kidney_and_ureters.ppt

Kidney and Ureters :
Agenesis, Horseshoe kidneys,
congenital cysts, Megaureter,
Ectopic ureter, Ureterocele
Dr Amit Gupta
Associate Professor
Dept Of Surgery

Bilateral Renal Agenesis
• Bilateral Renal Agenesis was first recognized in 1671 by Wolfstrigel
• Can occur secondary to a defect of the wolffian duct, ureteric
bud, or metanephric blastema
• Bilateral agenesis occurs in 1 of every 4000 births
• Male predominance

• 40% of the affected infants are stillborn
• Children who are born alive do not survive beyond 48 hours
because of respiratory distress associated with pulmonary
hypoplasia
• The adrenal glands are usually normally positioned
• Characteristic Potter facies and presence of oligohydramnios are
pathognomonic
• Complete ureteral atresia is observed in slightly more than 50%
of affected individuals

Diagnosis
• The characteristic Potter facies and the presence of
oligohydramnios are pathognomonic and should alert for
this severe urinary malformation.
• Amnion nodosum—small white, keratinized nodules found
on the surface of the amniotic sac—may also suggest this
anomaly
• Anuria after the first 24 hours without distention of the
bladder should suggest renal agenesis

Diagnosis
• BRA has been detected in higher proportion in
cryptophthalmos or Frazer's syndrome, Klinefelter's syndrome ,
Kallmann's syndrome, esophageal atresia.
• Renal ultrasonography confirm the presence or absence of
urine within these structures.
• Absence of uptake of the radionuclide in the renal fossa above
background activity confirms the diagnosis of BRA.
• Umbilical artery catheterization and an aortogram defines the
absence of renal arteries and kidneys.

Unilateral Renal Agenesis
• There are no tell tale signs (as with BRA) that suggest an
absent kidney .
• Diagnosis not suspected unless careful examination of the
external and internal genitalia uncovers an abnormality
that is associated with renal agenesis or an imaging study is
done.
• Unilateral agenesis occurs once in 1100 births
• Males predominate in a ratio of 1.8:1

• More frequent on the left side
• Ipsilateral ureter is completely absent in about half
of the patients
• Structures derived from the müllerian or wolffian
duct are most often anomalous
• Anomalies of other organ systems involve the
cardiovascular (30%), gastrointestinal (25%), and
musculoskeletal (14%) systems

Unilateral renal agenesis to be associated with other
urologic abnormalities in 48% of patients
– Primary vesicoureteral reflux (28%)
– Obstructive megaureter (11%)
– Ureteropelvic junction obstruction (3%)

Diagnosis
• No specific symptoms heralding an absent kidney
• The diagnosis should be suspected during a physical
examination when the vas deferens or body and tail of the
epididymis is missing or hypoplastic vagina is associated with a
unicornuate or bicornuate uterus
• Radionuclide imaging
• No clear-cut evidence that patients with a solitary kidney
have an increased susceptibility to other diseases

• Most common of all renal fusion anomalies
• Occurs in 0.25% of the population
• fusion occurs before the kidneys have rotated on
their long axis
Horseshoe kidneys

The lower poles of the two kidneys touch and fuse as they cross the iliac arteries

• In 95% of patients, the kidneys join at the lower pole; in a
small number, an isthmus connects both upper poles instead
• Calyces normal in number, are atypical in orientation
• Ureter may insert high on the renal pelvis and lie laterally
• Blood supply to the horseshoe kidney can be quite variable

Arteriogram showing a multiplicity of arteries supplying kidney arising from
aorta and common iliac arteries

• UPJ obstruction, causing hydronephrosis, occurs in
one third of individuals
• 60% patients remain asymptomatic for aprox. 10
years

Diagnosis
• Excretory urogram

Prognosis
• 13% have persistent urinary infection or pain
• 17% develop recurrent calculi
• Renal carcinoma has been reported within a horseshoe
kidney in 123 patients
• Incidence of Wilms' tumor in horseshoe kidneys is more
than twice

