The Kidney Clinic

Things to Know About Proteinuria

Doctor sharing about Proteinuria.

Things to Know About Proteinuria

Proteinuria is a medical condition characterised by excessive amounts of protein in the urine, causing bubbles to form during urination. It is not a disease but a symptom of an underlying medical condition. Proteinuria can also be a sign of kidney damage. Therefore, it is crucial to identify the underlying cause to prevent further kidney damage.

Does Proteinuria Cause Symptoms?

Proteinuria may not cause any noticeable symptoms in some individuals but in other individuals, causes a wide variety of symptoms, depending on the underlying cause and the seriousness of the condition.

Foamy or frothy urine: One of the most common symptoms of proteinuria is the appearance of foamy or bubbly urine. Foamy urine occurs when excess protein is present in the urine, which causes urine to be thick and frothy.

Swelling in the feet, legs, or ankles: Proteinuria can cause the body to retain fluid, which leads to swelling in the feet, ankles, or legs. This swelling, known as oedema, may be more noticeable in the morning or after prolonged periods of standing or sitting.

Fatigue: Excessive protein loss in the urine can also cause fatigue, tiredness, and lack of energy.

Loss of appetite: In some cases, proteinuria may cause nausea, vomiting or loss of appetite. Loss of appetite may occur due to the underlying condition that is causing the proteinuria or as a result of the body’s response to the protein loss.

Weight gain: Proteinuria can cause fluid retention, leading to weight gain. This weight gain may be due to an increase in body fat or an increase in fluid volume.

Hypertension: High blood pressure, or hypertension, can be a symptom of proteinuria. The kidneys play a significant role in regulating blood pressure. When they are not functioning correctly due to proteinuria, it can lead to high blood pressure.

If left untreated, proteinuria can lead to more severe complications, such as kidney failure.

Types of Proteinuria

Different types of proteinuria can be classified based on the amount and type of protein present in the urine.

► Microalbuminuria: Only small amounts of albumin, a specific type of protein, are present in the urine. Microalbuminuria is often an early sign of kidney damage in people with diabetes and hypertension.

► Selective proteinuria: The leakage of specific proteins, such as albumin or immunoglobulins, which may indicate certain autoimmune diseases or kidney disorders.

► Non-selective proteinuria: Various types of proteins, including albumin and immunoglobulins, are present in the urine. Non-selective proteinuria is a common sign of kidney disease and can occur in multiple medical conditions.

► Orthostatic proteinuria: The protein content of urine rises when they stand but falls when they lay down. It is generally considered a benign condition and is more common in children and adolescents.

► Overflow proteinuria: The kidneys are unable to process a specific type of protein, such as immunoglobulins or light chains, leading to their accumulation in the urine. Overflow proteinuria is a common sign of certain medical conditions, such as multiple myeloma or amyloidosis.

Proteinuria Diagnosis

Diagnosing proteinuria typically involves a combination of physical exams, laboratory tests, and imaging studies. Here is a general overview of what the process might look like:

► Physical exam: A healthcare provider will conduct a physical exam and review the patient’s medical history. They may ask about any symptoms the person is experiencing, such as swelling in the hands and feet or changes in urine colour or odour.

► Urine test: A simple urine test, known as a urinalysis, is usually the first step in diagnosing proteinuria. This test measures the levels of protein in the urine. It can provide important information about the type and severity of the condition. If the urinalysis shows elevated protein levels, additional tests may be necessary to determine the underlying cause.

► Blood test: Besides a urinalysis, a healthcare provider may order a blood test to measure the person’s kidney function and check for signs of other underlying conditions, such as diabetes or autoimmune diseases.

► Imaging studies: In some cases, imaging studies such as an ultrasound or CT scan may be ordered to examine the kidneys and urinary tract closely. These tests can help identify any abnormalities or blockages contributing to proteinuria.

► Kidney biopsy: A kidney biopsy may also be recommended to help diagnose proteinuria.

Causes of Proteinuria

Here are some common kidney conditions and other factors that can cause proteinuria:

► Kidney diseases: Conditions like glomerulonephritis, diabetic nephropathy, and polycystic kidney disease can affect the kidneys’ ability to filter properly, leading to protein leakage into the urine.

► Diabetes: If you have diabetes, high levels of sugar in your blood can damage the blood vessels and nerves in your kidneys, causing kidney damage and proteinuria.

► High blood pressure: When your blood pressure is consistently high, it can damage the blood vessels and in your kidneys and cause proteinuria.

► Infections: Some infections like urinary tract infections and kidney infections can cause proteinuria.

► Autoimmune diseases: Conditions such as lupus and Goodpasture syndrome, which are autoimmune disorders, can damage the kidneys and cause proteinuria.

Medications: Some medications, including nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, and chemotherapy drugs, have been associated with proteinuria as a side effect.

Other conditions: There are other situations that can cause proteinurias, such as heart failure, multiple myeloma (a type of blood cancer), and preeclampsia during pregnancy.

Treatment Options for Proteinuria

Treatment options for proteinuria depend on the severity and cause/aetiology of the condition. When proteinuria is brought about by conditions like diabetes or high blood pressure, the primary objective is to manage and address the underlying medical condition. This often involves making lifestyle changes such as adopting a healthy diet, engaging in regular physical activity, and maintaining a healthy weight. In certain cases, medications like angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) may be prescribed to regulate blood pressure and reduce proteinuria.

As for the other causes of proteinuria, the treatment options may include immunosuppressive medications, supportive treatment to reduce the symptoms and treatment to prevent any side effects from the immunosuppressive medications. In general, people with proteinuria develop swelling. We will advise a low salt diet, fluid restrictions and oral medications to help remove the excessive fluid.

For more severe cases of proteinuria and kidney damage, a nephrologist may suggest dialysis to filter waste products and excess fluids from the blood. Once the underlying cause of proteinuria has been identified, the nephrologist can recommend an appropriate treatment plan to help manage the condition and prevent further kidney damage.

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