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Proteinuria is the medical term used to describe the presence of protein in the urine. This symptom may indicate potential damage to your kidneys and requires early and thorough methodical exploration. In this article, we will explore the possible causes, symptoms, diagnosis, and available treatment for proteinuria.
◉ Having protein in urine
Proteinuria is a condition characterized by the presence of an abnormally high amount of protein in urine, resulting from particular physiological or pathological situations.
Temporarily high levels of protein in urine are not unusual. However, consistently high levels can be a sign of kidney disease.
Detection of proteinuria can be done using a variety of methods, such as urine dipsticks, lab tests to measure total protein, or specifically albumin
A thorough medical evaluation is needed to determine the underlying cause. Regular medical monitoring and appropriate treatment are essential to manage proteinuria and prevent long-term complications.
Measurement of protein in urine by urine dipstick
◉ Physiology of proteinuria
The presence of protein in the urine can be due to several physiological and pathological processes:
- The glomerulus in the kidneys, serves as the primary filtration site, filters the blood and retains large proteins, such as serum albumin.
- Proteins with a molecular weight below a certain threshold freely cross the glomerular basement membrane and are reabsorbed in the renal tubule.
There are three main mechanisms for increased urinary protein excretion.
- Increased glomerular permeability due to certain glomerular diseases, such as glomerulonephritis, autoimmune diseases, can lead to significant proteinuria.
- Tubular disorders, such as Fanconi syndrome, can interfere with normal protein reabsorption. This can lead to the loss of various proteins in the urine.
- In certain pathological conditions, there may be an overproduction of certain low molecular weight proteins that exceed the filtration capacity of the kidneys.
◉ Normal level of protein in urine
The normal level of protein in urine in a random sample is typically less than 150 milligrams per day (mg/day) or less than 10 milligrams per deciliter (mg/dL) when measured in a 24-hour urine collection.
In neonates, it may be normal up to 300 mg/day..
Within these limits, proteinuria is considered physiological, consisting of Tamm-Horsfall mucoproteins, low molecular weight proteins and a very low amount of albumin.
◉ Causes and types of protein in urine
There are several types of proteinuria, each associated with different causes and conditions. Here are some of the more common types:
◉ Transient proteinuria
It is the temporary presence of protein in the urine, it is by far the most common form of proteinuria and usually disappears without treatment. Here are some causes:
- Fever
- Intense exercise
- Infections.
- Being in very cold temperatures
- Seizures
- Dehydration
- High stress
◉ Orthostatic proteinuria
In orthostatic proteinuria, protein can be detected in the urine when an individual is standing but not when lying down. This type of proteinuria is commonly seen in children and young adults and usually goes away with age.
◉ Persistent glomerular proteinuria
Glomerular proteinuria is usually due to increased permeability of the glomerular barrier in the kidneys. This increase in glomerular permeability can be caused by various conditions, such as
- Idiopathic nephrotic syndrome
- Focal segmental glomerulosclerosis.
- Congenital nephrotic syndrome (Finnish, mesangial sclerosis).
- IgA nephropathy.
- Membranous nephropathy.
- Membranoproliferative GN.
- Alport Syndrome. Other thin membrane nephropathies.
- Acute post-infectious GN
- Systemic diseases (SLE, PSH)
- Diabetes
- Amyloidosis
- Infections: HBV, HCV, HIV
◉ Persistent Tubular Proteinuria
- Isolated, family or sporadic
- Tooth disease (hypercalciuria, nephrocalcinosis)
- Fanconi syndrome, cystinosis, Lowe syndrome, Wilson disease
- Mitochondrial diseases
- Polycystic kidney disease
- Toxic: heavy metals, Chinese herbs, aminoglycosides
- Tubulointerstitial nephritis
- Acute tubular necrosis
- Secondary to obstructive uropathy
◉ Possible symptoms
Protein in urine may not always cause noticeable symptoms on its own. In many cases, it is detected through routine urine tests or during medical evaluations. However, as the condition gradually worsens, you may eventually experience symptoms such as:
- Frothy or bubbly urine.
- Swelling (oedema) in the hands, feet, stomach and face.
- Wee more often.
- Shortness of breath.
- Tired.
- Loss of appetite.
- Stomach pain and vomiting.
- Muscle cramps at night.
If you notice symptoms of proteinuria, tell your doctor as soon as possible.
◉ How is proteinuria diagnosed?
The presence and measurement of proteins in the urine, can be carried out using various diagnostic methods. Here are a few:
◉ Detection of proteinuria by urine dipstick
Dipsticks are a commonly used tool to detect the presence of protein in a urine sample. They offer a semi-quantitative assessment, i.e. a rough estimate of the amount of protein present.
- Wash your hands thoroughly and then your genital area with soap and water.
- Start urinating into the toilet, then stop and place the sterile collection container under your urine stream.
- Collect at least 30 milliliters of urine in the container, then finish urinating in the toilet.
- Remove a strip from its wrapper.
- Soak the strip in the urine sample for the recommended time (usually a few seconds).
- Remove the test strip from the urine and tap it gently to remove excess urine.
- Wait recommended time (usually 1 minute) for test results to develop.
Results are usually interpreted based on color changes on the strip, comparing the reaction with a reference scale.
Urine protein dipstick test
◉ 24 hour proteinuria test
The 24-hour proteinuria test is a laboratory test that accurately quantifies the amount of protein in urine over a 24-hour period.
Several techniques are used for the determination of proteinuria over 24 hours: colorimetric reaction, immunoassay, nephelemetry, turbidimetry, etc.
◉ Other tests
- Urine protein electrophoresis
- Albumin/creatinine ratio:
- Creatinine Clearance Test
- Glomerular filtration rate
- Examination of the urinary sediment
- Renal biopsy puncture
◉ Treatment
It is important to emphasize that the treatment of proteinuria is individualized according to the underlying cause (diabetes, hypertension, preeclampsia, etc.) and the specific needs of each patient. It is essential to work closely with your doctor to determine the appropriate treatment plan and ensure adequate follow-up.
Taking your medications as prescribed by your healthcare professional is crucial to taking care of yourself. It is important to follow the prescribed dosage and frequency of your medications to ensure they are effective in managing your condition
If you have proteinuria that is mild or temporary, you may not need treatment.
Here are some tips that can help you:
- Have a balanced diet
- Stay hydrated: Drinking enough water helps maintain kidney function and can help flush toxins from your body.
- Managing salt intake: Limiting your salt (sodium) intake can help lower blood pressure and reduce the strain on your kidneys.
- Manage stress
- Increase fiber intake: A diet high in fiber can help regulate blood sugar, promote healthy digestion and lower cholesterol levels.
- Regular physical activity
- Blood Glucose Monitoring: Good blood sugar control can help reduce the risk of complications, including kidney damage.
- Quitting smoking: Smoking can damage blood vessels and worsen kidney function.
- Limit alcohol consumption: Excessive alcohol consumption can be harmful to the kidneys.
- NSAIDs, such as ibuprofen and aspirin, can harm the kidneys when used excessively or for prolonged periods.
Note :It is always best to consult your doctor for personalized advice and recommendations based on your individual health condition.