA
• Contralateral ureter
– Ureteropelvic- 11%
– ureterovesical junction obstruction- 7%
– reflux in 30%
28

• Endoscopic appearance of the trigone in this
setting has led to the probable misnomer in the
case of the
– “hemitrigone” (in association with complete ureteral
agenesis) or
– “asymmetrical trigone” (in the presence of a partially
developed ureter)
• The trigone may not be distinguishable from the
surrounding detrusor when the intramural ureter
is absent
29

Anamolies in male
• Mesonephric tubule derivatives:
– The testis and head of the epididymis are
invariably present
• WD derivatives:
– the body and tail of the epididymis, vas deferens,
seminal vesicle, ampulla, and ejaculatory duct
– absent in almost 50% of cases with URA
30

Anomalies in the Female
• Magee- embryologic classification
• OHVIRA- syndrome of Obstructed HemiVagina
and Ipsilateral Renal Anomaly
• Herlyn-Werner-Wunderlich syndrome
– Obstruction of one side of a duplicated system-
unilateral hematocolpos or hydrocolpos
associated with a pelvic mass and/or pain has
been described in pubertal girls
31

Rokitansky-Küster-Hauser syndrome (MRKH)
• Type I
– typical form characterized by the finding of only
symmetrical muscular buds or Müllerian remnants and
normal fallopian tubes.
• Type II
– which is more common but considered the atypical form
– characterized by asymmetrical hypoplasia of one or two
buds with or without dysplasia of the fallopian tubes.
– associated with renal anomalies, primarily URA, ectopia of
one or both kidneys, or horseshoe kidney in about 40% to
60%
32

MURCS association
• Müllerian duct aplasia (96%)
• renal aplasia or ectopia (86%)
• cardiothoracic somite dysplasia (two to four
anomalous vertebrae between C5 and T1
[80%]
33

Diagnosis and Radiographic Evaluation
• About 90% of fetal kidneys associated with a
contralateral URA or MCDK undergo
compensatory hypertrophy in utero from 20
weeks’ gestation
• USG with Doppler, DMSA
• VCUG may be performed because there is a
28% incidence of contralateral reflux
34

Special consideration
• Data from the National Athletic Trainers’
Association High School Injury Surveillance
Study, which calculated the rates for sport-
specific injuries to select organs
• Summary- having a solitary kidney does not
preclude an individual from safely
participating in sports and athletic activities.
35

Current recommendation- children with SFK
• Annual assessments of blood pressure and
microalbuminuria (first morning specimen)
when there is no CAKUT
• biannually when there is CAKUT, because
hypertension and microalbuminuria
(>30 mg/24 h) are hallmarks of progressive
decrease in glomerular filtration rate
36

SUPERNUMERARY KIDNEY
• More than two kidneys detected within an
individual
• the additional kidney(s) are called supernumerary
kidneys.
• The supernumerary kidney is truly an accessory
organ with its own
– collecting system
– blood supply
– distinct encapsulated parenchymal mass.
• Three or more separate kidneys can form with
the additional renal units usually being smaller
37

• The two main kidneys are commonly
– functionally normal
– equal in size
– orthotopicallylocated.
• The supernumerary kidney may be either
– totally separate from the normal kidney on the same side or
– connected to it by loose areolar tissue .
• The ipsilateral ureters may be
– bifid or
– completelyduplicated.
• The condition is not analogous to a single kidney with ureteral
duplication in which the collecting systems drain portions of one
parenchymatous mass surrounded by a single capsule
38

Incidence
• Only about 100 cases have been reported
• Males and females equally
• Higher predilection for the left side
• Four cases of bilateral supernumerary kidneys
have been reported
39

Supernumerary kidney
which separate entirely
Divide into two metanephrictails
Penetrateand induce the metanephros
Bifid or separate uretericbud
A second UB/branchingfrom the initial UB
40

• WD, UB, GDNF, SLIT2/ROBO2
41

DESCRIPTION
• Reniform
• Generally smaller
• In almost one-half of reported cases, the
collecting system is severely dilated with thin
parenchyma, suggesting obstruction to the
outflow of urine.
• The ipsilateral and contralateral kidneys are
usually normal
42

Ureteral interrelationships
• Variable
• “a bud off of a bud” situation
– Convergence of the ipsilateral ureters distally to
form a common stem and a single ureteral orifice
– occurs in 50% of cases
• a
43

• “a bud off of a bud” situation
44

• Two completely independentureters, each with its own entrance into the bladder,
are seen in the other 50% of cases
45

Weigert-Meyer principle
• usually followed
• 10% of cases, the caudal kidney has a ureter
that does not follow the rule and enters the
trigone below the ipsilateral ureter
46

Vascular supply
• anomalous
• depends on its position in relation to the
major ipsilateral kidney
• should be separate to be considered a true
supernumerary kidney
47

48

Associated Symptoms
• rarely symptomatic
• may become symptomatic in early adulthood.
• The average age at diagnosis is 36 years.
• Pain, fever, hypertension, and a palpable
abdominal mass are the usual presenting
complaints.
• Urinary infection, obstruction, or both, are the
major conditions that lead to evaluation.
49

