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Protein in your urine, or proteinuria, is a sign that your kidneys are damaged and not working as well as they should
Protein in your urine, or proteinuria, is a sign that your kidneys are damaged and not working as well as they should.
When your kidneys are healthy, they filter waste from your blood but retain proteins and other nutrients your body needs. However, if your kidneys are not functioning properly, protein can leak into your urine.
Proteinuria is common among the elderly and people with chronic health conditions, affecting approximately 6.7% of the total population.
How does protein enter your urine?
Glomeruli are part of the filtration system of your kidneys which transport small molecules into the urine but not bigger proteins or blood. Ducts (narrow, hollow vessels in the kidneys) retrieve tiny proteins that pass through glomeruli and retain them in the body.
However, if the glomeruli or tubules are damaged, protein will flow into your urine instead of being reabsorbed by your blood
The amount of protein in your urine is measured by a urine test. Although a modest quantity of protein in your urine is acceptable, levels should not exceed 150 mg per day.
Although proteinuria may be an early symptom of kidney disease, your doctor may examine you again to rule out other factors such as dehydration. Three positive findings in three months or more indicate kidney disease.
7 causes of proteinuria
Proteinuria is a complicated condition, and causes vary from one person to another. Common causes may include:
- High blood pressure: People with high blood pressure may have weakened blood vessels in their kidneys. This can prevent the kidneys from properly filtering protein. Hypertension may not cause noticeable symptoms until it progresses to a more serious stage.
- Diabetes: In people with type I diabetes, the pancreas does not produce enough insulin, resulting in elevated blood sugar levels. In people with type II diabetes, the pancreas produces enough insulin, but the body is unable to use it effectively. High blood sugar can damage protein molecules in the inner lining of blood vessels in the kidneys, which can lead to kidney disease.
- Glomerulonephritis: Glomerulonephritis is an inflammatory condition of the glomeruli of the kidneys. Some types of glomerulonephritis are caused by autoimmune diseases such as lupus or rheumatoid arthritis, as well as infections such as hepatitis B and human immunodeficiency virus (HIV), which can lead to protein leaking into urine.
- Urinary tract infection: Infection in the kidneys can trigger widespread inflammation and cause filtration barrier disruption. This can cause transient proteinuria.
- Fever: High fever due to any cause may often result in transient proteinuria.
- Chemicals: Excessive use of protein powder, steroids, chemicals, herbs, or other alternative therapie can negatively impact kidney function.
- Medications: Medications such as painkillers (nonsteroidal anti-inflammatory drugs), gold (used in traditional medicine), nicotine, penicillamine, and lithium carbonate may cause proteinuria.
What are symptoms of protein in urine?
If you only have a small amount of protein in your urine, you may not experience symptoms. However, if your kidneys are severely damaged, you may experience:
- General body edema
- Foaming, fizzy, or effervescent urine
- Dehydration due to passing urine more often
- Low energy and fatigue
If you notice these symptoms, contact your doctor as soon as possible.
How is a proteinuria urine test done?
A urine test can help diagnose proteinuria. Clinicians use test strips to test a portion of the urine sample, and the tip changes color when there is too much of any chemical present in the urine. The urine sample is then inspected for residue.
To diagnose a disease, urine samples are inspected for compounds that shouldn't be there. These include red blood cells, white blood cells, bacteria, and crystals that can turn into kidney stones.
How is proteinuria treated?
Proteinuria is a symptom of an underlying disorder, so treatment involves addressing the cause.
If your proteinuria is minor and only lasts a few days, you may be able to manage the condition by such measures as limiting protein intake to 0.6 mg/kg body weight, drinking enough water, and reducing salt intake.
Treating chronic conditions before they progress to kidney failure is essential. If you have hyperglycemia and/or hypertension, your physician may prescribe medication such as:
- Angiotensin-converting enzyme (ACE) inhibitors: Help the veins and arteries to relax and thin, reducing blood pressure.
- Angiotensin receptor blockers (ARBs): Used to treat high blood pressure and cardiovascular disease and may be prescribed for chronic kidney disease.
