Minimal Change Disease: A Kidney Condition with Low Risk of Progression to Uremia

Minimal change disease (MCD) is the most common cause of nephrotic syndrome in children, accounting for approximately 90% of cases, particularly in those under 10 years old. In other words, about nine out of ten children with nephrotic syndrome have MCD. In adults, however, MCD is less common, making up only 10–15% of nephrotic syndrome cases. The most frequent cause in adults is membranous nephropathy, which we discussed in a recent article: Despite heavy proteinuria, this kidney disease can have a decent prognosis. Today, let’s explore MCD with Kidney Online!

MCD: Subtle Changes, Significant Impact

As its name suggests, MCD involves subtle changes in the kidney. If a small sample of kidney tissue from an MCD patient is examined, it appears normal under a standard optical microscope, indistinguishable from healthy tissue. Only an electron microscope, capable of magnifying fine structures, reveals the hallmark of MCD: widespread fusion of podocyte foot processes. Hence, the term “minimal change” disease.

Subtle Pathology, Striking Symptoms

Despite its subtle pathology, MCD presents with pronounced symptoms, often appearing suddenly a few days or weeks after an upper respiratory or systemic infection. These include:

1. Heavy Proteinuria: Nearly all MCD patients exhibit proteinuria exceeding 3.5 g/day, sometimes surpassing 15–20 g/day. Unlike other nephrotic syndrome causes, such as membranous nephropathy or FSGS, where proteinuria develops gradually over months, MCD’s heavy proteinuria emerges rapidly and abruptly.
2. Hypoalbuminemia: Blood tests show albumin levels below 30 g/L, sometimes dropping below 20 g/L.
3. Weight Gain and Edema: Swelling occurs due to fluid retention.
4. Hyperlipidemia: Blood cholesterol levels rise significantly.
5. Elevated Creatinine: Some children and adults experience a mild 30–40% increase in blood creatinine at onset, which is typically reversible.

Diagnosing MCD requires a kidney biopsy for confirmation. However, since most cases of nephrotic syndrome in children are MCD, a biopsy is often unnecessary; clinical symptoms alone suffice for diagnosis and treatment initiation. Only children unresponsive to steroids may require a biopsy for further clarity. In adults, nephrotic syndrome is more complex, typically necessitating a biopsy to confirm the diagnosis before treatment.

Treatment and Prognosis of MCD

Glucocorticoids, such as prednisone, are the first-line treatment for MCD. Most children see their proteinuria resolve within two months of starting steroids. In adults, however, remission is slower—over 25% of steroid-responsive adults require 3–4 months or longer to achieve complete remission. Thus, the timeline for assessing steroid effectiveness differs: adults need more patience than children.

During steroid tapering, relapse is most likely when the dose is reduced to around four tablets. At this stage, slow tapering is crucial. Patients must strictly follow medical advice, avoid unauthorized dose reductions, and take precautions to:

1. Prevent infections.
2. Avoid allergens, such as pollen, dust mites, pet dander, or foods that trigger intolerance, as these can precipitate relapse.

After achieving complete remission (negative proteinuria), some patients may experience one or more relapses. Initial treatment protocols can be reused, but for steroid-resistant or frequently relapsing cases, second-line treatments like immunosuppressive agents (e.g., cyclophosphamide, cyclosporine, or tacrolimus) may be considered.

MCD has an excellent prognosis. Most patients maintain remission with steroids or immunosuppressants, with only a tiny fraction progressing to uremia. While some experience elevated creatinine during acute episodes, this is typically reversible, and levels normalize after proteinuria resolves. Once proteinuria fully remits, the kidney’s pathological changes often return to normal, making MCD a potentially curable kidney disease.

MCD comes on quickly, remits quickly, but also relapses frequently. For parents and patients, the challenge lies not in kidney failure but in managing the side effects of medications. Patience and confidence are essential. Instead of dwelling on frustration, invest time in learning about kidney disease to support early recovery.