Associated Symptoms
• Ureteral ectopia from the supernumerary kidney
may produce urinary incontinence, but this is
extremely rare.
• A palpable abdominal mass secondary to a
carcinoma in the supernumerary kidney has been
described in two patients.
• In 25% of all reported cases, the supernumerary
kidney is discovered only at autopsy
50

DIAGNOSIS
• Incidental on imaging
• USG: In case of obstruction from a stone
– Distortion of the normal ipsilateral kidney and ureter.
– If the collecting system is bifid, the dominant kidney
on that side will usually be involved in the same
disease process.
– If the ureters are separate, the ipsilateral kidney may
show the effects of an abnormal supernumerary
kidney.
51

• Magnetic resonance urography (MRU) and retrograde
pyelography
– needed to delineate the anomaly
• Radionuclide imaging
– relative function in the supernumerary and the normal
kidneys
• Cystoscopy
– reveals one or two ureteral orifices on the ipsilateral side,
depending on whether the ureters are completely
duplicated.
• Occasionally not accurately diagnosed until the time of
surgery or at autopsy, or it may mimic a duplication
52

ANOMALIES OF RENAL ASCENT
• Simple Renal Ectopia
• Cephalad Renal Ectopia
• Thoracic Kidney
53

SIMPLE RENAL ECTOPIA
This unit of metanephric tissue and UB migrate cephalad while simultaneously
rotating medially on its long axis
5th week-Growscranially toward the urogenital ridge, and acquires a cap of
metanephric blastema.
End of 4th week- The UB arises from the WD
Origin- Pelvis, ascends to its usual location in a predictable timeframe
54

The precise mechanism for this ascent remains unknown
Kidney resides in its usual location in the lumbar
retroperitoneum below the adrenal glands.
Between 6 and 9 weeks- The entire process of renal ascent
is completed
55

• Renal ectopia: When the mature kidney fails
to reach its normal location
• Derived from the Greek words
– ek (“out”) and topos (“place”)
– Literally means “out of place.”
56

• An ectopic kidney can be found in one of the
following positions:
– Pelvic
– Iliac
– Abdominal
– Thoracic
– contralateral or crossed
57

Purported factors that may influence the orderly
ascent and rotation
• UB maldevelopment
• defective metanephric tissue that fails to
induce ascent
• genetic abnormalities
• maternal illnesses
• Teratogenic cause
58

• A vascular barrier that prevents upward
migration secondary to persistence of the fetal
blood supply has also been postulated
• But the existence of an “early” renal blood
supply does not prevent the affected kidney’s
movement to its ultimate position.
• The aberrant blood supply is probably an
observed end result, not the cause, of the
renal ectopia
59

Incidence
• Incidence: 1 in 500 to 1 in 1200.
• No gender difference
• Left side more
• Bilateral ectopic kidneys- 10%
60

DISCRIPTION:
• Smaller than its orthotopic counterpart
• Persistent fetal lobulations, may not conform
to the usual reniform shape.
• Adrenal gland is not expected to be absent or
abnormally positioned as renal ascent does
not influence adrenal gland development.
• Rotation and axis of the kidney is also
frequently affected
61

• When ectopia occurs below the diaphragm, the
classification of ectopia is based on the position of the
kidney.
• The pelvic kidney
– lies opposite the sacrum
– kidneys below the aortic bifurcation- M/C site of ectopia
• The lumbar kidney
– resides near the sacral promontory in the iliac fossa and
anterior to the iliac vessels
• Abdominal kidney
– above the iliac crest and is adjacent to the second lumbar
vertebra
62

63

Rotation and axis
• The renal pelvis is usually anterior to the
parenchyma, because the kidney has
incompletely rotated.
• The axis of the ectopic kidney:
– slightly medial or vertical
– may be tilted as much as 90 degrees laterally so
that it lies in a true horizontal plane
64

Hydronephrosis:
• As a result of these anomalies of ascension
and rotation
• Causes:
– 25% from reflux grade III or greater
– 25% from the malrotation alone
– 50% from obstruction
• Ureteropelvic junction- 70%
• ureterovesical junction-30%
65

• Reflux has been reported in approximately
30% to 50%
• The ureter associated with the ectopic renal
unit usually enters the bladder on the
ipsilateral side with its orifice positioned
normally, except for those unusual cases with
ectopic ureters.
66

Vascularity:
• Vascular pattern depends on the ultimate position of the
kidney
• There may be one or two main renal arteries arising from
– the distal aorta or
– aortic bifurcation,
• With one or more aberrant arteries emanating from the
– common or external iliac or
– inferior mesenteric artery.
• The kidney may be supplied entirely by multiple anomalous
branches.
• Exact delineation of the anomalous blood supply can be
pursued with CT/MR imaging or formal angiography when
necessary and can be helpful before surgical intervention
67

Reproductive structure anomalies
• Females:
– bicornuate or unicornuate uterus with atresia of
one horn
– rudimentary or absent uterus and proximal and/
or distal vagina
– duplication of the vagina
68

