Pelviectasis: Definition and Treatment Approach
Pelviectasis is a dilation of the renal pelvis (part of the kidney's collecting system) that requires monitoring but often resolves spontaneously in most cases, particularly in children, and only requires intervention when causing obstruction, infection, or renal dysfunction.
Definition and Diagnosis
Pelviectasis refers to the dilation or enlargement of the renal pelvis, which is the central collecting area of the kidney where urine collects before flowing into the ureter. It is commonly detected during:
- Prenatal ultrasound (antenatal hydronephrosis)
- Abdominal imaging for other conditions
- Evaluation of urinary symptoms
The condition is diagnosed through imaging studies:
- Ultrasound (most common initial test)
- CT scan or MRI (for more detailed evaluation)
- Diethylenetriamine pentaacetic acid (DTPA) scan (to rule out obstruction)
Classification
Pelviectasis is typically classified based on the anterior-posterior (AP) diameter of the renal pelvis:
- Mild: 5-9 mm
- Moderate: 10-15 mm
- Severe: >15 mm
Natural History and Prognosis
Research shows that isolated antenatal hydronephrosis (pelviectasis) has a favorable prognosis:
- 25% resolve by the first postnatal ultrasound
- 82% show normal or only mild pelviectasis by 2 years of age 1
- Deterioration occurs in only about 5% of cases 1
Treatment Approach
1. Monitoring and Observation (First-line for most cases)
For mild to moderate pelviectasis without symptoms or complications:
- Regular ultrasound monitoring (every 3-6 months)
- Monitoring of renal function through blood tests
- No active intervention required
2. Antibiotic Prophylaxis
- Consider in cases with moderate to severe pelviectasis to prevent urinary tract infections
- Particularly important in children with vesicoureteral reflux
3. Interventional Treatment
Intervention is indicated when pelviectasis is associated with:
- Urinary tract obstruction
- Recurrent infections
- Deteriorating renal function
- Progressive dilation
Treatment options include:
Surgical Options:
- Pyeloplasty (for pelviureteric junction obstruction)
- Ureteral reimplantation (for vesicoureteral reflux)
- Endoscopic procedures (stent placement, balloon dilation)
Minimally Invasive Drainage:
- Internal ureteral stenting
- Percutaneous nephrostomy tube placement
4. Management of Pelviectasis in Special Populations
Prenatal/Neonatal Cases:
- Postnatal ultrasound evaluation (typically at 2-4 weeks of age)
- Using appropriate thresholds for different gestational ages (<6 mm before 20 weeks, <8 mm at 20-30 weeks, <10 mm after 30 weeks) can predict insignificant postnatal pelviectasis with high accuracy (sensitivity 89%, specificity 96%) 2
Pelviectasis Due to Malignancy:
- In cases of ureteral obstruction due to pelvic malignancies, internal stenting may fail in approximately 58% of cases, particularly in cervical cancer (92% failure rate) 3
- External drainage via percutaneous nephrostomy may be more appropriate in these cases
Complications and Prognosis
If left untreated when intervention is indicated, pelviectasis can lead to:
- Urinary tract infections
- Kidney damage
- Renal function impairment
- Pain and discomfort
However, with appropriate management:
- Most cases of isolated pelviectasis resolve or improve spontaneously
- Renal growth remains normal in the majority of cases 1
- Even in moderate to severe cases requiring surgery, the risk of irreversible renal damage is about 39% 4
Follow-up Recommendations
- For mild cases: Ultrasound every 6-12 months
- For moderate cases: Ultrasound every 3-6 months
- For severe cases: More frequent monitoring (every 1-3 months)
- Consider renal function tests and voiding cystourethrogram as needed
Key Takeaways
- Most cases of pelviectasis, especially those detected prenatally, resolve spontaneously
- Treatment should focus on preventing complications rather than treating the dilation itself
- Surgical intervention is reserved for cases with obstruction, infection, or renal dysfunction
- Regular monitoring is essential to detect progression or complications