Membranous nephropathy

Membranous nephropathy (MN) is a progressive kidney disease characterized by thickening of the glomerular basement membrane, which ultimately leads to the development of nephrotic syndrome. Autoimmune mechanisms play a major role in the pathogenesis of MN. As a result of the destruction of podocyte cells, inflammatory processes are activated, leading to proteinuria, edema, and increased blood lipid levels. Currently, it is believed that the disease affects patients of different age categories, but the greatest prevalence is observed in people over 40 years of age.

History of the disease and interesting historical facts

Membranous nephropathy was first described in 1957 by English-speaking researchers who became the founders of the study of this disease. They initially noted its association with various infections and systemic diseases such as systemic lupus erythematosus. Over the following decades, various associated factors were identified, including various drugs that can cause the development of MN. Historical studies have shown that membranous nephropathy can be either primary or secondary, with the latter cases most often due to comorbidities.

Epidemiology

Membranous nephropathy occurs with a frequency of 5-10 cases per 100,000 population per year. Currently, there is an increase in the incidence, possibly due to improved diagnostics and awareness of this disease by doctors. According to statistics, MN is more common in men than in women, which may be due to differences in the immune response between the sexes. The ratio of men to women is approximately 2:1. Membranous nephropathy is most common among patients aged 30 to 60 years, which makes it relevant for practical nephrology.

Genetic predisposition to this disease

There is evidence that points to a genetic predisposition to membranous nephropathy. In particular, certain gene polymorphisms have been identified that may increase the risk of developing the disease. In particular, the following genes have been studied:

• HLA-DRB1 – associated with increased susceptibility to kidney disease.
• PLA2R – antibodies to this receptor were detected in the majority of patients with primary membranous nephropathy.
• THSD7A – also participates in the pathogenesis of gallon MN.

These gene mutations may contribute to abnormalities in the immune system, increasing the risk of developing membranous nephropathy.

Risk factors for the development of this disease

Risk factors for membranous nephropathy include the following:

• Infectious agents – such as hepatitis B and C viruses, as well as syphilis.
• Medicines – the use of non-steroidal anti-inflammatory drugs, antibiotics and some antitumor agents can provoke the development of MN.
• Systemic diseases – for example, systemic lupus erythematosus, diabetic nephropathy.
• Environmental factors – long-term exposure to toxic substances, such as arsenic or lead.

These factors increase the likelihood of developing membranous nephropathy and may cause its recurrence.

Diagnosis of this disease

Diagnosis of membranous nephropathy is based on clinical manifestations and laboratory tests. The main symptoms that may indicate this disease are:

• Proteinuria is the excretion of protein in the urine in quantities greater than 3-3.5 g/day.
• Puffiness - increasing swelling, especially around the eyes and legs.
• Hyperlipidemia is elevated levels of cholesterol and triglycerides.

Laboratory tests play an important role in the diagnosis of:

• Analysis of urine – detection of protein, erythrocytes and cylinders.
• Biochemical blood test – assessment of creatinine, electrolytes and lipids levels.

Radiological examinations are usually not of primary importance in the diagnosis of MN, but can be used to exclude other diseases. Renal biopsy is the "gold standard" of diagnosis. Biopsy reveals membrane thickening and immune complex deposits.

Differential diagnosis must be made with other forms of nephropathy, such as glomerulonephritis and diabetic nephropathy.

Treatment

Treatment of membranous nephropathy is aimed at reducing symptoms and preventing disease progression. Common approaches include:

• Removing or changing risk factors – for example, discontinuation of drugs that cause nephropathy.
• Normalization of blood pressure – use of antihypertensive drugs.

Pharmacological treatment includes:

• Corticosteroids – Prednisolone is the drug of first choice.
• Immunosuppressants – use of cyclophosphamide or mycophenolate mofetil to reduce the activity of the immune system.

In some cases, if the disease has progressed significantly, surgical treatment, including kidney transplantation, may be required.

Other treatments may include kidney support and diet.

List of medications used to treat this disease

Drugs used to treat membranous nephropathy include:

• Prednisolone – to reduce inflammation.
• Cyclophosphamide – to suppress the immune response.
• Mycophenolate mofetil – to provide an immunosuppressive effect.
• Losartan – to protect the kidneys and control blood pressure.
• bisoprolol – for the management of arterial hypertension.

Disease monitoring

Monitoring of membranous nephropathy includes regular examinations and monitoring of the patient's condition. The key stages of monitoring are:

• Evaluation of urine protein levels – control of proteinuria.
• Regular blood tests – to monitor kidney function and lipid levels.
• Help in case of complications – early diagnosis and treatment of complications such as thrombosis.

The prognosis depends on the severity of the disease and its response to therapy. Complications may include chronicity of the process, development of renal failure or thrombus formation.

Age-related features of the disease

The manifestations of membranous nephropathy may vary depending on the patient's age category.

• In children – the disease often progresses acutely and requires early diagnosis.
• In young people – MN may be associated with autoimmune processes; research into systemic diseases is necessary.
• In older people – various concomitant pathologies are more often observed, which complicates diagnosis and treatment.

Age factors play an important role in the choice of therapy and approaches to patient management.

Questions and Answers

• What is membranous nephropathy? Membranous nephropathy is a kidney disease characterized by thickening of the glomerular basement membrane, which leads to the development of nephrotic syndrome.
• What are the main risk factors for membranous nephropathy? Risk factors include infectious agents, drugs, systemic diseases and the environment.
• What diagnostic methods are used for membranous nephropathy? The main diagnostic methods include urine analysis, blood biochemistry, kidney biopsy and radiological examinations.
• How is membranous nephropathy treated? Treatment includes risk factor management, pharmacological therapy, and, in some cases, surgery.
• What is the prognosis for membranous nephropathy? The prognosis depends on the severity of the disease and its response to therapy; development of chronic renal failure or thrombosis is possible.