Answer Man: Will one kidney do the work of two?

News-DemocratJuly 26, 2013 

Q. Everyone is born with two kidneys. Does each kidney work at 100 percent, i.e., equaling 200 percent, or do they work at 50 percent each, thereby equaling 100 percent? What I'm asking is if one were to fail or, say, were transplanted, would the remaining kidney work at 50 percent or 100 percent? -- R.C., of Glen Carbon

A. Let me start with a shocker for you and many others: Not everyone is born with two kidneys -- not by a long shot.

About one of every 750 people comes into this world with only one, according to DaVita, a leading provider of dialysis and other kidney care in the U.S. So, in the metro-east alone, there could be several hundred perfectly healthy people walking around with just a single kidney.

It's a condition called "renal agenesis" and some people don't even realize it until it's discovered on an X-ray or other medical test later in life. (Trivia fact: Usually it's the left one that's missing, DaVita says.)

But because of the marvels of the human body, people can do just fine without it. Usually, so do those who donate a kidney for a transplant. Even many who have one kidney fail might continue a reasonably normal life. Here's why, according to information that Dr. Marie Philipneri, an associate professor of internal medicine/nephrology at St. Louis University, sent me:

Most people are born with two healthy kidneys, and, between them, they share the work of filtering the blood, removing wastes -- even producing a few hormones. I suppose you could say they each do about 50 percent of the work.

Hence, say after a donation, you'd expect to see an immediate drop of 50 percent in kidney function after losing half of your kidney tissue. For you medical geeks, kidney function is based on the glomerular filtration rate (GFR), which shows how well the kidneys are filtering out waste products. Removing one kidney means the remaining kidney has to do the work of two, so you'd expect to see an immediate and significant drop in the GFR.

But here's where the amazing restorative powers of the body come in: Within a year, the remaining kidney will increase its GFR as much as 50 percent to where that single kidney is doing up to 75 percent of the work that the two used to do together. And, to handle the increased load, the remaining organ will grow in physical size -- about 20 percent, according to Drs. Bryan and Yolanda Becker, two Chicago-area doctors involved in transplant surgery.

Put all of that together, and most people with one kidney can live a normal life. Now, there are some caveats: People with one kidney may be at more risk for high blood pressure and they should keep tabs on their GFR and the amount of protein in their urine. They also may want to avoid contact sports or other activities that could injure the remaining organ.

But in studying 50,000 kidney donations from 1987 to 2002, the Organ Procurement and Transplantation Network found that only 56 donors had their remaining kidney fail -- even though we also lose about 1 percent of kidney function each year after we hit 40.

Experts hope all of these facts offer reassurance to anyone contemplating becoming an organ donor. After all, about 100,000 people currently are on a kidney transplant list -- and about a dozen are dying each day for lack of a new organ.

Wheely good group: My apologies to Al Hogg, Dennis Korte, et al., for being unaware of a metro-east group that also welcomes the donation of old, unused bicycles so they can be refurbished and given to disadvantaged kids.

Four years ago, Hogg and his wife, Rose, organized Cycle of Giving. Its mission, I'm told, is to repair and give bikes to needy children who earn them by reading a book and writing a report, thus promoting both mental and physical fitness.

You'll find them every other Saturday morning at Belleville's Old Town Market, where they also provide minor bike repairs and donated books, Linda Malone tells me. They also have sponsored special events in East St. Louis, Fairmont City and Granite City

For more information, look up Cycle of Giving on Facebook. You're sure to like it.

Today's trivia

Who was the first black man nominated as a presidential candidate?

Answer to Thursday's trivia: It seems hard to imagine that anyone who won a Major League Baseball seasonal batting crown could do so without hitting at least one home run, but it has happened twice since the American League claimed Major League status in 1901. You may not have heard of one of them: In 1918, Zachariah "Buck" Wheat, left fielder for the Brooklyn Superbas, led the National League with a .335 average without a single dinger. Then, in 1972, Minnesota infielder Rod Carew did the same in the American League -- a league-leading .318 average sans round-tripper. And before the modern era, the Baltimore Orioles' Willie Keeler hit an eye-popping .424 in 1897 - again without a home run.

Send your questions to Roger Schlueter, Belleville News-Democrat, 120 S. Illinois St., P.O. Box 427, Belleville, IL 62222-0427 or rschlueter@bnd.com or call 239-2465.

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