UreteroPelvic Junction Obstruction

DONE BY\ Eman Salman Al-

Hassan

King Faisal University

College of Medicine

- Definition- Etiology- Epidemiology- Clinical Presentation- Differential diagnosis- Investigations - Treatment- References

OBJECTIVES

Ureteropelvic junction (UPJ) obstruction is defined as a partial or complete obstruction of the flow of urine from the renal pelvis to the proximal ureter. It can be congenital or acquired with a congenital PUJ obstruction being one of the commonest causes of antenatal hydronephrosis.

DEFINITION

- Intrinsic obstruction may result from stenosis due to scarring of ureteral valves.

- Extrinsic obstruction by ureteral hypoplasia may result in abnormal peristaltic emptying of the renal pelvis into the ureter through the UPJ.

- Crossing lower-pole renal vessel(s) or entrapment of the ureter by a vessel can prohibit urinary flow down the ureter.

- Rotation of the kidney and renal hypermobility

- Iatrogenic obstruction caused by prior surgical intervention to treat other disorders or failed repair of a primary UPJ obstruction.

ETIOLOGY

EPIDEMIOLOGY

- By Ultrasound1\100 of pregnancies present with fetal upper urinary tract dilatation1\500 are diagnosed with significant urologic problems

- UPJ obstruction is present in 50% of patients diagnosed with antenatal hydronephrosis

- The male-to-female ratio of is 3-4:1

- The left kidney is more commonly affected than the right kidney

- UPJ obstruction is less common in adults

- UPJ obstruction is bilateral in 10% of cases

Neonates - Hydronephrosis

Adults - Back and flank pain correlates with periods of increased fluid intake ingestion of a food with

diuretic properties - Urinary tract infection (UTI)

- Pyelonephritis- Hypertension

- Abdominal mass

Older children - Urinary tract infection (UTI)

- Flank mass- Intermittent flank pain

secondary to a primary UPJ obstruction

- Hematuria if it is associated with infection

CLINICAL PRESENTATION

It includes other causes of hydronephrosis.

Imaging studies differentiate UPJ obstruction from the following conditions: - Vesicoureteral reflux (VUR) - Transient hydronephrosis - Functional hydronephrosis - Other urological anomalies including: Posterior urethral valves, congenital megaureter, ureterocele, and multicystic dysplastic kidney.

DIFFERENTIAL DIAGNOSIS

INVESTIGATIONS

- Complete blood cell count (CBC)

- Coagulation profile

- Electrolyte levels

- Renal function assessment - Blood urea nitrogen (BUN) and serum creatinine levels- Urine culture

LABORATORY TESTS

Often show a dilated renal pelvis with a collapsed proximal ureterwith doppler sonography the obstructed kidneys can show higher resistive indices.

ULTRASONOGRAPHY

It is performed to differentiate between obstructive vs nonobstructive hydronephrosis.

- PUJ "obstruction" will demonstrate excretion (downward slope on renogram) after administration of diuretic from the collecting system. - Mechanical obstructive hydronephrosis will demonstrate no downward slope on renogram, with retained tracer in collecting system.

DIURETIC RENOGRAPHY

May show evidence of hydronephrosis +/- calyectasis with collapsed ureters. Useful for assessing crossing vessels at the PUJ especially when surgical intervention is planned.

CT

- Dilatation of the renal pelvis and caliceal system with a stenotic ureteropelvic segment.- Delayed drainage of contrast media from the from the renal pelvis.- Intravenous urography is often not used in children, since better alternatives (e.g. MR urography) are available

FLUOROSCOPY - IVU

MRUIt is used in assessing UPJ obstruction. The study also provides details of renal vasculature, renal pelvis anatomy, location of crossing vessels, renal cortical scarring, and ureteral fetal folds in the proximal ureter.

TREATMENT

Currently, no available medical therapy is capable of reversing UPJ obstruction in either adults or children.

In children\ initially conservative treatment with monitoring. Intervention is indicated in the event of significantly impaired renal drainage or poor renal growth.

MEDICAL THERAPY

The accepted criteria for intervention in infants and children including: 1- clearance half-time (T 1/2) greater than 20 minutes2- Differential function less than 40%.3- Ongoing parenchymal thinning with or without contralateral compensatory hypertrophy. 4- Associated symptoms like: pain, hypertension, hematuria, secondary renal calculi, and recurrent urinary tract infections.

SUGRICAL THERAPY

- The obstructed segment is completely resected, with reanastomosis of the renal pelvis and ureter in a dependent funneled fashion. The success rate exceeds 95%.- Gold Standard- Anderson-Hynes dismembered pyeloplasty is the most common

OPEN PYELOPLASTY

- Incision of the area with a balloon catheter to help ensure a complete incision followed by prolonged ureteral stenting, for a period of 4-8 weeks. Success rates are 80-90%.- Anterograde or retrograde- Slightly less effective in children

ENDOPYELOTOMY

- Better in adults- They are useful when a long-strictured segment of diseased ureter is encountered. - The proximal ureter is re-created with redundant renal pelvis that is tubularized.

SPIRAL-VERTICAL FLAP

- Laparoscopic pyeloplasty offers a minimally invasive- Used in patients with either primary or secondary UPJ obstruction- Offers the advantages of decreased morbidity, shorter hospital stay, and quicker recovery.

LAPAROSCOPIC PYELOPLASTY

- Prophylactic antibiotic therapy should be given postoperatively. - Remove the endopyelotomy stent after 4-8 weeks.- Follow up with renal ultrasonography 1-3 months after surgery. - Follow up with IVP or nuclear medicine renal scan 3-6 months after surgery.- Serial renal imaging is recommended for the first year after surgery.

FOLLOW UP

http://radiopaedia.org/articles/pelviureteric-junction-obstruction

http://emedicine.medscape.com/article/450785-overview

https://www.harrisonmedical.org/home/ureteropelvic-junction-obstruction-2

http://urology.ucla.edu/body.cfm?id=478&ref=7&action=detail

REFERENCES

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