Hydronephrosis: Developing Innovative Therapies

April 2021

Hydronephrosis is a disease that affects the kidneys and urinary bladder. This disorder occurs when there is a blockage of urine flow as it travels through the ureters, which are narrow tubes connecting the kidneys to the bladder. Hydronephrosis can be life-threatening if it's not treated quickly.

If you're interested in developing innovative therapies for this disorder, read on for more information about what causes hydronephrosis, its symptoms, potential treatments and more...

What causes hydronephrosis?

In a healthy person, the process of urination works like this: Urine is made in the kidneys. Urine flows from the kidneys through a tube called the ureters into the bladder. When the bladder has reached its full size, urine flows out of it into a hollow organ called the bladder neck. The ureters then connect to another hollow organ in which urine moves out through small tubes called ducts. Here, urine is picked up by small tubes (the renal tubules) that carry it through longer channels to where it leaves your body in the urethra. If there is a blockage in any part of this pathway, urine cannot get out of the body. This is called urinary retention or "bladder wall" obstruction (note: hydronephrosis is not a type of urinary retention)

Clues to the cause of hydronephrosis

In some cases of bladder wall obstruction, the exact cause may not be known. However, the following clues may help to narrow down causes.

  • Surgical history and surgery scars
  • If a person has had surgery for an injury or cancer, one possibility is that an abscess developed in the ureter or bladder wall during this time. This is known as an operable obstruction.

  • Symptoms of an infection

  • Bladder wall does not usually have a layer of tough cells that stops bacteria from harming it, so passing urine into the bladder wall can cause pain and irritation. This can be confused with urologic symptoms of an infection.

  • Previous urinary tract infections in infancy (UTI)

  • In some cases, damage to the bladder wall may be caused by a simple urinary tract infection in infancy, when the body's immune system produces antibodies that attack healthy cells. This may lead to scarring and inflammation.

    Symptoms of hydronephrosis

    Bladder wall obstruction can be asymptomatic, but most people experience some or all of the following symptoms:

  • Painful urination (dysuria): This is sometimes described as a feeling of "need to pass urine but can't". Sometimes there is no pain, and the person with this disorder may not realise that they have a problem. 

  • Increased frequency of urination (polyuria): This can be embarrassing, especially if the person does not know that they have a problem.

  • Occasional blood in the urine (hematuria): or noticeable blood in their urine that creates a "rusty" or "coffee-ground" appearance when examined with a microscope under light microscopy (haematuria).

  • Frequent need to pass urine, may have urgency, or burning sensation/pain when trying to pass urine which may lead to straining to pass urine.
  • Hydronephrosis: Innovative Therapies

    A patient’s weight should not limit him or her when seeking treatment for hydronephrosis (a condition that occurs when urine builds up in the renal pelvis or ureters). In recent years, doctors have become more creative with treatments that are safer than previous methods like surgery. Percutaneous embolization, or PE for short, is a way to treat the problem. The surgery begins with a catheter that is inserted in the ureter to deliver material (such as a polymer, or clot-forming substance) that helps stop the urine from building up in the body. This prevents infection within the body.

    Minimally invasive surgery

    In some patients who have hydronephrosis, it becomes necessary to open up the bladder and kidneys in order to improve function and prevent damage to other organs. However, having open surgery can be difficult because of pain and difficulty breathing. There are minimally invasive treatments that have been introduced in recent years, such as laparoscopic ureterolysis. This procedure is done through an abdominal incision rather than open surgery and removes painful kidney stones that build up in the ureters. The catheter is inserted into the ureter and releases material that dissolves the stones and prevents them from growing again. This is a simpler, safer alternative to open surgery, which can be risky for patients who have poor kidney function as well as those who are obese or overweight.

    With innovative medical therapies like percutaneous embolization, many patients can be helped with their condition without invasive treatment.

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