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Persistent Proteinuria:
What Is Persistent Proteinuria?
Persistent proteinuria is the term doctors use when you constantly have high levels of protein in your urine. Protein is a part of your blood, and is important for building muscles and bones, regulating fluid in your blood, fighting infection, and tissue repair.
When it shows up in your urine, at levels above normal, it can be a sign of an issue. Persistent proteinuria could be a sign your kidneys are damaged.
Connection to Berger's Disease
Persistent proteinuria is common when you have Berger's disease, also called immunoglobulin A (IgA) nephropathy. IgA nephropathy is an autoimmune disease that causes buildup of IgA antibodies in your kidneys.
These IgA clumps damage the tiny vessels that filter your blood. As a result, your kidneys leak blood and protein into your urine.
Who Gets Persistent Proteinuria?
Anyone can get persistent proteinuria, but some populations are more likely to get it, including people who:
- Are 65 or older
- Have a family member who has or had kidney disease
- Are Black, Hispanic, Native American or Pacific Islander
People who have certain medical conditions are also at high risk of getting proteinuria. You're more likely to get it if you have:
- Dehydration
- Inflammation
- High blood pressure
- Kidney stones
- Immune disorders such as lupus or Goodpasture syndrome
- Diabetes
- Glomerulonephritis (inflammation in the kidneys)
- Intravascular hemolysis (destruction of red blood cells)
- Cardiovascular disease
- Preeclampsia (high blood pressure plus proteinuria in pregnancy)
- Kidney cancer
- Chronic kidney disease, such as IgA nephropathy
- Trauma
- Poisoning
- Congestive heart failure
How It Happens
Your kidneys are responsible for filtering wastes and extra water out of your blood. The first step for doing this uses tiny blood vessel units called glomeruli. Your blood enters the glomeruli for filtration and they catch the larger molecules like protein and blood cells so they don't go into your pee.
When these glomeruli are damaged - like they are from the buildup of IgA deposits in Berger's disease, they can't catch these proteins and blood cells like they typically do. Other problems can lead to proteinuria, too, such as problems with tubules (long, thin tubes in your kidneys that filter at a later stage), and problems with protein reabsorption.
Symptoms
When you have proteinuria, you may not have any symptoms at first. With persistent proteinuria and kidney damage, the most common symptoms are symptoms of chronic kidney disease, and include:
- Swelling (edema) in your face, belly, feet or ankles.
- Needing to pee urgently
- Shortness of breath
- Tiredness
- Nausea and vomiting
- Decreased or no appetite
- Muscle cramps at night
- Puffiness around your eyes, especially in the morning
- Foamy or bubbly urine
Your doctor needs to know if you're having these symptoms, because they're signs of kidney problems.
Persistent Proteinuria Diagnosis
Diagnosing protein in your pee is simple and easy - your doctor just uses a dipstick test. To take the test, you pee into a cup and a technician dips a paper strip into the pee. If the strip turns a certain color, it tells your doctor protein is present. The presence of protein in your urine will mean more tests may be necessary, especially if you have signs of kidney issues.
Your doctor will also do a urinalysis test. During this test, a clinician looks at your pee under a microscope to see what substances are there. They look at the color and check for abnormal parts like white blood cells, red blood cells, protein, and bacteria.
Importance of Diagnosis
You need a diagnosis of persistent proteinuria as a first step toward identifying and treating the underlying cause. Constant protein in your pee can be a sign of kidney damage or even failure, and you may have other complications.
Your risk of death from heart disease and cardiovascular disease goes up when you have persistent proteinuria. If proteinuria is a sign of chronic kidney disease, you may slowly lose kidney function and need dialysis or a kidney transplant.
When to See a Doctor
If you're having any of the symptoms of persistent proteinuria, especially swelling or foamy pee, see your doctor right away.
How Doctors Diagnose Persistent Proteinuria
After the dipstick and urinalysis tests show protein in your pee, especially if your doctor repeats the tests over 3 months, your doctor will want to do other tests to check your kidney health. These include:
- Creatinine clearance test. Creatinine is a waste product that your kidneys take out of your blood and add to your pee. If your kidneys aren't working, this process doesn't work right. Your doctor measures how much creatinine is in your blood and pee to see if your kidneys are clearing it correctly.
- Glomerular filtration rate (GFR) blood test. This test shows your doctor how well your kidneys are filtering waste. They take a sample of your blood and look at the levels of creatinine and albumin (a protein) in it. They compare this information to typical levels for your age, size, assigned sex at birth, and race. This tells your doctor how well your kidneys are working.
