Treatment of Right Hydronephrosis
The treatment of right hydronephrosis depends critically on the presence of infection, renal function impairment, and severity of obstruction—with urgent decompression via percutaneous nephrostomy (PCN) or retrograde ureteral stenting required for infected hydronephrosis (pyonephrosis), sepsis, acute kidney injury, or intractable pain, followed by definitive treatment of the underlying cause. 1, 2, 3
Immediate Risk Stratification and Urgent Intervention
Emergency decompression is lifesaving and takes priority over all other considerations in the following scenarios:
Infected hydronephrosis (pyonephrosis) with sepsis: PCN or retrograde ureteral stenting with antibiotics is first-line treatment, as antibiotics alone are insufficient 1. PCN achieves 92% patient survival compared to 60% with medical therapy alone and provides superior bacteriological information 1.
Acute kidney injury: Bilateral hydronephrosis or severe unilateral obstruction causing elevated creatinine requires urgent decompression 2, 3.
Intractable pain: Severe flank pain unresponsive to medical management warrants urgent drainage 1, 3.
Choice of Decompression Method
PCN is preferred when patients are unstable, have multiple comorbidities, high anesthesia risk, or when larger tube drainage is needed for pyonephrosis 1. Technical success rates exceed 90% 1.
Retrograde ureteral stenting is an alternative but may carry higher risk of urosepsis in extrinsic ureteral obstruction 1. It is better tolerated long-term than external PCN tubes 1.
Preprocedural antibiotics are mandatory when infection is suspected, with third-generation cephalosporins (ceftazidime) showing superiority over fluoroquinolones 1.
Diagnostic Workup to Determine Etiology
Once stabilized (or if no urgent indications exist), systematic evaluation identifies the cause:
Initial Imaging
Ultrasound of kidneys and bladder is the first-line imaging study to confirm hydronephrosis and assess severity 2, 3. Severity classification uses anteroposterior renal pelvis diameter (APRPD >15 mm = severe) or Society for Fetal Urology grading (grade 3-4 = severe) 2, 3.
Urinalysis and renal function tests assess for infection, hematuria, and kidney injury 2, 3.
Advanced Imaging for Cause Determination
CT urography (CTU) with IV contrast is the preferred comprehensive study, providing 100% sensitivity for stones and detecting masses, strictures, or extrinsic compression 2. It evaluates the entire genitourinary tract morphologically and functionally 1, 2.
CT abdomen/pelvis without contrast detects stones and guides stone management 2.
MR urography (MRU) is the alternative when IV contrast is contraindicated (renal insufficiency, contrast allergy) or in atypical anatomy 2, 3.
MAG3 renal scan with diuretic is the gold standard for confirming functional obstruction versus non-obstructive dilation and assessing differential renal function 2, 3. T1/2 >20 minutes indicates obstruction 2, 3.
Special Considerations with Hematuria
If hydronephrosis presents with hematuria, malignancy evaluation is mandatory 2:
High-risk patients (age >35-40 years, smoking history, occupational chemical exposure, gross hematuria history, prior urologic malignancy, pelvic irradiation, chronic UTIs) require cystoscopy in addition to upper tract imaging 2.
CTU remains the preferred imaging for comprehensive evaluation 2.
Etiology-Specific Definitive Management
Obstructing Urolithiasis
Stones with infection require urgent decompression before definitive stone treatment 2.
Retrograde ureteral stenting prior to ureteroscopic stone extraction is preferred for definitive management 1. Extracorporeal shock-wave lithotripsy with stenting shows higher complete stone eradication rates than PCN alone 1.
Stones without infection can be managed based on size and location per CT findings 2.
Ureteropelvic Junction Obstruction (UPJO)
Surgical intervention (pyeloplasty) is indicated when 2, 3:
- T1/2 on diuretic renography >20 minutes
- Differential renal function <40%
- Declining function >5% on serial scans
- Progressive dilation on imaging
Malignant Obstruction
PCN has higher technical success than retrograde stenting for pelvic malignancy causing extrinsic compression or ureteropelvic junction obstruction 1.
PCN followed by delayed surgery allows decompression prior to definitive surgical therapy when the patient becomes an appropriate candidate 1.
Posterior Urethral Valves (Males)
Immediate urology referral is required 3.
Voiding cystourethrography (VCUG) should be performed in males with moderate-to-severe hydronephrosis to exclude this diagnosis 3.
Vesicoureteral Reflux
Accounts for approximately 30% of urinary tract abnormalities with hydronephrosis 3.
Higher grades of hydronephrosis correlate with increased VUR severity 3.
Medical Management Without Decompression
This approach is only appropriate when 1:
- No evidence of obstruction on imaging
- No infection or sepsis
- Normal or stable renal function
- Manageable pain
Medical management consists of IV fluids, antibiotics (if infection present), and close clinical and imaging follow-up 1.
Follow-Up Strategy
For Persistent Hydronephrosis After Initial Treatment
Ultrasound monitoring at minimum every 2 years to assess for progression 2, 3.
Serial MAG3 scans if differential function declines >5% to guide intervention timing 2, 3.
Prophylactic antibiotics to prevent UTI in severe cases 3.
Conversion from PCN to Internalized Stent
- Percutaneous antegrade ureteral stenting is typically delayed 1-2 weeks following initial PCN placement 1. Double-J ureteral stents are better tolerated long-term than external PCN tubes 1.
Common Pitfalls to Avoid
Never treat infected hydronephrosis with antibiotics alone—decompression is mandatory and lifesaving 1.
Do not delay imaging workup in patients with hematuria and hydronephrosis, as malignancy must be excluded 2.
Avoid relying solely on ultrasound for stone detection—sensitivity is only 32-57% depending on kidney side 1. CT is required for definitive stone evaluation 2.
Do not assume non-obstructive dilation without functional confirmation—MAG3 diuretic renography is required to differentiate true obstruction from dilation 2, 3.
Monitor for postprocedural bacteremia and sepsis when draining infected systems, even with preprocedural antibiotics 1.