Symptoms

• Hydronephrosis because of an acute obstruction can cause intense pain in the flank or loin. Unilateral hydronephrosis might not cause any pain.
  
  

Cause

• Obstructions within the urinary tract that might cause hydronephrosis include blood clots and kidney stones. Obstructions outside the urinary tract include abdominal or pelvic tumors.
  
  

Tests

• A blood test can show an elevated creatine level and the urine might also have a raised pH. An ultrasound or computed tomography (CT) scan are common imaging studies for hydronephrosis.
  
  

Treatment

• The treatment of hydronephrosis usually involves the removal of the causative obstruction. Upper urinary tract obstructions are usually treated by inserting a nephrostomy tube. Lower urinary tract obstructions are usually treated with a urinary catheter.
  
  

Prognosis

• Hydronephrosis of one kidney might not require surgery. But hydronephrosis of both kidneys has a poor prognosis if left untreated.