- Blood test. Your doctor may look at your blood to measure levels of protein in the serum.
- Imaging tests. Tests like CT scans and ultrasounds can help your doctor look more closely at your kidneys to see if something is blocking filtration, like a stone or tumor.
- Kidney biopsy. This test requires a doctor to remove a small piece of your kidney tissue. They'll send the sample to a lab where a technician will look at it under a microscope to see how damaged it is and try to find the cause.
Signs Persistent Proteinuria is Getting Worse
Doctors don't use symptoms alone as a way to mark whether persistent proteinuria is getting worse, because by the time symptoms are bad, kidney damage is happening.
To monitor your persistent proteinuria when you have IgA nephropathy, your doctor can use a tool called the MEST-C score. This score puts you into one of three categories based on measures of specific lab results.
Your doctor gets this score by looking at lab results of a kidney biopsy. They look for numbers of certain cells in your glomeruli, scarring, and other measures of injury to your kidney cells.
- Grade I is a score of 0-1, with a 1-year renal survival rate of 94.1%
- Grade II is a score of 2-4, with a 10-year renal survival rate of 86.9%
- Grade III is a score of 5-7, with a 10-year renal survival rate of 74.1%
This score helps your doctor decide your prognosis, risk for end stage renal disease, and complications like dialysis.
Persistent Proteinuria Treatment
The treatment you need to manage your persistent proteinuria depends on the cause. If you have kidney disease, you may need medication, diet changes, and exercise. Diabetes that's causing proteinuria needs tighter blood sugar control. Preeclampsia, which happens during pregnancy, is serious and needs careful monitoring. It typically goes away after the baby is born.
Treating IgA Nephropathy
If you have IgA nephropathy, there are medications that can help with proteinuria, including:
- High blood pressure drugs. These drugs include angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs). As they lower blood pressure, they can reduce how much protein your body is losing.
- Sodium-glucose cotransporter-2 (SGLT2) inhibitors. These medications help you lower blood sugar levels and your blood pressure, which lowers the amount of work the kidneys have to do. They can help slow the progression of kidney disease. Your doctor may prescribe these alongside ACE inhibitors or ARBs.
- Steroids. These drugs, typically corticosteroids, calm your immune system and keep it from overreacting. They can come with many side effects, so your doctor will keep a close eye on your reaction to them. They have been shown to reduce proteinuria.
- Omega-3 fatty acids. Your doctor can prescribe these supplements to help curb inflammation.
- Cholesterol medicine. If you have high cholesterol, medication to lower it may help slow kidney damage.
- Diuretics. These medications help your body get rid of excess fluid that causes swelling in your hands and feet.
- Endothelin receptor [type A] antagonists (ERAs). These medications relax the blood vessels in your kidneys, which can lower the amount of protein in your pee and slow down kidney damage.
- Hydroxychloroquine. Doctors typically prescribe this drug to treat malaria. Recent studies have shown it can help improve kidney function in people with IgA nephropathy proteinuria.
Post-treatment outlook
Having persistent proteinuria may shorten your life expectancy, but if you get a proper diagnosis and treatment for the underlying cause, your outlook is good. Many of the conditions that cause it are treatable.
Preventing Progression of Persistent Proteinuria
You can't prevent proteinuria, but you can manage the underlying causes and make lifestyle changes to help reduce risk and slow damage. These include:
- Eat less protein, so there's less in your bloodstream.
- Eat less salt to help lower your blood pressure.
- Eat more fiber to reduce your cholesterol and keep your blood sugar steady
- Exercise at least 2 hours a week, ideally spread out during the week.
- Keep close tabs on your blood sugar.
- If you smoke or use tobacco, stop.
- Avoid nonsteroidal anti-inflammatory drugs (NSAIDs).
Is there a vaccine?
So far, there aren't any available vaccines, but you can manage the symptoms of it through treatment and lifestyle changes.
How other conditions affect persistent proteinuria
Certain medical conditions can cause problems when you have persistent proteinuria:
- Diabetes. If you have type 2 diabetes, your nephrons (filtration units) in your kidneys slowly get thicker and scar over time. This prevents them from working how they should, and they leak protein into your pee. This can happen years before you have any symptoms of kidney disease.
- High blood pressure. When you have high blood pressure, it makes your blood vessels weaker. Since your kidney blood vessels are doing the filtering, they can't keep protein out as well.
Learn More About Persistent Proteinuria
What to Know about Urine Tests
Proteinuria (Protein in Urine)
High Blood Pressure and Kidney Disease