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Congenital Anomalies of Kidney & Ureter

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									Congenital Anomalies
     of Kidney
     & Ureter

  Dr. Muhammad Rafique
      Anatomy, DIMC
             Objectives
Know the prevalence of congenital
 anomalies of Kidney & Ureter
Discuss the congenital anomalies of
 Kidney
Describe the congenital anomalies of the
 Renal Vessels
Mention the congenital anomalies of
 Ureter
Congenital
Anomalies
of Kidney
 Congenital Anomalies of Kidneys & Ureters

Some type of abnormality
  of the kidneys and
  ureters occurs in 3% to
  4% of newborn infants.
  Anomalies in shape and
  position are most
  common. Many fetal
  urinary tract
  abnormalities can be
  detected before birth by
  ultrasonography.
        Unilateral Renal Agenesis
Unilateral renal
 agenesis occurs
 approximately 1in
 1000 newborn
 infants. Males are
 affected more often
 than females, and
 the left kidney is
 usually the one that
 is absent.
        Unilateral Renal Agenesis
Unilateral renal agenesis
 often causes no symptoms
 and is usually not
 discovered during infancy
 because the other kidney
 usually undergoes
 compensatory hypertrophy
 and performs the function
 of the missing kidney.
 Unilateral renal agenesis
 should be suspected in
 infants with a single
 umbilical artery
           Bilateral Renal Agenesis
Bilateral renal agenesis is
  associated with
  oligohydramnios (small
  amount of amniotic fluid)
  because little or no urine is
  excreted into the amniotic
  cavity.
This condition occurs
  approximately 1 in 3000
  births, and is incompatible
  with postnatal life because
  of the associated
  pulmonary hypoplasia.
            Bilateral Renal Agenesis
These infants have a
  characteristic facial
  appearance: the eyes are
  widely separated and
  have epicanthic folds,
  the ears are low-set, the
  nose is broad and flat,
  the chin is receding, and
  there are limb defects.
  Most infants with
  bilateral renal agenesis
  die shortly after birth or
  during the first months
  of life.                     Intravenous Pyelography
         Etiology of Renal Agenesis
Renal agenesis results when
  the metanephric
  diverticula fail to develop
  or the primordia of the
  ureters degenerate. Failure
  of the metanephric
  diverticula to penetrate the
  metanephrogenic blastema
  results in failure of kidney
  development because no
  nephrons are induced by the
  collecting tubules to develop
  from the metanephrogenic
  blastema.
         Etiology of Renal Agenesis
Renal agenesis probably
  has a multifactor
  etiology. There is
  clinical evidence that
  complete in utero
  involution of
  polycystic kidneys
  could lead to renal
  agenesis with a blind
  ending ureter on the
  same side.
                 Malrotated Kidney
If a kidney fails to rotate, the
   hilum faces anteriorly, that
   is, the fetal kidney retains
   its embryonic position. If
   the hilum faces posteriorly,
   rotation of the kidney
   proceeded too far; if it
   faces laterally, lateral
   instead of medial rotation
   occurred. Abnormal
   rotation of the kidneys is
   often associated with
   ectopic kidneys.
                Ectopic Kidneys
One or both kidneys may
 be in an abnormal
 position. Most ectopic
 kidneys are located in
 the pelvis but some lie
 in the inferior part of
 the abdomen. Pelvic
 kidneys and other forms
 of ectopia result from
 failure of the kidneys to
 alter position during
 embryo growth.
                     Pelvic kidneys
Pelvic kidneys are close to each
  other and may fuse to form a
  discoid ("pancake") kidney.
  Ectopic kidneys receive their
  blood supply from blood
  vessels near them (internal or
  external iliac arteries and/or
  aorta). They are often
  supplied by multiple vessels.
  Sometimes a kidney crosses to
  the other side resulting in
  crossed renal ectopia showing
  both kidneys on the right side
  of the abdomen).
                    Pelvic kidneys
Sometimes a kidney crosses
  to the other side, resulting
  in crossed renal ectopia
  with or without fusion.
  An unusual type of
  abnormal kidney is
  unilateral fused kidney. In
  such cases, the
  developing kidneys fuse
  while they are in the
  pelvis, and one kidney
  attains its normal
  position, carrying the
  other kidney with it.
                Horseshoe Kidney
In 0.2% of the population,
   the poles of the kidneys are
   fused; usually the inferior
   poles fuse. The large U-
   shaped kidney usually lies
   in the hypogastrium,
   anterior to the lower
   lumbar vertebrae. Normal
   ascent of these fused
   kidneys is prevented
   because they are caught by
   the root of the inferior
   mesenteric artery.
               Horseshoe Kidney
A horseshoe kidney usually
  produces no symptoms
  because its collecting
  system develops normally
  and the ureters enter the
  bladder. If urinary flow is
  impeded, signs and
  symptoms of obstruction
  and/or infection may
  appear. Approximately 7%
  of persons with Turner's
  syndrome have horseshoe
  kidneys.
            Cystic Kidney Diseases
In autosomal recessive
   polycystic kidney disease,
   diagnosed at birth or in
   utero by ultrasonography,
   both kidneys contain many
   hundreds of small cysts,
   which result in renal
   insufficiency. Death of the
   infant usually occurs
   shortly after birth;
   however, an increasing
   number of these infants are
   surviving because of
