Postnatal evaluation of hydronephrosis

At birth :

• Clinical examination to observe urinary stream (poor in PU valves), renal masses, distended bladder which is firm in PU valves, abdominal wall muscles, undescended testes (Prune belly syndrome). [In suspected PU valves - immediate catheterisation is required to drain the urinary bladder and relieve back pressure
  
  [In suspected PU valves - immediate catheterisation is required to drain the urinary bladder and relieve back pressure.]
 
• USG, MCU, serum creatine / BUN (to be repeated after 6 weeks of relief of obstruction to evaluate effect of obstruction on renal function).

Antenatal USG evaluation of HDN can detect the above mentioned causes, which need confirmation postnatally by clinical evaluation, micturating cystourethrography (MCU), radionucleide Tc99DTPA or MAG renal scan.

Approach to Unilateral hydronephrosis

• If a unilateral hydronephrosis is detected, USG should be repeated after 3-7 days when dilatation becomes more evident.
 
• If ureter is dilated - MCU should be done to detect VUR.
 
• If ureter is not seen- Tc99DTPA renal scan with diuretic renography should be done to detect PUJ obstruction and its severity so that surgery is planned.

Approach to Bilateral mild to moderate HDN

Same as above + S. creatine / BUN to diagnose renal insufficiency.

Aims of systematic evaluation of hydronephrosis is to detect obstructive lesions which may require surgery in asymptomatic stage to prevent progressive renal damage for e.g.

• Recurrent UTI leading to reflux nephropathy and CRF;
 
• Obstructive nephropathy leading to CRF / ESRD, hypertension, growth failure, anemia and urolithiasis.

Indications of surgery in HDN

• PUJ obstruction
 
• At initial diagnosis -
  
  
  • Symptomatic HDN (UTI, renal mass, growth failure),
    
    
  • Solitary kidney with impaired function,
    
    
  • Bilateral severe HDN
    
 
• Relative renal function of obstructive kidney <30%.
 
• ON FOLLOW UP-
  
  
  • 10% decline in relative renal function on DTPA renal scan when repeated after 6-12 weeks
    
    
  • Increasing HDN
    
    
  • Post urethral valves, ureteroceles
    
    
  • VUR Grade IV-V persisting beyond infancy
    
    
  • New renal scars or recurrent UTI despite antibiotic prophylaxis
    
    

Management of Hydronephrosis:

• In asymptomatic HDN or HDN which is mild to moderate and stable after USG within 3-7 days, with no obstruction (Hydronephrosis due to? VUR)
  
  
  • Antibiotic prophylaxis (amoxycillin /cephalexin for 3 months and then oral cotrimoxazole / nitrofurantoin single night dose for 6 months - 2 years to prevent UTI.
    
    
  • Urine cultures may be necessary if fever occurs.
    
    
  • Diuretic renography, MCU are recommended at 1-2 months after antibiotics
    
    
  • USG after a year.
    
 
• If VUR is detected,
  
  
  • DMSA renal scan to detect renal scars
    
    
  • Surgery may needed if scars are present or there is presence of Grade IV-V VUR.
    
    
  • Repeat MCU/diuretic venography at 2 years to decide about resolution of VUR.
    
    
  • DMSA renal scan should be done every 2-3 yearly if scars are persistent or to detect presence of new scars.
    
    
  • BP; growth monitoring; S. Creatine / BUN, USG should be done yearly till 15-20 years.
    

Acquired hydronephrosis :

Hydronephrosis can occur due to acquired causes like

• Urolithiasis or stone disease,
 
• Stricture of ureter due to tuberculosis or following urologic surgery.

The underlying cause should be treated, obstruction removed by ESWL or surgery. Kidney can be permanently damaged because of pus formation in an obstructed hydronephrotic kidney due to pyonephrosis.

Last created on 04-06-2001
Last updated on 01-07-2006