Nephrotic Syndrome: Causes, Symptoms & Treatment

Introduction

Nephrotic syndrome is a medical condition that occurs when the kidney filters are damaged. These filters usually take back the protein in your blood and prevent it from going into the urine. When they are damaged, excess protein leaks into the urine. This can cause your body to lose important proteins that help maintain fluid balance in your blood vessels. As a result of this imbalance, some of the fluid starts to leak out into your tissues, leading to swelling, which is called oedema. You might notice swelling in your legs, ankles, or around your eyes. Your urine may also look foamy due to the extra protein in it.¹

Let us discuss the causes, symptoms, and treatments available for nephrotic syndrome.

Signs and Symptoms of Nephrotic Syndrome

The following are the signs and symptoms of pneumonia, to look out for:

• Excretion of high amounts of the protein albumin in the urine (albuminuria)
• Elevated levels of fat and cholesterol in the blood (hyperlipidemia)
• Swelling (oedema) usually in the feet, ankles, or legs that can also occur in the hands or face
• Reduced levels of albumin in the blood (hypoalbuminemia)
• Appetite loss
• Not feeling well
• Pain in the abdomen (from the ribs to the pelvis)
• Production of foamy urine²

Most children with nephrotic syndrome have times when their symptoms are under control (remission), followed by times when symptoms return (relapses). In most cases, relapses become less frequent as they get older and often stop by their late teens.

Dr. Ashish Bajaj – M.B.B.S, M.D.

When to See a Doctor

If you or anyone known to you starts to show symptoms of nephrotic syndrome such as swelling in the face, belly, or limbs, or skin sores, it is essential to consult your healthcare provider immediately. Similarly, in case you are undergoing treatment for nephrotic syndrome but the symptoms persist or do not improve, it is crucial to let your doctor know. In case of new symptoms such as decreased urine output, cough, fever, severe headache, or discomfort while urinating, it is also important to seek medical attention. Prompt consultation with a healthcare provider is recommended to avoid any potential complications and to manage the condition effectively.³

Nephrotic syndrome causes your kidneys to release too much protein in your urine. Causes include kidney diseases that affect the tiny filters inside your kidneys. Symptoms include swelling, high amounts of protein in your urine and low amounts of protein in your blood.

Dr. M.G. Kartheeka, MBBS, MD

Causes of Nephrotic Syndrome

Nephrotic syndrome can be caused by:

• Nephrotic syndrome is typically caused by damage to the glomeruli, which are tiny blood vessels in the kidneys that filter the blood.
• Glomerular damage can result from various diseases and conditions, such as diabetic kidney disease, minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, systemic lupus erythematosus, and amyloidosis.
• Nephrotic syndrome can also be caused by secondary factors, including infections such as HIV/AIDS, hepatitis B and C, certain medications such as non-steroidal anti-inflammatory drugs, some allergic reactions, genetic disorders that affect the kidneys, and other underlying medical conditions.
• The primary causes of nephrotic syndrome are focal segmental glomerulosclerosis (FSGS), membranous nephropathy, and minimal change disease.
• FSGS is the most common cause of nephrotic syndrome in Black adults, while membranous nephropathy is the most common cause in white adults, and minimal change disease is the main cause in children.^4,5

Risk Factors for Nephrotic Syndrome

Nephrotic syndrome is a condition caused by damage to the filtering system of the kidneys,  that filter the blood and remove excess fluids. Several factors can increase the risk of developing nephrotic syndrome, including:

• Medical conditions that damage the kidneys, such as diabetes, lupus, amyloidosis, reflux nephropathy, and other kidney diseases.
• Taking certain medications, including nonsteroidal anti-inflammatory drugs and drugs used to fight infections.
• Infections such as HIV, hepatitis B, hepatitis C, and malaria can be a contributing factor that may increase the risk of nephrotic syndrome.
• Although anyone can get nephrotic syndrome, it is slightly more common in men than in women. In children, it often occurs between the ages of two and six. It is important to consult a doctor if you suspect symptoms of nephrotic syndrome or have any risk factors for the condition.^5,6

Diagnosis of Nephrotic Syndrome

Here are the tests or procedures done by your healthcare provider for the diagnosis of nephrotic syndrome:

• Urine test: Urinalysis can be used to detect protein abnormalities in urine samples, and a 24-hour urine collection may be needed.
• Blood test: Blood tests can indicate low levels of albumin, high cholesterol and triglyceride levels in the blood, as well as measure creatinine and urea nitrogen levels to evaluate overall kidney function.
• Kidney biopsy: A small sample of kidney tissue may be removed for laboratory testing through a needle inserted through the skin into the kidney.⁷

Treatment of Nephrotic Syndrome

Treatment for nephrotic syndrome involves managing symptoms and treating underlying causes, which may include the following:

Reduction of symptoms using medications such as:

• To minimise protein loss and regulate blood pressure, angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) are used.
• Diuretics (pills that help in water removal) to reduce swelling by helping the kidneys remove excess fluid from the body.
• Statins to lower cholesterol levels, although their effectiveness in improving outcomes for people with nephrotic syndrome is not clear.
• Blood thinners, such as heparin, warfarin, dabigatran, apixaban, and rivaroxaban, may be used to decrease blood clotting.