Congenital cysts
• Kidney is one of the MC
sites in body for cysts
• Arise from the nephrons
and collecting ducts after
they have formed

• Multicystic refers to a dysplastic entity
• Polycystic most inherited, all without dysplasia and all
with nephrons throughout the kidney
• Many of the polycystic kidney disease entities progress
to renal failure

‘Snowstorm’ appearance of infantile polycystic
disease

Ectopic Kidney
• Kidney not located in usual position
• 1 in 1,000 births, but only about one in 10 of these
are ever diagnosed; up to 10% bilateral
Most common:
– Horseshoe Kidney
– Unilateral renal agenesis
– Pelvic kidney
(Left kidney more likely to be abnormal)

Ectopic Kidney
• Function is generally normal initially
• Abnormal position leads to obstruction in 50% of
ectopic kidneys
• Increased risk UTI, kidney stones, VUR
• Frequently associated with abnormalities of other
organ systems (uterine, cardiac, skeletal)

Ectopic Kidney
(simple renal ectopia)

Mega ureter
• Ureters wider than 7 to 8 mm
• Normal ureteral diameter is rarely greater than 5 mm
• Primary MGU is 2-4 times more common in boys than girls
• Slight predilection (1.6 to 4.5 times) for the left side
• Bilateral in approximately 25% of patients
• In 10% to 15% of children contralateral kidney may be absent or
dysplastic

Three major classifications of megaureter based on primary and secondary causes

Pathophysiology
• Distal end of the ureter, as it becomes intramural and
subsequently submucosal, rearranges the muscular layers in its
wall.
• All layers become longitudinally oriented
• Ureteral adventitia fuses to the bladder trigone by attachment to
Waldeyer's sheath
• Sympathetic and parasympathetic innervation to the distal ureter
and UVJ area is believed to modulate primarily ureteral peristalsis

Diagnosis
Ultrasound
• Distinguishes MGU from UPJ obstruction based on the
presence or absence of a dilated ureter
VCUG
• to rule out reflux
Renal scintigraphy
• Provides objective, reproducible parameters of function
and obstruction

Whitaker's perfusion test & ureteral opening pressure
• To evaluate obstruction, but their invasiveness and
requirement for anaesthesia are drawbacks in children
Magnetic resonance urography

Magnetic resonance urogram showing obstruction at the right ureterovesical junction

Management
Primary Refluxing Megaureter
• Medical management is often the initial approach
• Surgery
– Endoscopic subureteric injection, is recommended for
persistent high-grade reflux in older children
• Reconstructive surgery of a dilated ureter
– distal ureterostomy for unilateral reflux
– vesicostomy for bilateral disease

• Secondary Refluxing or Obstructive Megaureter
– Management of secondary MGUs is initially directed at their
root cause
• Primary “Dilated” Nonrefluxing Megaureter:
Nonobstructive versus Obstructive
– Expectant management is preferred
– Antibiotic suppression & radiologic surveillance is appropriate
in most cases
– Surgical correction

• Surgical Options
– Plication or infolding for moderately dilated ureter
Complications
Persistent reflux and obstruction
Postoperative VUR

Ectopic ureter
• Ureter whose orifice terminates anywhere other
than the normal trigonal position
• Lateral ectopia : an orifice more cranial and lateral
than normal
• Caudal ectopia : orifice is more medial and distal
than the normal position

• 80% are associated with a duplicated collecting system
• Females :
– More than 80% are duplicated
– Urethra and vestibule are the most common sites
• Males:
– most ectopic ureters drain single systems
– posterior urethra is the most common site
• Drainage into the genital tract involves the seminal vesicle three
times more often than the ejaculatory duct and vas deferens
combined

Ureterocele
(outpouching of ureter as it enters bladder)

kidney_and_ureters.ppt

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