What is Reflux Nephropathy (chronic pyelonephritis)?
Reflux nephropathy (RN), a condition that damages the kidneys, typically starts showing symptoms in early adulthood with various signs of chronic kidney disease. These signs can include scarring in the kidney, shrinkage of tiny kidney structures called tubules, and loss of overall kidney tissue. In many cases, it’s caught during a routine check-up or during pregnancy.
In the past, this condition was known as chronic pyelonephritis because it was thought to come from repeated urinary tract infections (UTIs) during childhood. Around 1% to 3% of children have this condition and it can lead to a severe form of kidney disease called end-stage renal disease (ESRD) in 7% to 17% of those children worldwide. In fact, RN may be responsible for up to 10% of ESRD in adults.
Reflux nephropathy can occur in children in two ways – it can be acquired or be present from birth (congenital). The acquired form of RN is more common in girls and is usually diagnosed after a high-fever urinary tract infection. The congenital form of RN, however, is normally diagnosed before birth or during a follow-up for a condition called hydronephrosis, which is a swelling in the kidneys. No prior UTI is usually seen in these cases and this form is more common in boys.
What Causes Reflux Nephropathy (chronic pyelonephritis)?
Vesicoureteral reflux (VUR) is a condition where urine flows backward from the bladder into one or both of the tubes that carry urine from the kidneys to the bladder (ureters). This usually happens if the valves that normally prevent this backward flow don’t work properly or are located in the wrong spot.
As a result of VUR or some other birth defects related to the urinary tract, a patient could develop reflux nephropathy, which is a kidney condition that occurs due to long-term high pressure of urine that doesn’t contain any bacteria. This often leads to recurring urinary tract infections (UTIs), especially during early childhood.
But it’s crucial to note that not all patients with UTIs and VUR will develop reflux nephropathy. Hence, having these conditions doesn’t necessarily mean you will develop kidney problems.
Risk Factors and Frequency for Reflux Nephropathy (chronic pyelonephritis)
Reflux nephropathy (RN) is a health condition primarily affecting children or young adults, with a higher occurrence in females as compared to males. The exact number of cases and how widespread this condition is, however, are unknown. Around 20% of infants with a parent having a family history of Vesicoureteral reflux (VUR) also show this disorder, which is much higher than the 1% to 2% rate seen in the general population.
- About 10% to 30% of children and young adults with RN have high blood pressure.
- RN is thought to cause 12% to 21% of all cases of long-term kidney failure in children.
- It is the second most common cause of chronic disease affecting the tissue between the kidneys.
- According to a 2008 study, 3.5% of the 6491 children on dialysis had RN.
- It is the fourth leading cause of end-stage renal disease (ESRD) in children after focal segmental glomerulosclerosis (FSGS), renal aplasia, hypoplasia or dysplasia, and obstructive uropathy.
- It is responsible for 7% to 17% of ESRD in children around the world.
The worldwide adult population incidence of ESRD due to RN is unknown. In Europe, approximately 12% of patients requiring treatment for ESRD may have RN. In a study involving 127 adults (average age of 41 years) who were diagnosed with VUR during their childhood, significant results were found.
- 35% had scarring on one kidney.
- 24% had scarring on both kidneys.
- 24% had albuminuria (a condition where a protein called albumin is present in urine).
- 11% had high blood pressure.
- Of the patients with scarring on both kidneys, 83% had a reduced rate of blood filtration by the kidneys.
In countries like Turkey, RN accounts for 18.5% of the causes of chronic kidney disease (CKD). In pregnant women with VUR, around 40% of their children will also have this condition, and it is highly recommended to get the children tested.
Signs and Symptoms of Reflux Nephropathy (chronic pyelonephritis)
Refux Nephropathy (RN) is a condition that often shows no symptoms and is usually discovered during regular medical check-ups or in pregnancy tests. The symptoms in adults can differ based on whether the RN was present from birth or acquired later. Men with RN often experience high blood pressure, protein in urine, and declining kidney function. On the other hand, women tend to have recurring urinary tract infections (UTIs) but usually have a positive outlook.