Management of underlying cause:

• Medications that suppress the immune system, such as corticosteroids, rituximab, cyclosporine, and cyclophosphamide, may be prescribed if the underlying cause is related to an autoimmune disease.
• Treating underlying conditions that may be causing nephrotic syndrome, such as diabetes, lupus, or amyloidosis.
• In some cases, a kidney biopsy may be needed to determine the underlying cause and appropriate treatment.

It’s important to note that treatment for nephrotic syndrome is individualized based on each person’s unique situation and may involve a combination of the above treatments. Close monitoring by a healthcare professional is also necessary to manage symptoms and prevent complications.^4,7

Prevention of Nephrotic Syndrome

Prevention:

• There is no sure way to prevent nephrotic syndrome but managing underlying conditions such as diabetes and high blood pressure can reduce the risk.
• Regular check-ups with a healthcare provider can help detect any early signs of kidney problems before they worsen and lead to nephrotic syndrome.

Management:

• Work with a registered dietitian to develop a diet plan that meets your individual needs and helps manage your symptoms.
• Reduce protein intake as recommended by a dietician, since excess protein can put additional strain on the damaged kidneys.
• Limit sodium intake to help prevent swelling and control blood pressure. Avoid processed and packaged foods high in sodium.
• Choose low-fat and low-cholesterol foods to prevent high cholesterol levels, which can worsen nephrotic syndrome. Opt for lean cuts of meat and fish, and avoid fried or fatty foods.
• Stay hydrated by drinking plenty of water to help flush out toxins and reduce the risk of kidney damage.
• Follow any medication and treatment plans prescribed by your healthcare provider to manage underlying conditions and prevent further kidney damage.^2,6

Complications of Nephrotic Syndrome

Complications of nephrotic syndrome can include:

• High risk of infections due to loss of antibodies and other proteins that help fight infection.
• Blood clots due to the loss of blood proteins that prevent clotting, which increases the risk of developing a blood clot in veins.
• High blood pressure or hypertension due to the damage caused to glomeruli and the buildup of excess body fluid.
• Elevated blood cholesterol and triglycerides levels due to the liver releasing more cholesterol and triglycerides when albumin levels fall.
• Poor nutrition caused by the loss of too much blood protein, resulting in malnutrition, anaemia, and low blood protein and vitamin D levels.
• Acute kidney injury due to the inability of the kidneys to filter blood properly, resulting in waste products building up quickly in the blood. This may require emergency dialysis.
• Chronic kidney disease, which may occur due to the loss of kidney function over time. Dialysis or a kidney transplant may be necessary eventually.
• Increased risk of infections due to the compromised immune system.^4,5

Research Facts About Nephrotic Syndrome

Here are some facts about nephrotic syndrome you probably didn’t know:

• Focal Segmental Glomerulosclerosis (FSGS) is more likely to cause Nephrotic Syndrome in adults than in children, and it is most commonly found in individuals aged 45 years or older.
• In children, the primary cause of Nephrotic Syndrome is Minimal Change Disease, which is responsible for about 80% of cases.⁸

Frequently Asked Questions (FAQs)

References:

1. Nephrotic syndrome [Internet]. National Kidney Foundation. 2022. Available from: https://www.kidney.org/atoz/content/nephrotic  
2. Nephrotic syndrome: Causes, symptoms & treatment [Internet]. Cleveland Clinic. Available from: https://my.clevelandclinic.org/health/articles/5989-nephrotic-syndrome  
3. Nephrotic syndrome [Internet]. Mount Sinai Health System. Available from: https://www.mountsinai.org/health-library/diseases-conditions/nephrotic-syndrome 
4. Nephrotic syndrome in adults – NIDDK [Internet]. National Institute of Diabetes and Digestive and Kidney Diseases. U.S. Department of Health and Human Services; [cited 2023Apr25]. Available from: https://www.niddk.nih.gov/health-information/kidney-disease/nephrotic-syndrome-adults#causes
5. Nephrotic syndrome [Internet]. Mayo Clinic. Mayo Foundation for Medical Education and Research; 2022 [cited 2023Apr25]. Available from: https://www.mayoclinic.org/diseases-conditions/nephrotic-syndrome/symptoms-causes/syc-20375608 
6. Nephrotic syndrome treatments, causes & symptoms [Internet]. American Kidney Fund. 2023 [cited 2023Apr25]. Available from: https://www.kidneyfund.org/all-about-kidneys/other-kidney-problems/nephrotic-syndrome-treatments-causes-symptoms#who-is-at-risk-for-nephrotic-syndrome 
7. Nephrotic syndrome [Internet]. Mayo Clinic. Mayo Foundation for Medical Education and Research; 2022 [cited 2023Apr25]. Available from: https://www.mayoclinic.org/diseases-conditions/nephrotic-syndrome/diagnosis-treatment/drc-20375613 
8. Home – nephcure kidney international [Internet].  Available from: https://nephcure.org/wp-content/uploads/2021/04/Nephrotic-Syndrome-Fact-Sheet-4.12.18.pdf 

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