Reproductive structure anomalies
• Males:
– Hypospadias
– undescended
– duplication of the urethra
69

• The diagnosis of an ectopic kidney is made when
– renal imaging modality fails to show a kidney in its orthotopic location
– reniform tissue is identified in the lower abdomen or pelvis
70

• May become symptomatic
– vague abdominal pain
– renal colic secondary to an obstruction, or
hematuria.
– Urinary tract infection (UTI)
– palpable abdominal mass
71

• DMSA scanning and/or MRU
– may be necessary to diagnose in very small and/or
dysplastic with essentially no function
• Cystoscopy
– usually will reveal ureteral orifices that are
invariably normal unless the ureteral orifice is also
ectopic.
72

• Hydronephrosis or stones
– anteriorly placed pelvis and malrotation of the
kidney
– impair drainage of urine from a high insertion of
the ureter to the pelvis
– anomalous vasculature that partially obstructs
one of the major calyces or the upper ureter.
• Increased risk for injury from blunt abdominal
trauma, because the low-lying kidney is not
protected by the rib cage
73

CONGENITAL ANOMALIES OF KIDNEY
• ANOMALIES OF RENAL NUMBER
• ANOMALIES OF RENAL ASCENT
• ANOMALIES OF RENAL FORM AND FUSION
• ANOMALIES OF RENAL ROTATION
• ANOMALIES OF THE RENAL VASCULATURE
• ANOMALIES OF THE RENAL COLLECTING
SYSTEM
74

CEPHALAD RENAL ECTOPIA
kidneys are positioned immediately beneath the diaphragm near the level of the 10th thoracic vertebra
Diaphragm arrests their ascent.
Allow the kidneys to continue ascension until T 10
Liver herniates into the omphalocele with the intestines
Occur when there is an omphalocele
• Positioned more craniad than normal in a subdiaphragmatic position
75

CEPHALAD RENAL ECTOPIA
• Immediately
beneath the
diaphragm near
the level of the
T10 vertebra
• Ureter- longer.
Normal
• Origin of each
renal artery is
more cephalad
than normal
76

THORACIC KIDNEY
• Intrathoracic ectopia denotes either a partial
or a complete protrusion of the kidney above
the level of the diaphragm into the posterior
mediastinum.
77

THORACIC KIDNEY
Incidence
• 1 : 13,000
• left-sided predominance of 1.5 : 1
• sex ratio favors males by 2 : 1
78

THORACIC KIDNEY
Mesenchymal tissues associated with this membrane eventually form the
muscular component of the diaphragm.
which separates the pleural from the peritoneal cavity.
the diaphragmatic leaflets are formed as the pleuroperitoneal membrane
End of 8 weeks’ gestation- Kidney reach its typical location
79

THORACIC KIDNEY
• Two possibilities exist for the occurrence of an
ectopic intrathoracic kidney:
– either delayed closure of the diaphragmatic
anlage allows for protracted renal ascent above
the level of the future diaphragm
– the kidney overshoots its usual position because
of accelerated ascent before normal
diaphragmatic closure
80

THORACIC KIDNEY
Vasculature
• normal site or a more cranial origin
81

THORACIC KIDNEY
Description
• The kidney is situated in the posterior mediastinum
and usually has completed the normal rotation
process.
• The renal contour and collecting system are normal.
• Thoracic kidney has been described in four basic
categories:
– (1) true ectopia
– (2) diaphragm eventration
– (3) diaphragmatic hernia
– (4) traumatic diaphragm injuries
82

THORACIC KIDNEY
Description
• The kidney usually lies in the posterolateral aspect of
the diaphragm in the foramen of Bochdalek.
• At this point, the diaphragm thins out and a flimsy
membrane surrounds the protruding portion of kidney.
• Therefore the kidney is not within the pleural space
• The lower lobe of the adjacent lung may be hypoplastic
secondary to compression by the kidney mass.
• The renal vasculature and the ureter enter and exit
from the pleural cavity through the foramen of
Bochdalek.
83

THORACIC KIDNEY
Associated Anomalies
• The ureter is elongated to accommodate the
excessive distance to the bladder
• The adrenal gland typically occupies its
normal location
– However, cases of ectopic adrenal glands in
association with thoracic kidneys have been
described
• Contralateral kidney is usually normal.
84

THORACIC KIDNEY
Symptoms
• The vast majority of affected individuals are
asymptomatic.
• Flank pain was the presenting symptom in a
case of UPJ obstruction in a thoracic kidney
• Respiratory symptoms have led to the
diagnosis of intrathoracic kidney
• Renal function is typically normal
85

THORACIC KIDNEY
Diagnosis
• Chest radiograph
– affected hemidiaphragm slightly elevated.
– A smooth, rounded mass is seen extending into the
chest near the midline on AP veiw and along the
posterior aspect of the diaphragmatic leaflet on a
lateral view.
• A thoracic kidney may be found at the time of
thoracotomy for a suspected mediastinal tumor
• CT or MRU is currently the imaging modality of
choice
86

