Anomalies of the Upper Urinary Tract
ANOMALIES OF NUMBERBilateral Renal Agenesis
The incidence of BRA is rare. 75% of individuals being male.The characteristic Potter facies (The infants look prematurely senile and have a prominent fold of skin that begins over each eye, swings down in a semi-circle over the inner canthus and extends onto the cheek ,the nose is blunted, and a prominent depression exists between the lower lip and chin. The ears appear to be low set) and the presence of oligohydramnios are pathognomonic.
The legs are often bowed and clubbed, with excessive flexion at the hip and knee joints.
The adrenal glands are usually positioned normally.
Abdominal ultrasonography identifies the presence or absence of kidneys.
Prognosis. About 50% of the affected neonates are stillborn. Of those neonates who are born alive, most do not survive beyond the first 24 to 48 hours due to respiratory distress associated with pulmonary hypoplasia.
Unilateral Renal Agenesis
Unilateral renal agenesis occurs once in 1000 births .more common in males. It more frequently on the left side. A familial tendency has been reported.Abnormalities of the contralateral ureter including ureteropelvic junction obstruction in 10% and vesicoureteral reflux in 30%.Anomalies of Other Organ Systems: Anomalies of other organ systems are found frequently in affected individuals. The more common sites involve the cardiovascular (30%), gastrointestinal (25%).
Diagnosis and Radiographic Evaluation:
- There are no specific symptoms that suggest an absent kidney.
-Abdominal ultrasonography.
-The diagnosis of URA usually can be confirmed with a DMSA scan showing absent uptake of the isotope on one side, with the contralateral kidney often showing compensatory hypertrophy.
-When URA is diagnosed, a voiding cystourethrogram should be performed, because there is a 30% incidence of contralateral reflux.
ANOMALIES OF ASCENT
Simple Renal Ectopia
When the mature kidney fails to reach its normal location in the “renal” fossa, the condition is known as renal ectopia. An ectopic kidney can be found in one of the following positions: pelvic, iliac, abdominal, thoracic, and contralateral.The ureter usually enters the bladder on the ipsilateral side with its orifice positioned normally. 50% percent of ectopic kidneys have hydronephrotic collecting system which result from obstruction at the ureteropelvic or the ureterovesical junction or from reflux grade III or greater, or from the malrotation alone. Most ectopic kidneys are clinically asymptomatic
Prognosis: The ectopic kidney is no more susceptible to disease than the normally positioned kidney, except for the development of hydronephrosis or urinary calculus formation
Horseshoe Kidney
Horseshoe kidney occurs in 0.25% of the population. Horseshoe kidney is found more commonly in males (2: 1). In 95% of cases, the kidneys join at the lower pole, rarely an isthmus connects both upper poles The migration is usually incomplete, with the kidneys lying lower in the abdomen than normal. It is presumed that the inferior mesenteric artery prevents full ascent by obstructing the movement of the isthmus. Generally, the isthmus is bulky and consists of parenchymatous tissue with its own blood supply. Occasionally it is composed of fibrous tissue.Treatment:
Patient usually asymptomatic and treatment directed toward complication as stone, infection.CYSTIC DISEASES OF THE KIDNEY
The kidney is one of the most common sites in the body for cyst formation. Cystic Diseases of the Kidney may be inheritable (Autosomal recessive (infantile) polycystic kidney disease, Autosomal dominant (adult) polycystic kidney disease) or Noninheritable (multicystic dysplastic kidney, Simple cysts).AUTOSOMAL RECESSIVE (INFANTILE) POLYCYSTIC KIDNEY DISEASE
ARPKD has been referred to as the “infantile” form in the past; however, the disease can present in adolescents and young adults, although less frequently. It is rare disease. Of those infants who survive the neonatal period, approximately 50% are alive at 10 years of age.
Genetics:
Mutations of a single gene located on chromosome (6).
Clinical Features:
Affected children typically present in utero with enlarged, echogenic kidneys. Oligohydramnios is common because of the lack of normal urine production by the fetus. The infant often displays Potter facies and deformities of the limbs and may have respiratory distress as a consequence of pulmonary hypoplasia. Thirty to 50 percent of the affected individuals die shortly after birth as a result of uremia or respiratory failure. Hypertension and renal insufficiency are the major manifestations in surviving children, with liver disease becoming more prevalent in older patients.
Treatment:
No cure has been found for ARPKD. Patients who survive may require treatment for hypertension, congestive heart failure, and renal and hepatic failure.
