What is chronic pyelonephritis?
Chronic pyelonephritis describes the long-term damage recurrent urine infections cause to the kidneys. It is a diagnosis doctors often make when they are not sure exactly what has caused scarring on the kidney’s surface and, ultimately, kidney failure.
What causes chronic pyelonephritis?
The cause of chronic pyelonephritis is unclear, partly because the condition may develop with no evidence of infection.
It can be caused by reflux nephropathy. This happens when the kidneys are damaged by urine flowing backwards from the bladder to the kidney because of a leaky valve between the bladder and the ureter.
Whatever the cause, its effects vary widely. It may cause few problems, sometimes only affecting one kidney, but sometimes causing end-stage renal disease, which is treated with dialysis and/or a transplant. Occasionally the removal of one kidney (nephrectomy) is necessary. Blood pressure (BP) is often raised.
Reflux nephropathy
Urine flows from the kidneys, through the ureters and into the bladder. Each ureter has a one-way valve that allows urine to enter the bladder and prevents it from flowing back up the ureter. Reflux nephropathy, often just called reflux, occurs when these valves fail, allowing urine to flow backwards and into the kidney. If the bladder is infected or the urine contains bacteria, the kidney then becomes infected (pyelonephritis).
Because the pressure in the bladder is generally higher than in the kidney, reflux exposes the kidney to unusually high pressure. Over time, this increased pressure will damage the kidney and cause scarring.
Reflux is often found when a child is checked for repeated or suspicious bladder infections. If the child is found to have reflux nephropathy, any siblings should also be checked because reflux can run in families. Also, an adult patient's children should be checked. This is especially true of female children.
What are the signs and symptoms of chronic pyelonephritis?
If symptoms occur, they might be symptoms of infection itself, such as a burning sensation when passing urine, or of chronic kidney disease (CKD) that has resulted from infections recurring over time, such as ankle swelling, tiredness and itching.
Other symptoms include:
- pain in your side, back or abdomen
- needing to urinate at night
- repeated urinary tract infections (UTIs) in early childhood
- a single urinary tract infection in a male.
Note: sometimes the disorder may not cause symptoms. It is picked up by routine blood tests, or when a patient is investigated for high blood pressure.
How is chronic pyelonephritis diagnosed?
Levels of a substance in the blood called creatinine may be raised if CKD has developed. Urine tests may show infection and low to moderate levels of protein in the urine. Other tests include:
- ultrasound scan
- specialist X-ray called an intravenous pyelogram (IVP)
- nuclear medicine scan
- computed tomography (CT) scan
- micturating cystourethrogram (MCU - this is not usually necessary).
How is chronic pyelonephritis treated?
Cases of uncomplicated chronic pyelonephritis may require no treatment. But many people will need some form of treatment and ongoing management, including:
- antibiotics
- medication for high blood pressure or cholesterol
- regular blood tests, urine tests and blood pressure monitoring
Even though there is no specific treatment for most people with chronic pyelonephritis, keeping the blood pressure within normal range (<130/80mmHg) may slow the progression of CKD. Rarely, people with reflux require surgery to place the ureter(s) back into the bladder to stop the reflux of urine.
What is the outlook for someone with chronic pyelonephritis?
The prognosis for people with chronic pyelonephritis is very variable. Many people have few problems other than occasional kidney infections. Others require monitoring by a kidney specialist. Some people will, however, go on to develop end-stage kidney failure and require long-term dialysis or a kidney transplant.