THORACIC KIDNEY
Prognosis
• Neither autopsy series nor clinical reports
suggest that a thoracic kidney will inevitably
lead to serious urinary or pulmonary
complications.
• Therefore surgical intervention is reserved for
clinical signs and/or symptoms.
87

ANOMALIES OF RENAL FORM & FUSION
• Crossed Renal Ectopia With and Without
Fusion
• Horseshoe Kidney
88

Crossed Renal Ectopia With and
Without Fusion
• When a kidney is located on the side opposite
that in which its ureter inserts into the
bladder
• Ninety percent of crossed ectopic kidneys are
fused to their ipsilateral mate.
• Crossed renal ectopia accounts for the second
most common renal fusion anomaly after
horseshoe kidney
89

Without Fusion
McDonald and McClellan in 1957 proposed the
categorization of crossed renal ectopia into four
groups:
90

Without Fusion
• When crossed renal ectopia with fusion
occurs, the fusion anomalies are designated as
91

Without Fusion
INCIDENCE
• 1 in 1000 live births
• Males- 2 : 1
• Left-to-right ectopia is seen three times more
frequently than right-to-left ectopia
92

Without Fusion
EMBRYOLOGY
• Unknown
• Cook and Stephens postulate
– crossover is the result of malalignment and
abnormal rotation of the caudal end of the
developing fetus
• Teratogenic factors
• Genetic influences
93

Without Fusion
• Fusion of the metanephric masses can occur in
the true pelvis before or at the start of cephalad
migration, or it may occur during the latter stages
of ascent
• Structures that might impede advancement of
the kidneys toward their normal location after
fusion
– midline retroperitoneal structures
– the aortic bifurcation
– the inferior mesenteric artery
– the base of the small bowel mesentery.
94

Without Fusion
Ureter
• Crosses the
midline at
the pelvic
brim, S2
vertebra and
enters the
bladder on
the
contralateral
side
95

INFERIOR ECTOPIC KIDNEY
• Two-thirds of all
unilaterally
fused kidneys
involve inferior
ectopia.
• Both renal
pelves are
anterior, so
fusion probably
occurs relatively
early
96

Cake, or Lump, Kidney
• Rare form of fusion
• The total kidney is
irregular and lobulated,
• Ascent usually
progresses only as far as
the sacral promontory,
but in many instances
the kidney remains
within the true pelvis
• Associated with
reproductive
malformations
97

Symptoms
• Most individuals with crossed ectopic
anomalies present no symptoms
• When symptoms occur
– usually develop in the third or fourth decade of
life
– include vague lower abdominal pain, pyuria,
hematuria, and UTI
98

• Stone in a crossed ureter
– causes colic, the pain is lateralized to the anephric
side or the side of the embryonic origin of the ureter,
• Pyelonephritis or obstruction at the UPJ in the
crossed kidney
– the lumbar pain is on the side of the kidneys
• These observations suggest ureteral, not renal,
migration as a causative factor in crossed ectopia
99

Diagnosis
• USG
• Nuclear scans
– to identify functioning renal tissue
• Multidetector three-dimensional CT urography
– for delineating the renal parenchyma, collectingsystem, ureters, and
vascular supply
• MRU, MRA
– performed in children undergoing extensive surgery on an ectopic
kidney to obtain more information while minimizingradiation
exposure.
• Cystoscopy and retrograde pyelography
– useful in mapping the collecting system and pattern of drainage when
MRU does not provide sufficient anatomic detail
100

Prognosis
• Most individuals with crossed renal ectopia
have normal longevity.
• However, those with an obstructive-appearing
collecting system are at risk for development
of UTI, renal calculi, or both
101

HORSESHOE KIDNEY
• Most common of all renal fusion anomalies.
• The anomaly consists of
– two distinct renal masses lying vertically on either
side of the midline and
– connected at their respective lower poles by a
parenchymatous or fibrous isthmus that crosses
the midplane of the body
102

HORSESHOE KIDNEY
Incidence
• 1 in 400 individuals
• Males- 2 : 1
103

HORSESHOE KIDNEY
Description
• In 95% of cases- kidneys join at the lower pole, which
occurs before the kidneys have rotated on their long
axes.
– In a small subset, an isthmus connects both upper poles
• The pelves and ureters of the horseshoe kidney are
usually anteriorly placed, crossing ventrally to the
isthmus.
– Very rarely, the pelves are anteromedial, suggesting that
fusion occurred after some rotation occurred.
• cephalad migration is usually incomplete, and it is
thought that the inferior mesenteric artery prevents
full ascent
104

HORSESHOE KIDNEY
The isthmus
• Generally bulky and consists of parenchymatous tissue
with its own blood supply
• Occasionally- flimsy midline structure composed of
fibrous tissue that tends to draw the renal masses close
together.
• L3 or L4 vertebra just below the origin of the inferior
mesenteric artery from the aorta.
• Most often lies anterior to the aorta and vena cava
– but it has been reported to pass between the inferior vena
cava and the aorta or even behind both great vessels
105