AUTOSOMAL DOMINANT (ADULT) POLYCYSTIC KIDNEY DISEASE
Incidence of approximately 1 in 1000 live births. Although most cases are identified between the fourth and fifth decades of life, the condition has been reported in newborns and infants.
A number of associated anomalies are common, including cysts of the liver, pancreas, spleen, and lungs; aneurysms of the circle of Willis (berry aneurysms); colonic diverticula; aortic aneurysms; and mitral valve prolapsed. Hepatic cysts are more prevalent and their size greater in females
Genetics: mutation in the genes PDK1 (chromosome 16 )and PDK2(chromosome 4).
Clinical Features:
Typically, signs or symptoms first occur between the ages of 30 and 50 years These include microscopic and gross hematuria, flank pain (pain caused by bleeding into the cysts, urinary tract infection ), gastrointestinal symptoms (perhaps secondary to renomegaly or associated colonic diverticula), renal colic (secondary either to clots or stones), and hypertension.
Evaluation:
-family history
-Abdominal ultrasonography may reveal renal cysts as well as cysts in other organs.
-CT or MRI: may be helpful in some cases and often is superior to ultrasonography for detecting cysts in organs other than the kidney.
Treatment:
There is no known cure at this time. Current therapy is directed toward lessening the complications of ADPKD and delaying the onset of ESRD.
-controlling the blood pressure, chronic pain treated by medication if not respond treated by open or laparoscopic deroofing. Infection, stone treated accordingly. Renal failure treated by hemodialysis or renal transplant.
MULTICYSTIC DYSPLASTIC KIDNEY
Multicystic dysplastic kidney is a developmental anomaly resulting in multiple cysts of varying sizes, without identifiable normal renal parenchyma.Etiology:
- Obstruction theory: multicystic kidney is an extreme form of
obstructive hydronephrosis that occurs secondary to atresia of the
ureter or renal pelvis.
-ureteric bud theory: MCDK may result from abnormal interaction between the ureteric bud and metanephric mesenchyme.
Clinical Features:
Multicystic dysplasia is the second most common cause of an abdominal mass in infants.
The contralateral kidney frequently is abnormal. For example, contralateral ureteropelvic junction obstruction is found in 10% of infants with MCDK, and contralateral vesicoureteral reflux is seen in 30% of infants
- Abdominal ultrasonography: the multicystic kidney has a haphazard distribution of cysts of various sizes without a larger central or medial cyst and without visible communications between the cysts.
-radioisotope studies: no uptake of isotope.
SIMPLE CYSTS
Simple renal cysts are the most common cystic lesions found in the human kidney. They are usually oval to round, may be solitary or multiple, unilateral or bilateral, and are filled with plasma-like clear fluid.
Clinical Features:
they are discovered incidentally on ultrasonography, CT, However, cysts can produce an abdominal mass or pain, hematuria secondary to rupture into the pelvicalyceal system, and hypertension secondary to segmental ischemia.
Evaluation:
To diagnose a benign simple cyst on ultrasonography, it should(1) Have no internal echoes,
(2) Have a sharply defined, thin, distinct smooth wall,
(3) Be spherical or oval with no internal echoes.t.
When these criteria are not met, CT with contrast enhancement must be performed.
Bosniak’s Classification of Simple and Complex Cysts
Category ISimple benign cyst with no echoes within the cyst, sharply, marginated smooth wall; requires no surgery
Category II
septation, minimal calcification, and high density; requires no surgery
Category II F
Although calcification in wall of cyst may even be thicker and more
nodular than in category II, the septa have minimal enhancement,
especially those with calcium; requires no surgery
Category III
More complicated lesion that cannot confidently be distinguished
from malignancy, having more calcification, more prominent
septation of a thicker wall than a category II lesion; more likely to
be benign than malignant; requires surgical exploration and/or
removal
Category IV
Clearly a malignant lesion with large cystic components, irregular margins; solid vascular elements; requires surgical removal.
MEGAURETERS
It means dilated ureter. A normal ureteral diameter is rarely greater than 5 mm, whereas ureters wider than 7 to 8 mm considered megaureters.
Two pathologic types:
(1) Refluxing megaureter caused by high grade vesicoureteral reflux( primary or secondary VUR)
(2) Obstructive megaureter from narrowing of the distal segmental of the ureter.
Evaluation
- Ultrasound is the initial study.- VCUG is subsequently obtained in most cases to rule out reflux.
- Diuretic nuclear renal scan.
Treatment: according to the cause of megaureter. Obstructive megaureter treated by excistion of obstructed segment and reimplantation of the ureter.