Nephrotic Syndrome: Types, Causes, Symptoms and Treatment

Nephrotic syndrome is a complex kidney disorder that affects individuals of all ages, characterised by significant protein loss through the urine. This condition can lead to a range of clinical manifestations and can have profound implications on overall health and quality of life. Early diagnosis and effective management are crucial for those affected by nephrotic syndrome. In this article, we will explore the key aspects of nephrotic syndrome, providing you with the knowledge necessary for its effective management and treatment.

What is Nephrotic Syndrome?

Nephrotic syndrome is a clinical syndrome defined by the following key features:

• Massive proteinuria (typically exceeding 3 grams of protein per 24 hours)
• Hypoalbuminemia (low blood albumin levels)
• Hyperlipidemia (high blood lipid levels)
• Oedema (swelling)

Nephrotic syndrome occurs when damage to the kidney’s glomeruli increases membrane permeability, leading to excessive protein loss in urine. It may result from primary kidney diseases or secondary conditions like diabetes, lupus, infections, or certain medications. Next, we’ll discuss the types of nephrotic syndrome.

Types of Nephrotic Syndrome

Nephrotic syndrome is classified into three types: primary, secondary, and congenital or genetic.

• Primary Nephrotic Syndrome: Originates from kidney-specific diseases like minimal change disease (MCD) in children or focal segmental glomerulosclerosis (FSGS) in adults. These conditions directly affect the glomeruli, leading to significant protein loss in the urine. Other causes include membranous nephropathy and IgA nephropathy.
• Secondary Nephrotic Syndrome: Results from systemic diseases such as lupus or IgA vasculitis, infections like hepatitis B, HIV, or malaria, and certain medications, including NSAIDs and cancer therapies. It occurs when external factors indirectly damage the kidneys.
• Congenital/Genetic Nephrotic Syndrome: Present at birth, often due to genetic mutations or prenatal infections, causing severe early-onset symptoms.Diagnosed at birth, it often arises from genetic mutations (e.g., nephrin gene) or prenatal infections like syphilis or toxoplasmosis. This type leads to severe early-onset symptoms requiring immediate medical attention.

Nephrotic Syndrome Symptoms

The symptoms of nephrotic syndrome can vary from person to person, but some common signs include:

• Swelling (oedema) in various parts of the body, such as puffy eyelids, legs, ankles, feet, and lower abdomen, due to fluid retention
• Foamy urine, which occurs because of the presence of large amounts of protein in the urine
• Weight gain as a result of fluid retention
• Tiredness and a general feeling of fatigue
• Loss of appetite or reduced desire to eat
• High blood pressure (hypertension), which can be both a symptom and a complication of nephrotic syndrome

Nephrotic Syndrome Causes

Nephrotic syndrome arises from primary or secondary causes:

Primary Causes:

Directly affect the kidneys, including:

• Focal Segmental Glomerulosclerosis (FSGS): Scarring of glomeruli, common in Black adults.
• Membranous Nephropathy: Protein buildup in the kidney, prevalent in white adults.
• Minimal Change Disease: Leading cause in children, also seen in adults.

Secondary Causes:

Linked to other conditions such as:

• Glomerulonephritis: Kidney inflammation.
• Infections: HIV, hepatitis.
• Systemic Diseases: Lupus, diabetes, sickle cell anaemia.
• Cancers: Rare cases like leukaemia or lymphoma.

Risk Factors of Nephrotic Syndrome

Several factors can increase the likelihood of developing nephrotic syndrome, including:

• Age, as it is more common in older adults
• Ethnicity, with FSGS being more prevalent in Black adults and membranous nephropathy in white adults
• Underlying conditions such as diabetes, lupus, or infections like HIV
• Genetic predisposition, as some forms of nephrotic syndrome may have genetic components

Complications of Nephrotic Syndrome

If left untreated, nephrotic syndrome can lead to several complications, such as:

• Blood clots, particularly venous thrombosis in the deep veins of the lower limbs and renal veins, which can lead to pulmonary embolism
• Increased risk of infections due to the loss of immunoglobulins
• Development or worsening of high blood pressure (hypertension)
• Kidney failure, which can be brief or long-lasting, including chronic kidney disease

Diagnosis of Nephrotic Syndrome

Diagnosing nephrotic syndrome involves a combination of tests, including:

• Urine tests: Urinalysis detects albuminuria; 24-hour collection measures protein loss.
• Blood tests: Assess albumin, blood protein, and kidney function (creatinine, urea nitrogen).
• Kidney biopsy: Identifies underlying causes via tissue sample analysis.
• Additional tests: Includes HIV screening, hepatitis serology, protein electrophoresis, and antinuclear antibodies for secondary causes.

Treatment for Nephrotic Syndrome

Treatment for nephrotic syndrome focuses on addressing its underlying cause, alleviating symptoms, and preventing complications. Common treatment options include:

• Diuretics: Help reduce water retention and control swelling.
• ACE inhibitors and ARBs: Lower blood pressure and reduce protein loss in urine.
• Anticoagulants: Reduce the risk of blood clots.
• Cholesterol-lowering medications: Statins manage high cholesterol.
• Steroids and immunosuppressants: Reduce inflammation and suppress the immune system.
• Albumin injections: Replace lost proteins in congenital cases.
• Dialysis or kidney transplant: For severe cases with compromised kidney function.

Prevention of Nephrotic Syndrome

Taking proactive steps can help reduce the risk of nephrotic syndrome and its associated complications. Key preventive measures include:

• Control blood pressure and diabetes: Maintain healthy blood pressure and blood sugar levels to protect kidney health.
• Vaccinations: Stay updated on vaccines, particularly for infections like hepatitis and pneumococcal disease.
• Complete antibiotic courses: Always finish prescribed antibiotics to prevent recurring infections.
• Avoid certain medications: Use caution with drugs like NSAIDs that may harm kidney function.

When to See a Doctor

Promptly consulting a doctor is crucial for managing nephrotic syndrome effectively. Seek medical care in the following situations:

• If symptoms worsen or new symptoms appear, such as increased swelling, protein in the urine (proteinuria), or changes in urine output.
• If you experience signs of infection, blood clots (thrombosis), or other complications.
• For regular check-ups to monitor kidney function and manage underlying conditions.

Conclusion

Nephrotic syndrome is a complex condition that requires comprehensive management. Treatment focuses on addressing the underlying cause, managing symptoms, and preventing complications. While some causes cannot be prevented, controlling blood pressure and diabetes and staying vaccinated can help mitigate the risk. Regular medical check-ups are crucial for early detection and effective management of this condition. By understanding the types, causes, symptoms, and treatments, individuals can better navigate and manage nephrotic syndrome.

Frequently Asked Questions (FAQs)

References

• https://pmc.ncbi.nlm.nih.gov/articles/PMC10924861
• https://www.mdpi.com/2227-9059/12/3/569
• https://www.aafp.org/pubs/afp/issues/2016/0315/p479.html
• https://www.amjmed.com/article/0002-9343(47)90036-3/abstract
• https://www.thelancet.com/clinical/diseases/nephrotic-syndrome