This presentation comprises of congenital anomalies of kidney and urinary tract made concise and in depth for PG preparation. It contains all important topics of the regarding subject covered in detail.
• Normal renal development is dependent upon the interaction
between the ureteric bud and metanephric mesenchyme, which
induces organogenesis resulting in the formation of nephrons and
collecting system of each kidney.
• Note: The neonatal kidney achieves concentrating ability equivalent
to adult’s kidney by the age of 1 year.
Common congenital renal anomalies
• The following renal malformations arise when this process is disrupted:
i. Renal agenesis — Congenital absence of kidney(s).
ii. Renal hypoplasia — Congenitally small kidneys with a reduced number
of nephrons but normal architecture.
iii. Renal dysplasia — The presence of malformed renal tissue elements,
including primitive tubules, interstitial fibrosis +/ the presence of
cartilage in the renal parenchyma.
iv. Renal hypodysplasia — Congenitally small kidney with dysplastic
features. Renal hypoplasia is more commonly associated with dysplasia
• Unilateral renal agenesis is much more common than bilateral one.
• Malformations associated with unilateral renal agenesis:
1. Single umbilical artery
2. Absent ureter
3. Absent ipsilateral vas deferens
4. Contralateral vesico-ureteral reflex.
Bilateral renal agenesis/ Potter syndrome
• Potter syndrome= Bilateral renal agenesis + Pulmonary agenesis +
• Potter facies= Widely separated eyes + epicanthic folds + broad
compressed flat nose.
• Death occurs shortly after birth pulmonary hypoplasia.
• Maternal USG demonstrates:
Absence of kidney
Non-visualization of bladder.
• The diagnosis of unilateral renal hypoplasia is usually incidental.
• When it is bilateral, it usually presents with signs and symptoms of
chronic renal failure.
Signs and symptoms of chronic kidney disease
• Early symptoms: Polydipsia and nocturia
• Symptoms of advanced chronic kidney disease in children:
Bone disease (termed renal osteodystrophy)
Anorexia, nausea, vomiting.
• Signs of advanced chronic kidney disease in children:
• Multicystic dysplastic kidney (MCDK) is the most common cystic
disease in infants.
• It is also the most common cause of abdominal mass in neonates;
although the mass is non-palpable at birth in majority of cases.
• MCDK is a congenital condition, in which the kidney is replaced by
cysts and the entire kidney is dysplastic; so it does not function.
• It is usually unilateral (also called unilateral renal dysplasia).
• When it is bilateral, it is incompatible with life.
• Risk of Wilm’s tumor arising from an MCDK is approx. 1/333.
Horse shoe kidney
• It is a developmental anomaly where there is failure of complete ascent of
kidneys with the fusion of lower or upper poles. It is due to fusion of
subdivisions of mesonephric duct.
• Salient points:
Common in males
Seen in 7% of patients with Turner’s syndrome
Fusion of lower pole is common
Commonest site is in front of 4th lumbar vertebrae.
• Presents as a fixed, nonmobile, firm mass in the midline at the level of 4th
lumbar vertebra which is resonant on percussion.
• Treatment: Complications are treated accordingly.
Uncommon congenital diseases of
kidney and urinary tract
• Nephronophthisis is the most common genetic cause of ESRD in children
and young adults.
• Nephronophthisis is a genetic disorder characterized by development of
fluid-filled cysts in the corticomedullary region; followed by inflammation
and fibrosis that impairs kidney function.
• Symptoms and signs:
Growth +/ mental retardation.
• Nephronophthisis eventually leads to end-stage renal disease (ESRD).
• Nephronophthisis can be classified by the approximate age at which
Around age 1 (infantile),
Around age 13 (juvenile), and
Around age 19 (adolescent).
Medullary cystic kidney disease (MCKD)
• Medullary cystic kidney disease (MCKD) and nephronophthisis (NPH)
refer to 2 inherited diseases with similar renal morphology [bilateral
small corticomedullary cysts in kidneys of normal/ reduced size and
tubulointerstitial sclerosis leading to ESRD].
• These disorders have traditionally been considered as parts of a
complex (the NPH complex) because they share many of the clinical
and histopathological features.
• The major differences are in the modes of inheritance, the age of
onset of ESRD and the extrarenal manifestations.
Mode of inheritance Autosomal recessive Autosomal dominant
Age of onset of ESRD Around age 1 (infantile)
Around age 13 (juvenile)
Around age 19 (adolescent)
Extrarenal manifestations In 10% of cases:
Growth and mental retardation
• Positive family history in 60% of cases
• Prenatal diagnosis: Enlarged kidneys, H/O oligohydramnios
• Children: Asymptomatic; incidental detection of renal cysts in USG
• 2nd decade of life: Episodic hematuria and hypertension, bilaterally
palpable kidneys, hepatic cysts (asymptomatic).
Coarctation of aorta
Mitral valve prolapse
Non-opioid analgesics to control pain
Surgical/ percutaneous drainage of cysts to control pain/ infection
Nephrectomy in case of intractable symptoms/ symptoms due to
mass effect of enlarged kidneys
Dialysis: Hemodialysis/ peritoneal dialysis
Renal transplantation in ESRD patients
Special note: Newer drug: Tolvaptan, a vasopressin receptor 2 (V2)
• A ureterocele is a cystic out-
pouching of the distal ureter
into the urinary bladder.
• Ureterocele occurs due to a
combination of an abnormality
in the submucosal part of ureter
and stenosis of ureteric orifice.
According to renal collecting system:
1. Single-system ureteroceles: Those
associated with a single kidney,
collecting system and ureter.
2. Duplex-system ureteroceles: Those
associated with kidneys that have
completely duplicated ureters.
According to position of ureteric orifice:
1. Orthotopic (intravesical) ureterocele is a
term used for a ureterocele contained
within the bladder.
2. Ectopic (extravesical) ureterocele refers to
ureteroceles with tissue that originates at
the bladder neck or beyond, into the
• Currently, most pediatric ureteroceles are found during routine
• Complications include: infection/ obstruction/ stone formation/
urinary incontinence/ acute bladder neck obstruction.
• Presence of filling defect in micturating cysto-urethrogram (MCU) is
the most characteristic diagnostic finding of ureterocele.
• Intravenous urography (IVU): Cobra head appearance [of historical
• Cystoscopic ureteric meatotomy with the removal of cyst wall
• Often ureteric reimplantation is needed.