Diseases of the Kidney Filters

Problems with glomeruli (tiny blood vessels that filter wastes and water out of the blood) are the number three cause of kidney disease. Ten types cause 8.2% of kidney failure in the U.S.1 We’ll tell you about the 5 most common ones, below:

  1. Glomerulonephritis (GN) is inflammation of the glomeruli that can be a short or a long-term problem. You may have dark brown or foamy urine, and high blood pressure is common with GN. GN is also called Bright’s disease.
  2. FSGS2 (focal segmental glomerulosclerosis) scars the glomeruli. Protein and blood then leak into the urine, which may be foamy or pink. The cause of FSGS is not known. A needle biopsy of your kidney may find FSGS — or may not catch it on the first try. About half of people with FSGS will have kidney failure.3 A fast-moving type can cause kidney failure in two to three years; for most, it takes 5-20 years.
  3. IgA nephropathy (Berger’s disease) causes protein (immunoglobulin A) to deposit in the kidney blood vessels. No one knows why, though it can run in families. IgA nephropathy tends to cause high blood pressure and swelling. It moves quite slowly; about 1 in 4 will go on to kidney failure over 25 years.4
  4. Membranous nephropathy (MN) thickens the walls of the glomerular blood vessels. It may occur on its own or as a result of other disease. Blood clots are more likely, so blood thinners may be prescribed. MN often goes away for years — or even for good. About 1 in 5 will have kidney failure.5
  5. MPGN (membranoproliferative glomerulonephritis) causes immune cells to deposit in the kidney blood vessels. This changes the vessels so they don’t work as well. It can cause high blood pressure, swelling, and dark urine that looks like tea or may be cloudy. About half the time, MPGN will go on to kidney failure in 10 years or so.6 Cases that are mild at the start may be less likely to cause kidney failure.7

What You Can Do

Glomerular disorders often affect young people with many years ahead of them. It’s key to take steps to avoid heart disease, which can go along with kidney problems. You’ll see a number of tips below:

  • Consider immune suppressant drugs for FSGS, MPGN, and IgA nephropathy. About half the time, drugs to suppress the immune system can slow kidney damage in FSGS.8 These drugs include steroids and some cancer fighting drugs. When protein is spilled into the urine, these drugs may be of use.9
  • Reduce cholesterol to help fight membranous or IgA nephropathy. Both of these diseases can raise cholesterol levels by acting on the liver. Statin drugs to lower cholesterol can help protect your kidneys — especially if you have heart disease, too.10
  • Keep your blood pressure low. This will reduce the stress on your kidneys.
  • Ask your doctor about limiting salt and fluids. This can help fight edema, swelling or shortness of breath caused by a build up of fluid in your tissues.
  • Eat a lower protein diet to reduce waste build up. Americans tend to eat a lot of protein. In some cases, cutting back a bit can ease the burden on your kidneys. Ask to talk to a dietitian — you need good nutrition, too.
  • Avoid known kidney toxins.

Questions to Ask Your Doctor if You Have a Glomerular Disease

  1. What is the name of my condition?
  2. Can you tell whether my disease will progress to kidney failure or not? When?
  3. Will immune suppressing drugs be useful in my case?
  4. If so, what are the side effects of these drugs?
  5. Would an ACE-inhibitor be a good choice to help me control my blood pressure?
  6. Are there alternative treatments, like fish oil, that might help my problem? (Some studies have found it useful for IgA nephropathy, but others have not.)
  7. Can you check the level of uric acid in my blood? (High levels predict that IgA nephropathy will progress.)

Links to Learn More

1 USRDS 2006 ADR, table A.7 2 http://www.niddk.nih.gov/patient/fsgs/fsgs.htm 3 http://www.nlm.nih.gov/medlineplus/ency/article/000478.htm 4 Chan JC, Trachtman H. Modulating the progression in IgA nephropathy. Nephron Clin Pract . 2006;104(1):c61-8 5 http://www.nlm.nih.gov/medlineplus/ency/article/000472.htm 6 http://www.nlm.nih.gov/medlineplus/ency/article/000475.htm 7 Cansick JC, Lennon R, Cummins CL, Howie AJ, McGraw ME, Saleem MA, Tizard EJ, Hulton SA, Milford DV, Taylor CM. Prognosis, treatment, and outcome of childhood mesangiocapillary (membranoproliferative) glomerulonephritis. Nephrol Dial Transplant . 2004 Nov;19(11):2769-77 8 http://www.kidney.org/atoz/atozItem.cfm?id=63 9 DS, Brown CB. Therapeutic approach of patients with IgA nephropathy. Ren Fail . 2004 Mar;26(2):171-7 10 Sandhu S, Wiebe N, Fried LF, Tonelli M. Statins for improving renal outcomes: a meta-analysis. J Am Soc Nephrol . 2006 Jul;17(7):2006-16