Hydronephrosis is a condition that puts pressure on the kidneys and can lead to damage. Often, something inside or outside of the urinary tract blocks the urine flow out of the kidneys and causes ... A: Hydronephrosis treatment constitutes a physical examination initially, followed by a diagnosis of the underlying cause of the disease. As soon as your doctor detects the cause, he or she can then term it as mild, moderate, or severe Hydronephrosis. Hydronephrosis is a common abnormality of the kidney found on various imaging studies. This occurs when urine builds up in the kidney and causes it to swell. Hydronephrosis can result from a blockage of the urine outflow from the kidney or from reflux of urine into the kidney. What is hydronephrosis? The term hydronephrosis refers to a dilated kidney collecting system. The collecting system of the kidney is where the urine is collected in the kidney before it drains into the ureter and then ... Hydronephrosis is when your kidneys swell because your body can't release all of its pee. It can affect one or both kidneys and may be caused by blockages, reflux, or birth defects. Learn more about the diagnosis and treatment options.