C3 Glomerulonephritis: Causes, Diagnosis, and Treatment Options

When your C3 glomerulonephritis, a rare kidney disease caused by uncontrolled activation of the complement system, leading to inflammation and damage in the glomeruli. It's also known as C3GN, and unlike other kidney conditions, it doesn't usually involve antibodies—it's all about your body's own immune system going rogue. This isn't just high blood pressure or protein in the urine. It's a deeper problem: your complement system, a group of proteins meant to fight infection, starts attacking your kidneys instead.

This disease often shows up in young adults or children, but it can hit anyone. You might notice swelling in your legs, foamy urine, or unexplained fatigue. The only way to know for sure is a renal biopsy, a procedure where a small sample of kidney tissue is taken to examine under a microscope for signs of C3 glomerulonephritis. Blood tests will show low C3 levels—sometimes normal C4—which helps doctors rule out lupus or other autoimmune issues. It’s not something you can guess from symptoms alone.

What makes C3 glomerulonephritis tricky is that it’s not one single disease. It sits on a spectrum, sometimes overlapping with dense deposit disease. Some people have slow progression; others lose kidney function fast. There’s no cure, but treatments can slow it down. immunosuppressants, medications that calm the overactive immune response to reduce kidney damage in C3 glomerulonephritis like mycophenolate or cyclophosphamide are used, though results vary. Newer drugs targeting the complement system—like eculizumab or factor D inhibitors—are showing promise in trials, but they’re expensive and not yet standard.

You won’t find this condition in every doctor’s office. Many patients go years with misdiagnoses—thought to have IgA nephropathy or just "chronic kidney disease." That’s why knowing the signs matters. If you’ve been told your kidney issue has no clear cause, ask about C3 glomerulonephritis. Get the biopsy. Check your complement levels. This isn’t about panic—it’s about precision.

The posts below cover what actually works in managing this condition. You’ll find real-world advice on monitoring kidney function, handling side effects of immunosuppressants, understanding blood test results, and how lifestyle choices like diet and blood pressure control make a difference. Some stories are from patients who stabilized their disease. Others show why certain treatments fail. There’s no fluff—just what the data and experience show.