HORSESHOE KIDNEY
The calyces
• normal in number and are atypical in
orientation.
• the calyces point posteriorly, and the axis of
each pelvis remains in the vertical or obliquely
lateral plane
• The lowermost calyces extend caudally or
even medially to drain the isthmus and may
overlie the vertebral column
106

HORSESHOE KIDNEY
Vasculature
• There is tremendous variability to the origin of renal
vasculature to a horseshoe kidney.
• Not infrequently, branches from
– the inferior mesenteric
– common or external iliac
– sacral arteries supply this area
• The blood supply to the isthmus and lower poles is also
variable.
• The isthmus and adjacent parenchymal masses
– might receive a branch from each main renal artery, or
– they may have their own arterial supply from the aorta
originating either above or below the level of the isthmus
107

HORSESHOE KIDNEY
Associated Anomalies
• Gastrointestinal and vertebral anomalies were
the most common
• VATER
• 60% of females with Turner syndrome
• Genitourinary anomalies
– Hypospadias and undescended testes occurred in 4%
of the males
– a bicornuate uterus, a septate vagina, or both were
noted in 7% of the females.
– VUR- 8% to 32%
108

HORSESHOE KIDNEY
• Hydronephrosis secondary to UPJ obstruction
ranges from 13% to 34%
• Hydronephrosis can be secondary to nonrefluxing
and nonobstructing etiology
• UPJ obstruction can be caused by a variety of
factors
– High insertion of the ureter into the renal pelvis
– its abnormal course anterior to the isthmus
– extrinsic compression from the anomalous blood
supply to the kidney may individually or collectively
contribute to the hydronephrosis
109

HORSESHOE KIDNEY
Calculus disease
• Estimated incidence of 36%
• Calcium-based stones are the most prevalent
• Metabolic stone evaluation
– Hypovolemia, hypercalciuria, and hypocitraturia
were the most common metabolic defects
110

HORSESHOE KIDNEY
Symptoms
• At least 50% with horseshoe kidneys are asymptomatic
• When present, symptoms are typically related to
– hydronephrosis, infection, tumor, or calculus formation.
• The most common symptom is vague abdominal pain
that may radiate to the lower lumbar region.
• UTIs occur in 30% of patients, and calculi have been
noted in 20% to 80%
• A horseshoe kidney may present as a palpable
abdominal mass with or without hydronephrosis
111

HORSESHOE KIDNEY
Diagnosis and Radiographic Appearance
• Plain radiograph of the abdomen
– kidneys that are somewhat low lying
– close to the vertebral column
– vertical or outward axis with the lower poles being
more medial than in the normal kidney
112

HORSESHOE KIDNEY
Diagnosis and Radiographic Appearance
• Ultrasound
– diagnosis is made by scanning horizontally along the
midline in a craniocaudal direction
– detects the isthmus joining the two lower poles of the
kidneys in the midline
USG demonstratesthe isthmus (arrow), which is only partially visible anterior to the spine
113

HORSESHOE KIDNEY
• Radionuclide scanning
– demonstrates the abnormal axis of a horseshoe
kidney.
– A continuous band across the midline is observed
if the isthmus contains functioning parenchyma.
114

HORSESHOE KIDNEY
• CT and MRU
– used to characterize the isthmus and further
evaluate hydronephrosis
– to delineate the vascular anatomy for
preoperative planning
115

HORSESHOE KIDNEY
Prognosis
• Kidney cancers
– Renal cell carcinoma
• accounts for about one-half of renal tumors,
• incidence has been found to be no greater than that in the general
population
• high number of renal cancers arise in the isthmus
– Wilms tumors
• primarilyon the left side
• rarely in the isthmus
• all with favorable histology
• The incidence of Wilms tumor in horseshoe kidneys is 1.76 to 7.93
times higher
116

ANOMALIES OF RENAL ROTATION
• The kidney, as it assumes its final position in
the “renal” fossa, orients itself so that the
calyces point laterally and the pelvis faces
medially.
• When this alignment is not exact, the
condition is known as malrotation
• Abnormalities of renal ascent and/or fusion
are typically accompanied by abnormalities of
renal malrotation
117

Incidence
• 1 of 939 autopsies
• frequently observed in association with Turner
syndrome
• Males are affected twice as often as females
• No predilection for side.
118

The kidney starts to turn during the sixth week,
just when it is leaving the true pelvis
completesthis process by rotating 90 degrees
toward the midline by the time ascent is complete
at the end of 9 weeks’ gestation.
The kidney and renal pelvis normally rotate 90
degrees ventromediallyduring ascent
It is thought that medial rotation of the collecting
system occurs simultaneouslywith renal migration
119

120

Ventral Position
• The pelvis is ventral
and in the same
anteroposterior
plane as the calyces
point dorsally
because they have
undergone no
rotation at all.
• This is the most
common form of
malrotation
121

Ventromedial Position
• The pelvis faces
ventromedially
• incompletely rotated
kidney.
• Excursion probably
stops during the
seventh week of
gestation
• The calyces thus
point dorsolaterally
122

