Nephrotic syndrome is a kidney condition caused by damage to the glomeruli, the kidneys’ tiny filtering units. This damage makes them “leaky,” allowing large amounts of protein to escape from the blood into the urine, a defining feature called proteinuria. The resulting low protein levels in the blood can lead to significant swelling (edema) in the legs, ankles, and around the eyes, as well as foamy urine. The primary goal of treatment is to stop this protein leakage and induce remission.
Defining and Achieving Remission
Remission is defined by a significant reduction or normalization of protein in the urine, measured by a urine protein-to-creatinine ratio (UPCR). Complete remission is a UPCR of less than 0.2 g/g (or 20 mg/mmol), or a dipstick reading of negative or trace protein for three consecutive days. This indicates the kidney filters have healed and are no longer leaking large amounts of protein.
Partial remission occurs when proteinuria has decreased significantly but has not yet returned to normal. This is characterized by a UPCR below the nephrotic range threshold (less than 2.0 g/g) but above the level for complete remission. Achieving remission is the focus of treatment, as sustained proteinuria can lead to further kidney damage and other complications.
Corticosteroid therapy is the primary treatment for inducing remission, especially for minimal change disease, the most common form in children. Medications like prednisone suppress the body’s immune system. In many idiopathic (of unknown cause) cases, the immune system is believed to mistakenly damage the glomeruli. Dampening this immune response reduces kidney inflammation, allowing the filters to function properly.
For individuals with steroid-resistant conditions or frequent relapses, other immunosuppressive medications are used. These second-line therapies include calcineurin inhibitors like tacrolimus and cyclosporine, or mycophenolate mofetil. These drugs modulate the immune system through different mechanisms, offering alternative pathways to achieve remission.
Life During Remission
Once remission is achieved, life involves a new routine focused on maintaining kidney health. A component of this is at-home monitoring using urine dipsticks to test for protein each morning. This simple test allows for the early detection of proteinuria, which could signal a relapse, enabling prompt communication with a nephrologist.
Dietary adjustments are common during remission. A low-sodium diet is advised to manage fluid retention and maintain healthy blood pressure, often limiting intake to under 2,000 milligrams per day. This means avoiding processed foods, canned goods, and high-salt snacks. A high-protein diet is not recommended in remission, as a normal, balanced intake is sufficient and avoids straining the kidneys.
Discontinuing medication, especially corticosteroids, is a carefully managed phase of remission. Doctors prescribe a specific tapering schedule, gradually reducing the dose over weeks or months. Following this schedule is important, as abruptly stopping steroids can cause side effects and increase the risk of a relapse. This slow reduction allows the body to readjust safely.
Understanding Relapse
A relapse is the return of significant proteinuria after a period of remission, confirmed when a urine dipstick shows high protein levels (3+ or greater) for three consecutive days. Relapses are a common feature of nephrotic syndrome, particularly in children with steroid-sensitive minimal change disease. A relapse is not a sign of treatment failure but part of the condition’s natural course for many patients.
The most frequent trigger for a relapse is an infection, such as a common viral illness like an upper respiratory tract infection. The body’s immune response while fighting the virus can become dysregulated and trigger the initial kidney inflammation. For this reason, families are advised to be vigilant with urine testing when a child is sick. Other triggers can include allergic reactions or other events that stimulate the immune system.
Managing a relapse involves following a pre-established plan from a nephrologist. For most individuals with steroid-sensitive cases, this means restarting a course of prednisone. The goal is to control the immune system, stop the proteinuria, and re-establish remission. A clear plan allows treatment to begin at the first confirmed signs of relapse, often preventing severe edema and hospitalization.
Long-Term Outlook and Management
The long-term outlook depends on the underlying cause of the condition and its response to treatment. For most children with minimal change disease, the prognosis is very good. While they may experience relapses throughout childhood, these episodes become less frequent over time. Many children with this form outgrow it by their late teens and remain in permanent remission.
For other forms of nephrotic syndrome, such as focal segmental glomerulosclerosis (FSGS), the prognosis is more variable. These types can be more resistant to standard treatments and may lead to a gradual decline in kidney function. However, medical advancements and immunosuppressive therapies can help manage the condition, preserve kidney function, and maintain quality of life.
Long-term management requires consistent follow-up care with a nephrologist. Regular appointments are necessary to monitor kidney function through blood tests, check for proteinuria, and manage blood pressure. This partnership between the patient and their medical team is for navigating the disease, adjusting treatments as needed, and ensuring the best possible health outcomes.