There are certain risk factors for RN that include:
- The severity of Vesicoureteral Reflux (VUR)
- Recurring UTIs
- Bladder-bowel issues
- Younger age
- Delay in UTI treatment
How RN presents itself can vary based on the patient’s age. Characteristics may include:
- Recurring UTIs during childhood
- Extended bedwetting
- Severe urinary infections, such as kidney infections in infants and children
- Previous surgery to reattach the ureters to the bladder
- High blood pressure observed at presentation
- Abnormal kidney function, with high creatinine levels and low eGFR
- Variable kidney function
- Mild to moderate protein in urine
- High protein in urine may indicate secondary FSGS, confirmed by kidney biopsy
- Urinary stones
- A UTI with no noticeable symptoms during pregnancy
In pregnant women, UTIs, high blood pressure, and preeclampsia are common. About 20% of pregnant women with RN develop UTIs, and about 6% are at risk of severe kidney infections. For those with RN who seem healthy but have high blood pressure, small kidneys with thin outer layers may indicate the condition, which can be confirmed using a renal ultrasound. UTIs tend to be more common in adults who’ve had surgery to correct VUR.
Testing for Reflux Nephropathy (chronic pyelonephritis)
If your doctor suspects issues with your child’s kidneys, they will usually start by conducting a thorough examination while discussing any potential symptoms with you. They might also carry out a few preliminary lab tests to gather more information. These tests may include a basic or comprehensive metabolic panel, urine tests, complete blood count, and a urine protein to creatinine ratio test.
Regarding imaging, a kidney ultrasound is the most commonly used initial check for kidney related problems, such as hydronephrosis (kidney swelling due to a build-up of urine) and urinary tract infection (UTI). The ultrasound can be beneficial, but it’s not perfect – it might not pick up all cases of kidney inflammation and can’t specifically diagnose some conditions like vesicoureteral reflux (VUR), a condition where urine flows back into the kidneys from the bladder.
If the ultrasound shows hydronephrosis and the child has relevant symptoms, a diagnostic test called a voiding cystourethrogram (VCU) can be used. The VCU is primarily used to diagnose VUR.
For patients who have undergone surgery for VUR and need follow-ups, nuclear cystography can be used. This type of imaging test can help detect the condition but doesn’t provide detailed insights to grade VUR or spot other anatomical defects. It’s mainly used because it reduces exposure to radiation.
Another very sensitive test is a DMSA scan. This test uses a chemical called dimercaptosuccinic acid and is considered the gold standard for diagnosing acute kidney inflammation and kidney scarring.
Magnetic resonance imaging (MRI) can also be used to diagnose kidney scarring. This imaging test can distinguish between swelling and scarring, which a DMSA scan can’t. However, MRIs are not often used for infants and children due to factors such as cost and practicality.
If necessary, a kidney biopsy may also be done. A biopsy involves taking a small sample of kidney tissue for examination, which can help both in diagnosing the condition and predicting its likely course.
Treatment Options for Reflux Nephropathy (chronic pyelonephritis)
Low-grade Vesicoureteral Reflux (VUR), a condition where urine flows backwards from the bladder to the kidneys, often gets better on its own over time. However, it’s important to keep the urine free from bacteria while the condition resolves. People, especially children, with symptoms of VUR usually need long-term treatment using antimicrobials, immediate treatment for urinary tract infections (UTIs), or sometimes, surgery.
Preventive (prophylactic) antibiotics may be given depending on how often UTIs occur, the child’s age, and the severity of VUR. Medications used could include some well-known antibiotics. Also, managing bladder and bowel irregularities is crucial, which could involve the use of laxatives, stool softeners, scheduled bathroom breaks every 2 to 3 hours, exercises for the pelvic floor muscles, changes in behavior, and use of medications to relax the muscles in the bladder if needed.