   postnatal dialysis and
   kidney transplantation.
  Multicystic Dysplastic Kidney Disease
Multicystic dysplastic kidney
 disease results from
 dysmorphology during
 development of the renal system.
 The outcome for children with
 multicystic dysplastic kidney
 disease is generally good because
 the disease is unilateral in 75%
 of the cases. In multicystic
 dysplastic kidney disease, fewer
 cysts are seen than in autosomal
 recessive polycystic kidney
 disease and they range in size
 from a few millimeters to many
 centimeters in the same kidney.
  Multicystic Dysplastic Kidney Disease
For many years it was
  thought that the cysts were
  the result of failure of the
  metanephric diverticulum
  derivatives to join the
  tubules derived from the
  metanephrogenic blastema.
  It is now believed that the
  cystic structures are wide
  dilations of parts of the
  otherwise continuous
  nephrons, particularly the
  nephron loops (loops of
  Henle).
             Multicystic Dysplastic
In the multicystic dysplastic
   kidney the numerous
   ducts are surrounded by
   undifferentiated cells.
   Nephrons fail to develop
   and the ureteric bud fails
   to branch, so that the
   collecting ducts never
   form. In some cases,
   these defects cause
   involution of the kidneys
   and renal agenesis.
                    Renal Tumors
Wilms’ tumor is a cancer of the
 kidneys that usually affects
 children by 5 years of age but
 may also occur in the fetus.
 Wilms’ tumor is due to
 mutations in the WT1 gene on
 11p13, and it may be associated
 with other abnormalities and
 syndromes. For example,
 WAGR syndrome is
 characterized by aniridia,
 hemihypertrophy, and Wilms’
 tumor. Similarly, Denys-Drash
 syndrome consists of renal
 failure, pseudohermaphrodism,
 and Wilms’ tumor.
            Accessory Renal Arteries
The common variations in the
  blood supply to the kidneys
  reflect the manner in which the
  blood supply continually
  changed during embryonic and
  early fetal life. Approximately
  25% of adult kidneys have two
  to four renal arteries.
Accessory (supernumerary)
  renal arteries usually arise
  from the aorta superior or
  inferior to the main renal artery
  and follow the main renal artery
  to the hilum of the kidney.
            Accessory Renal Arteries
Accessory renal arteries may also
  enter the kidneys directly,
  usually into the superior or
  inferior poles. An accessory
  artery to the inferior pole (polar
  renal artery) may cross anterior
  to the ureter and obstruct it,
  causing hydronephrosis-
  distention of the renal pelvis
  and calices with urine. If the
  artery enters the inferior pole of
  the right kidney, it usually
  crosses anterior to the inferior
  vena cava and ureter.
           Accessory Renal Arteries
It is important to be aware
   that accessory renal arteries
   are end arteries;
   consequently, if an
   accessory artery is
   damaged or ligated, the
   part of the kidney supplied
   by it will become ischemic.
   Accessory arteries are
   approximately twice as
   common as accessory
   veins.
Congenital
Anomalies
 of ureter
   Duplications of the Urinary Tract
Duplications of the
 abdominal part of the
 ureter and the renal
 pelvis are common.
 These anomalies result
 from division of the
 metanephric
 diverticulum. The
 extent of the duplication
 depends on how
 complete the division of
 the diverticulum was.
   Duplications of the Urinary Tract
Incomplete division of the
  metanephric diverticulum
  results in a divided kidney
  with a bifid ureter.
  Complete division results in
  a double kidney with a bifid
  ureter or separate ureters. A
  supernumerary kidney
  with its own ureter, which
  is rare, probably results
  from the formation of two
  metanephric diverticula.
                    Ectopic Ureter
An ectopic ureter does not
   enter the urinary bladder.
In males, ectopic ureters
   usually open into the neck
   of the bladder or into the
   prostatic part of the urethra,
   but they may enter the
   ductus deferens, prostatic
   utricle, or seminal gland.
In females, ectopic ureters
   may open into the bladder
   neck, urethra, vagina, or
   vestibule of the vagina.
                  Ectopic Ureter
Incontinence is the
  common complaint
  resulting from an
  ectopic ureter because
  the urine flowing from
  the orifice does not
  enter the bladder;
  instead it continually
  dribbles from the
  urethra in males and the
  urethra and/or vagina in
  females.
                    Megaureter
Megaureter means
 abnormally dilated ureter
This may be congenital or
 acquired
May be primary due to
 disease of renal system or
 secondary to obstruction
 produce by other organs or
 vessels near to renal system
Usually caused by absence
 peristaltic movement in
 smooth muscle of ureter
                  Ectopic Ureter
An ectopic ureter results
  when the ureter is not
  incorporated into the
  trigone in the posterior
  part of the urinary
  bladder. Instead it is
  carried caudally with
  the mesonephric duct
  and is incorporated into
  the middle pelvic
  portion of the vesical
  part of the urogenital
  sinus.
                   Ectopic Ureter
Because this part of the
  sinus becomes the
  prostatic urethra in
  males and the urethra
  in females, the location
  of ectopic ureteric
  orifices is
  understandable. When
  two ureters form on
  one side, they usually
  open into the urinary
  bladder.

								
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