Congenital anomalies of renal tract

Bifid collecting system :   - Most frequent. - Unilateral or bilateral. - Incomplete ; sometimes only pelvis is bifid , 10 %o f population, (not significant) - Complete ; (1-2 % of population), two ureters may be separate down to their insertion into the bladder.

Upper moiety ureter inserts inferior and medial to its normal site , or ectopically to vagina or urethra leading to urine incontinence if beyond urethral sphincter, may associate with obstruction or uretrocele. - Lower moiety ureter inserts into normal anatomical position, usually associated with reflux.

Renal agenesis : - Incidental finding.   - Incidental finding. The opposite kidney shows compensatory hypertrophy . - Can be diagnosed as absent kidney on ultrasound or CT. - IVU will show a single kidney with active contrast excretion .

Ectopic kidney:   - Result from halted ascend of kidneys during fetal development . - Often are incidental findings during routine ultrasound , usually located in the lower abdomen and rotated, short ureter. - Chronic pyelonephritis, calculi and hydronephrosis are more common in ectopic kid. .

Horse shoe kidney -Kidneys may fail to separate.   -Almost invariably the lower poles remain fused. -The kidneys axes are more parallel to the spine and malrotated. -Diagnosis can be made by plain x-ray in some cases. -US, CT scan and MRI can better demonstrate the anatomy and morphology hence the diagnosis. -May be an incidental finding. -PUJ obstruction and calculi formation are common . IVU shows 1. The kidneys at low position . 2.Close to the spine with long axis parallel to the spine . 3. Malrotation manifested by medially directed calyces. 4- The renal pelvis and ureters are anterior and lateral in position .

Poly cystic disease Adult type Present after the third decade of life , Familial. Renal parenchyma is replaced by numerous cysts containing fluid , The cysts are of variable size , Clinically renal colic, loin mass , heamaturia and hypertension, Renal tissue interposed between the cysts after time dssimcted ended with renal failure Almost bilateral.

IVU Large kidney . Lobulated out-line. Distortion of pelvi- calyceal system depend on cyst size, number and position. In advanced cases there is elongation and stretching of minor and major calyces ( spider leg). In advanced cases IVU shows non-functioning kidney .

Infantile type : Usually affect liver, spleen and pancreas , Incompatible with life . I.V.U. Bilateral Large kidney due to numerous small cysts (1-2 mm size ). - The out-line is not lobulated as in adult. - I.V.U, may be normal. - Nephrogram shows minute filling defects.

Infantile hydronephrosis ( PUJ OBSTRUCTION ): IVU shows : Marked dilatation of pelvis and may be extra-renal. Calyceal dilatation is late and in advanced cases form foot shape PCS The ureter is not seen and when it is seen looks normal . Delayed film with I.V. diuretic produce gross dilatation .

Congenital anomalies of ureter Mega ureter : - Unilateral or bilateral dilatation of the ureter with no evidence of organic obstruction. Cause – unknown Retrocaval ureter : The middle third of right ureter curve medially behind the IVC , then laterally to regain it’s normal position , this lead to obstruction of upper third of ureter.

Ureterocele : Congenital cystic dilatation of lower end of ureter ( intra-mural part) due to pin-hole meatus . May be simple or ectopic . simple : the orifice is in proper position of bladder , Ectopic >> in bladder neck , urethra , uterus & vagina . IVU : - There is rounded or elliptical dilatation of lower end of ureter with thin linear filling defect around it , resembling (cobra head appearance), - Proximal dilatation of rest of ureter . - In advanced cases hydronephrosis . - In obstructed ureterocele , filling defect in the bladder

(bladder extrophy) : Ectopia vesica  bladder located at low position & plain x-ray shows separation of symphysis pubis .