Kidney & Urinary Tract

Hydronephrosis

Swelling of the kidney caused by a build-up of urine when drainage is blocked or slowed.

Overview

Hydronephrosis is a finding on ultrasound or other imaging, not a disease itself. Causes include stones, strictures, prostate enlargement, pregnancy, or congenital narrowing at the kidney outlet (PUJ obstruction).

Common symptoms

  • Often none — found on a scan
  • Flank or side pain
  • Urinary infection
  • Reduced urine output in severe cases

When to see a urologist

Hydronephrosis with pain, fever or a single functioning kidney needs urgent review. Mild, symptom-free swelling still needs a cause to be identified.

This website provides general educational information and is not a substitute for an individual medical consultation. Diagnosis and treatment should be based on assessment by a qualified healthcare professional.