Dorsal Position
• Renal excursion of
180 degrees occurs
to produce this
rarest position.
• The pelvis is dorsal
to the parenchyma,
and the vessels pass
behind the kidney to
reach the hilum.
123

Lateral Position
• When the kidney and pelvis
rotate between 180 degrees
and 360 degrees, or
• when reverse rotation of up to
180 degrees occurs
• the pelvis faces laterally and
the kidney parenchyma resides
medially.
• The renal vascular supply
provides the only clue to the
actual direction of excursion.
• Vessels that course ventral to
the kidney to enter a laterally
or dorsolaterally placed hilum
suggest reverse rotation
• whereas a path dorsal to the
kidney implies excessive
ventral rotation
124

125

Symptoms
• Rotation anomalies, per se, do not produce
specific symptoms.
• The excessive amount of fibrous tissue encasing
the pelvis, UPJ, and upper ureter, however, may
lead to varying degrees of hydronephrosis.
• Vascular compression from an accessory or main
renal artery or distortion of the upper ureter or
UPJ may contribute to intermittent obstruction
126

Diagnosis
• The diagnosis should be considered when a renal
calculus is detected in an abnormal location
• CT, MRU, or retrograde pyelogram
– These studies show the abnormal orientation of the
renal pelvis and calyces
• a flattened and elongated pelvis,
• a stretched superior calyx with blunting of the remaining
calyces
• a laterally displaced upper third of the ureter.
– Bilateral malrotation is not uncommon and may
suggest the diagnosis of a horseshoe kidney
127

Prognosis
• Malrotation does not impair renal function.
Hydronephrosis resulting from impaired
urinary drainage may lead to infection and
calculus formation
128

ANOMALIES OF RENAL VASCULATURE
• Aberrant, Accessory, or Multiple Vessels
• Renal artery aneurysm
• Renal Arteriovenous Fistula
129

Aberrant, Accessory, or Multiple
Vessels
• Multiple renal arteries
– kidney supplied by more than one vessel
originating from the aorta
• Anomalous vessels or aberrant vessels
– arteries that originate from vessels other than the
aorta or main renal artery
• Accessory vessels
– denotes two or more arterial branches supplying
the same renal segment
130

Vessels
Incidence
• 71% and 85% of kidneys- single artery
• Single renal artery – right side more
• True aberrant vessels
– Rare
– Present in
• Renal ectopia, with or without fusion
• Horseshoe kidney
131

Vessels
Renal arterial tree is derived from three groups of primitive vasculature
that coalesce to form the mature vascular pattern for all retroperitoneal structures
cranial group
Consists of two pairs
of arteries dorsal to
the suprarenal gland
Phrenic artery
Middle group
composed of three
pairs of vessels that
pass through the
suprarenal area
Adrenal arteries
Caudal group
four paired arteries
cross ventral to the
suprarenal area
Main renal artery
132

Vessels
The completed process being dependent on the final position of the kidney
By a process of elimination, one primitive renal arterial pair eventually becomes
the dominant vessel
The remaining adjacent arteries assume a progressively more important
function.
During renal migration-this network of vessels selectively degenerates
133

Vessels
• Polar arteries or multiple renal arteries to the
normally positioned kidney
– represent a failure of complete degeneration of all
primitive vascular channels.
• The multiple vessel pattern that has been
described for renal ectopia
– considered as an arrested embryonic state for that
particular renal position
134

Vessels
• The renal artery
usually divides to
form anterior and
posterior divisions.
• The anterior division
supplies roughly the
anterior two-thirds of
the kidney
• Posterior division
supplies the posterior
one-third of the
kidney.
135

Vessels
The vessel to the apical segment has the
greatest variation in origin; it arises from
• Anterior division (44%)
• Junction of the A and P divisions (23%)
• Mainstem renal artery or aorta (23%),
• Post. division of the main renal artery (10%)
136

Vessels
A “fork” pattern with a common branching point
(usually duplicated)
• Most commonly observed extrarenal division and
branching pattern of the main renal artery
• Perihilar branching of the main renal artery-
highly variable
• Predictable patterns in the majority of kidneys.
• This information is useful for the transplant
surgeon when interpreting radiodiagnostics of
the renal hilum
137

Vessels
• The lower renal segment, however, is often
supplied by an accessory vessel.
• This vessel is usually the most proximal branch
when it arises from the main renal artery or its
anterior division
• However, it may originate directly from the
aorta near the main renal artery, or it may be
aberrant, arising from the gonadal vessel.
138

Vessels
Symptoms
• Result from inadequate urinary drainage at
the site of extrinsic compression on the
collecting system.
• Multiple, aberrant, or accessory vessels may
constrict an infundibulum, a major calyx, or
the UPJ
• Pain and hematuria secondary to
hydronephrosis, UTI, or calculus may result.
139

Vessels
Diagnosis
• Precise anatomic resolution of vascular
variants and associated disease states can be
obtained using
– Three-dimensional power Doppler
ultrasonography
– CT
– MRI
140

