What Is Nephrotic Syndrome? Symptoms, Causes, and Treatment Options Explained

Nephrotic syndrome is a kidney disorder characterized by a specific set of clinical features, the most prominent being excessive protein loss in the urine. Medically, this is defined as a 24-hour urinary protein excretion exceeding 3.5 grams. Alongside this, patients typically exhibit hypoalbuminemia, with plasma albumin levels dropping below 30 g/L. These biochemical abnormalities disrupt the body's fluid balance, leading to noticeable symptoms.

Common Signs and Physical Manifestations

One of the hallmark signs of nephrotic syndrome is edema, particularly in the lower extremities such as the legs and ankles. As fluid accumulates due to low blood protein levels, swelling can become more widespread. In severe cases, patients may develop fluid buildup in critical areas—such as pleural effusion (fluid around the lungs), ascites (abdominal fluid), or even pericardial effusion (fluid around the heart). These conditions can lead to shortness of breath, abdominal discomfort, and in rare instances, cardiac complications.

Associated Metabolic Abnormalities

Beyond protein imbalance, individuals with nephrotic syndrome often experience significant lipid disturbances. This includes elevated total cholesterol and increased levels of low-density lipoprotein (LDL), commonly referred to as "bad cholesterol." This condition, known as hyperlipidemia, not only reflects kidney dysfunction but also raises long-term cardiovascular risks, making it an important focus during treatment and monitoring.

Underlying Kidney Diseases That Cause Nephrotic Syndrome

Nephrotic syndrome is not a single disease but rather a clinical presentation resulting from various underlying kidney pathologies. The most frequently identified causes include:

Minimal Change Disease

This is especially common in children and often responds well to corticosteroid therapy. Despite significant proteinuria, kidney biopsy may show minimal structural changes under a light microscope.

Focal Segmental Glomerulosclerosis (FSGS)

A leading cause in adults, FSGS involves scarring in certain segments of the kidney's filtering units. It tends to be more resistant to treatment and carries a higher risk of progressing to chronic kidney disease.

Membranous Nephropathy

Often seen in middle-aged and older adults, this condition results from immune complex deposits thickening the glomerular membrane. It is one of the most common causes of adult-onset nephrotic syndrome.

Membranoproliferative Glomerulonephritis (MPGN)

This less common form involves both thickening and increased cellularity in the glomeruli, usually linked to autoimmune or chronic infectious conditions.

Treatment Approaches Based on Diagnosis

Effective management of nephrotic syndrome depends heavily on identifying the precise underlying pathology through kidney biopsy. Standard treatment protocols often involve immunosuppressive therapies tailored to the specific diagnosis.

Corticosteroids, such as prednisone, are commonly prescribed, especially for minimal change disease and some forms of FSGS. They are frequently combined with other immunosuppressants like cyclophosphamide, tacrolimus, or cyclosporine to enhance response and reduce relapse rates.

In cases of membranous nephropathy, newer biologic agents have revolutionized treatment. Rituximab, a monoclonal antibody that targets B cells, has shown high efficacy in inducing remission and is increasingly used as a first-line option, particularly for patients who are at high risk or intolerant to traditional drugs.

Managing Complications and Long-Term Risks

Patients with nephrotic syndrome face several serious complications that require proactive prevention and monitoring. Due to weakened immunity from protein loss and medication side effects, they are highly susceptible to infections, including bacterial pneumonia and spontaneous peritonitis.

Another major concern is the increased risk of thromboembolic events, such as deep vein thrombosis (DVT) or pulmonary embolism. This stems from the imbalance of clotting factors in the blood caused by the syndrome itself. Doctors may recommend anticoagulant therapy in high-risk cases.

Finally, progressive kidney damage can lead to chronic kidney disease or renal failure. Regular follow-ups, blood pressure control, dietary adjustments (like reduced salt and protein intake), and tight management of cholesterol are essential components of long-term care.

Early diagnosis, personalized treatment, and comprehensive monitoring significantly improve outcomes for individuals living with nephrotic syndrome. With advances in immunology and targeted therapies, many patients now achieve remission and maintain a good quality of life.