Membranous nephropathy

Membranous nephropathy (MEM-bruh-nus nuh-FROP-uh-thee) occurs when the small blood vessels in the kidney (glomeruli), which filter wastes from the blood, become inflamed and thickened. As a result, proteins leak from the damaged blood vessels into the urine (proteinuria). For many, loss of these proteins eventually causes signs and symptoms known as nephrotic syndrome.

In mild cases, membranous nephropathy may get better on its own, without any treatment. As protein leakage increases, so does the risk of long-term kidney damage. In many, the disease ultimately leads to kidney failure. There's no absolute cure for membranous nephropathy, but successful treatment can lead to remission of proteinuria and a good long-term outlook.

Symptoms Causes Risk factors Complications

Membranous nephropathy usually develops gradually, so you may not suspect that anything is wrong. As you lose protein from your blood, swelling in your legs and ankles and weight gain from excess fluid can occur. Some people experience lots of swelling from the very beginning of the disease, and others may not have any severe symptoms until they have advanced kidney disease.

Signs and symptoms of membranous nephropathy include:

  • Swelling in the legs and ankles
  • Weight gain
  • Fatigue
  • Poor appetite
  • Frothy urine
  • Elevated fat levels in the blood (hyperlipidemia)
  • Increased protein levels in the urine (proteinuria)
  • Decreased protein levels in the blood, particularly of the protein albumin

When to see a doctor

If you have blood in your urine, persistent swelling in your legs and ankles, or increased blood pressure, make an appointment to see a doctor.

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