Vessels
• CT scan after
administration of
intravenous contrast
demonstrating renal
artery anatomy on
coronal images-
– Arrows point to
two separate renal
arteries arising
from aorta.
• Coronal three-
dimensional
reconstruction
showing single right
renal artery and two
left renal arteries
141

Vessels
142

Vessels
Prognosis
• Hydronephrosis secondary to a vascular
anomaly such as a lower pole crossing vessel
is a very rare finding.
• Hypertension is no more frequent in patients
with multiple renal arteries than in those with
a single vessel
143

RENAL ARTERY ANEURYSM
Abeshouse
classified RAAs
as follows:
Saccular Fusiform Dissecting arteriovenous
• Incidence- 0.09%
• Right side is more commonly encountered
• Bilateral aneurysms are seen in up to 15%
144

• The saccular aneurysm
– a localized outpouching that communicates with
the arterial lumen by a narrow or wide opening
– most common type
– 93% of all aneurysms
• The Fusiform type
– When the aneurysm is located at the bifurcation
of the main renal artery and its anterior and
posterior divisions, or at one of the more distal
branchings
145

When symptoms are present, they include
• Abdominal or flank pain (6% to 15%)
• Hematuria
– microscopic and macroscopic; 5% to 30%
• Hypertension (10% to 55%)
– renin-mediated and secondary to relative
parenchymal ischemia
• Thirteen cases of hydronephrosis secondary to an
adjacent renal vessel aneurysm were noted
146

The diagnosis is suspected when
• Palpation:
– a pulsatile mass is palpated in the region of the renal hilum
• Auscultation:
– when a bruit is heard on abdomen.
• Imaging
– A wreathlike calcification in the area of the renal artery or its
branches (30%) is highly suggestive
– color Doppler sonography, spiral CT, three-dimensional MRA, or
digital subtraction arteriography
– workup of uncontrolled hypertension (35%)
147

Indications for treatment
• Remain controversial
• who present with rupture or are at a high risk for
rupture.
• High risk for rupture
– Rapidly expanding RAAs
– Pregnant females, or those who are considering pregnancy
• Asymptomatic Larger than 2 cm( 3cm: Risk-18%)
• Symptomatic-
– Uncontrolled hypertension from renal artery stenosis
– Flank pain, hematuria, or renal ischemia/infarction
resulting from embolization from the aneurysm 148

RENAL ARTERIOVENOUS FISTULA
• Less than 25% of all AVFs are congenital
– Only 91 reported cases
• They are identifiable by their cirsoid
configuration and multiple communications
between the main or segmental renal arteries
and the venous channels
• They rarely present clinically before the 3rdor 4th
decade.
• Women- three times more often
• Right kidney- slightly more
149

• Location
– upper pole (45% of cases)
– midportion (30%)
– lower pole (25%) of the kidney
• Etiology
– either present at birth or
– to result from a congenital aneurysm eroding into
an adjacent vein
150

• The pathophysiology
– shunting of blood, which bypasses the renal parenchyma
and rapidly joins the venous circulation and returns to the
heart
• The symptoms are based on the age and size of the
AVF
• The hemodynamic derangement often produces a loud
bruit in 75% of cases.
• Diminished perfusion of renal parenchyma distal to the
fistulous site leads to relative ischemia and renin-
mediated hypertension in approximately 50%
151

LVH and subsequenthigh-output
cardiac failure in 50% of cases
diminution
in
peripheral
resistance
high
cardiac
output
Increased
venous
return
152

• Macroscopic and microscopic hematuria
– 75% of affected individuals
– Because of the proximity of the collecting system
• Flank or abdominal pain may be present
• Mass is rarely palpable (10%)
153

Diagnosis
• Selective renal arteriography or DSA
• Most definitive method for diagnosing the
lesion.
• Pathognomonic features
– A cirsoid appearance
– multiple small, tortuous channels
– prompt venous filling
– enlarged renal, and possibly gonadal, vein
154

• The symptomatic nature of this lesion, which
causes progressive alterations in the
cardiovascular system, often dictates surgical
intervention.
• The congenital variant rarely behaves like its
acquired counterpart, which may disappear
spontaneously after several months
155

Treatment options
• Nephrectomy
• Partial nephrectomy
• Vascular ligation
• Selective embolization
• Balloon catheter occlusion
156

ANOMALIES OF THE RENAL COLLECTING SYSTEM
• Bifid Pelvis
• Calyceal Diverticulum
• Hydrocalycosis
• Megacalycosis
• Infundibulopelvic Stenosis
157

BIFID PELVIS
• 10% of normal renal pelves are bifid,
• Pelvis dividing to form two major calyces first
at, or just within, its entrance to the kidney.
• A bifid pelvis should be considered a normal
variant.
• Further division of the renal pelvis can occur
resulting in triplication of the pelvis, but this is
extremely rare
158

BIFID PELVIS
• Sonogram showing split
hyperechoic region of
renal sinus indicative of
bifid renal pelvis.
• Cystogram
demonstrating bilateral
vesicoureteral reflux
into bifid renal pelves
159

