When Should The Chance Of An Exceedingly Rare Disease Disqualify A Kidney -- For Donation?

That is the fascinating, and difficult question raised in today's New York Times story on two separate kidney-transplant patients that appear to have contracted a very rare infection, from an individual donor-source. [Strictly speaking, this item strays from the core topic this blog covers, as neither Schering-Plough, nor Merck makes any kidney transplantation instrument, kit, device or anti-rejection drug.]

With the well-documented shortages in available kidneys, the questions include risk-to-benefit assessments, as well as informed consent possibilities. Should a donated kidney be implanted -- once the consenting patient is warned of the potential for a disease -- given that it is not really feasible to screen each donated organ for every remotely-possible potential bacterial or other problem? Do go read it all -- as it is quite thought-provoking.

From The New York Times story -- a snippet, then:

. . . .All the tests were negative, so [this donor's] heart, liver and kidneys were transplanted into four patients. Afterward, an autopsy still missed the infection and seemed to support the mistaken diagnosis.

About three weeks after the transplants, both kidney recipients became severely ill, within hours of each other, with seizures, fever and changes in their mental status. They were taken back to the hospital in Jackson. A doctor there noted that both had had kidney transplants the same day. He suspected immediately that the kidneys had come from the same donor and that the donor might have had an undetected infection.

The hospital sent samples of the donor’s brain tissue to the disease centers, which found an amoeba called Balamuthia mandrillaris. One kidney patient was then given a biopsy, which also tested positive for the amoebas. Balamuthia lives in soil and water, and scientists suspect that people become infected through cuts or from ingesting the organism. Only about 70 cases have ever been identified in the United States, and nearly all have been fatal. These are the first known cases from transplants.

It was not clear why only the kidney patients had become ill. The kidneys may have harbored more amoebas than the other organs, Dr. Farnon said, or the particular anti-rejection drugs might have been a factor.

The patients are being treated with “a boatload of drugs,” Dr. Schlessinger said, but have not improved. . . .

I think it likely that the anti-rejection drugs (with their generally salutory by-design immune supression properties -- to decrease chances of organ rejection) were, in part, a cause here. But if the alternative was to die of end stage renal disease, I am perplexed, but leaning toward the notion that this was all a risk worth assuming.

^{[Note: My image, above right, as re-imagined and heavily-edited from a Canadian educational site on medicine, and kidney transplantation.]}