In prolonged or severe cases of VUR, surgical treatment to reposition the tubes (ureters) that carry urine from the kidneys to the bladder may be considered. This is mostly beneficial for patients who have not responded to medical management, particularly preventive antibiotics, to avoid UTIs. Surgery might not be relevant for teenagers and adults who have permanent kidney damage or advanced signs of chronic kidney disease. The reasons to consider surgery may include repeated infections despite adhering to a routine of preventive antibiotics, worsening kidney damage, or non-compliance with antibiotics routine.
In patients with established RN (reflux nephropathy), a long-term kidney condition caused by VUR, it is important to prevent and aggressively manage high blood pressure. Appropriate medications to block the renin-angiotensin system, which regulates blood pressure and fluid balance, may be used in patients with abnormally high filtration of blood through the kidneys and those with noticeable protein in the urine.
For patients who develop end-stage renal disease (ESRD), different types of renal replacement therapies, which substitute normal kidney function, might be necessary. Despite a higher occurrence of UTIs, there’s no significant difference in complications after transplantation or survival rates among RN patients compared to the control group.
What else can Reflux Nephropathy (chronic pyelonephritis) be?
In simpler terms, chronic pyelonephritis, a long-term bacterial infection in one or both of the kidneys, is typically diagnosed by specific characteristics in the kidney. Reflux nephropathy (RN), a condition that occurs due to urine flowing back into kidneys, is identified by its polar scars. On the other hand, obstructive pyelonephritis, an infection caused by the blockage of urine flow, generally presents with general enlargement of the kidneys and a wasting away of the junction between the kidney’s outer layer and its inner structure.
When severe, Vesicoureteral reflux (VUR), a condition that allows urine to flow back into your ureters from your bladder, might resemble on x-ray images the appearance of polycystic kidney disease (multiple cysts or fluid-filled sacs within the kidney) or unilateral renal cystic disease (a condition that affects one kidney and can look like polycystic kidney disease).
What to expect with Reflux Nephropathy (chronic pyelonephritis)
If someone has a condition called Vesicoureteral Reflux (VUR) and is elder, their chances of getting better on their own are lower. This is also true if the VUR affects both sides of the body. The more severe and high-grade the VUR, the less likely it will resolve itself spontaneously.
Moreover, there’s another condition called proteinuria, which means having excessive protein in the urine. This condition can indicate a more serious disease called Chronic Kidney Disease (CKD). Its presence is often a signal that the CKD is likely to worsen in people with Reflux Nephropathy (RN), a kidney condition that’s often associated with VUR.
Possible Complications When Diagnosed with Reflux Nephropathy (chronic pyelonephritis)
The consequences of Reflux Nephropathy (RN) are well known but are often poorly defined because they develop subtly and progress slowly.
Here are some associated problems:
- Early slowed growth due to frequent bladder and kidney infections in children suffering from Vesicoureteral reflux (backflow of urine from the bladder into the kidneys) and later because of RN. This can cause complications for the mother as well.
- An abrupt increase in blood pressure along with associated kidney issues during pregnancy
- Fetal health risks in women with urine reflux and kidney scarring
Moreover, people with RN can develop high blood pressure, protein in urine, inability of the kidneys to concentrate urine, high potassium levels in the blood, a type of acidosis (too much acid in the body fluids), and chronic kidney disease. This kidney disease can get worse over time and can cause kidney failure. The chronic kidney disease that develops from RN can also lead to higher rates of heart disease and related issues.
Preventing Reflux Nephropathy (chronic pyelonephritis)
Patients and caregivers need to understand the crucial role of regular check-ups in monitoring any advancements in the patient’s condition. They should also be strongly urged to regularly take prescribed medications. These medicines are meant to protect against urinary tract infections (UTIs) and manage high blood pressure (HTN), so it’s essential to stick to the treatment plan.
Patients with a history of vesicoureteral reflux (VUR) – a condition that allows urine to flow back into the kidneys from the bladder – should be aware that their children might also be at risk of having this condition.