CALYCEAL DIVERTICULUM
• Cystic cavity within the kidney that is lined by
transitional epithelium and communicates
with a calyx or, less commonly, with the renal
pelvis through a narrow isthmus.
• An incidence of 4.5 per 1000
• Infection, stone formation are complications
of stasis or obstruction that can produce
symptoms
160

• The diagnosis of calyceal diverticulum is best
made by CT or MRU.
• Patients who are asymptomatic do not require
treatment but should be followed periodically
with ultrasonography
• Endoscopic or laparoscopic treatment are
both effective approaches for treatment of
symptomatic calyceal diverticulum
161

• Indications for surgery
– enlargement of the diverticulum associated with
• pain or infection
• abscess formation
• urosepsis
– symptomatic calculus formation
162

Surgical Approaches
• Ureteroscopy
– enlargement of the diverticular communication
and removal of the stones has also been reported
– ablation of the diverticular cavity to minimize the
risk for recurrence
• Percutaneous ablation of the communication
and fulguration of the diverticular lining is a
viable option with favorable long-term results
163

• Ultrasound of a hypoechoic lesion in the
upper pole of the left kidney and no
significant hyperemia surrounding the cystic
lesion.
164

• Magnetic resonance axial image of the left kidney
precontrast compared with 5 minutes post–intravenous
contrast. Images show in upper pole of the left kidney a 3-
cm cystic lesion with layering internal contents.
165

• Retrograde pyelogram demonstrating injection of contrast
into the left ureter and left renal collecting system
opacifying the nondilated collecting system and a rounded
collection of contrast superior to the collecting system,
which was a calyceal diverticulum.
166

HYDROCALYCOSIS
• Hydrocalycosis is a rare cystic dilation of a major
calyx with a demonstrable connection to the
renal pelvis
• Cicatrization of an infundibulum may result from
infection or trauma or without an obvious
• It has been postulated that achalasia of a ring of
muscle at the entrance of the infundibulum into
the renal pelvis causes a functional obstruction
• most frequent presenting symptom is upper
abdominal or flank pain
167

MEGACALYCOSIS
• Megacalycosis is defined as nonobstructive
enlargement of calyces resulting from
malformation of the renal papillae
• Males- 6 : 1, only in Caucasians.
• Bilateral disease has been seen almost
exclusively in males
• whereas segmental unilateral involvement
occurs only in females
168

MEGACALYCOSIS
The increased number of calyces may be an aborted response by the branching
UB to the obstruction.
The fetal calyces may dilate and retain their obstructed appearance, despite the
lack of evidence of obstruction in postnatal life
This produces transient obstruction when the glomeruli start producing urine.
Transientdelay in the recanalization of the upper ureter after the branches of the
UB hook up with the metanephricblastema
169

MEGACALYCOSIS
• Usually diagnosed during radiographic evaluation for
UTI or other congenital anomalies
• Adults frequently present with hematuria secondary to
renal calculi.
• The calyces are dilated and are usually increased in
number, but the infundibuli and pelvis may not be
enlarged
• Diuretic renography shows a normal pattern for uptake
and washout of the isotope
• Long-term follow-up of these patients does not show
progression of the anatomic derangement or
functional impairment of the kidney
170

MEGACALYCOSIS
• Voiding cystogram demonstrating bilateral vesicoureteral reflux, right
grade 1 and left side with innumerable dilated calyces and nondilated
renal pelvis diagnostic of megacalycosis
171

INFUNDIBULOPELVIC STENOSIS
• Infundibulopelvic stenosis most likely forms a
link between cystic dysplasia of the kidney and
the grossly hydronephrotic organ
• This condition includes a variety of
radiographically dysmorphic kidneys with
varying degrees of infundibular or
infundibulopelvic stenosis that may be
associated with renal dysplasia
172

• It is believed that this was the result of
extensive dysgenesis of the pyelocalyceal
system but with preservation of renal
function.
• Infundibulopelvic stenosis is usually bilateral
and is commonly associated with
vesicoureteral reflux, suggesting an
abnormality of the entire UB
173

• Patients usually present with urinary infection,
hypertension, or flank pain.
• Sometimes, an asymptomatic child with multiple
anomalies is found to have this condition
• Despite extensively dysmorphic kidney features,
the function is either normal or only slightly
affected
• Decreased total functional renal tissue leads to
hyperfiltration injury
174

Right kidney
ascending
pyelography.
• Several points
of infundibular
stenosis and
calyceal
dilatation, as
well as pelvic
dilatation, are
observed.
• The arrow
points to
severe
infundibular
stenosis at the
middle calyx
175

Endoscopic image of
stenotic
infundibulum in the
middle calyx of the
right kidney.
176

• Monitoring of renal function to include
– a baseline and yearly serum creatinine level
– estimation of glomerular filtration rate
– urinalysis
• Prevention of hyperfiltration injury with
– calcium channel–blocking agents
– ACE inhibitors
– dietary restriction of protein should be considered when a
decline in renal function occurs.
• Surgical intervention should be reserved for patients in
whom obstruction from the infundibulopelvic stenosis
is demonstrated to negatively affect renal function.
177

THANK YOU
178

Congenital anomalies of kidney.

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