Serious Kidney Injury Common in Very Ill H1N1 Patients

Orlando, FL (April 14, 2010) — People who got very sick in the recent H1N1 influenza A epidemic often suffered kidney damage as well as respiratory illness, according to research being presented here today at the National Kidney Foundation's Spring Clinical Meetings.

"It's concerning that so many people got some form of kidney injury, although it was reversible in the majority of them," said Dr. Manish M. Sood, an assistant professor of medicine at the University of Manitoba in Winnipeg and director of hemodialysis at St. Boniface General Hospital. "Patients who come to the ICU with critical illness who also have kidney injury stay longer, take up more resources and have a much higher chance of dying."

Any type of serious infection or critical illness can cause kidney injury, according to Dr. Sood. Often during critical illness, a person's blood pressure drops, inflammation begins, and the blood vessels to and from the kidneys constrict, decreasing blood flow. "Viral infections like influenza have one added kicker in that they cause muscle breakdown," he explained. "The byproduct of that is directly toxic to kidney tubules." Kidney tubules are a key part of the organ's blood filtering system.

To investigate how H1N1 influenza A infections might affect the kidneys, Dr. Sood and his team looked at 50 critically ill patients admitted to one of seven intensive care units in Manitoba during the pandemic. H1N1 was confirmed in 47 of the patients.

Two-thirds had kidney injury or kidney failure, the researchers found, while 11 percent needed to undergo dialysis to help filter their blood. Sixteen percent of the patients died. The patients who had kidney failure were over 11 times more likely to die than those whose kidneys kept functioning, while the patients who needed dialysis spent significantly longer in the hospital.

Because the study included relatively few patients in a single Canadian province, it may not be generalizable to all patients with serious H1N1 infections, Dr. Sood said. Nevertheless, he added, they show that doctors treating these patients should be aware of the possibility of kidney damage and avoid it, if possible, by making sure patients don't get dehydrated, and by not giving them substances that could harm the kidneys such as contrast agents used in imaging.

And, Dr. Sood said, the findings also underscore the importance of getting immunized against the flu. "Getting the vaccine could limit severe illness, which could limit this kidney injury that can occur."

The National Kidney Foundation is dedicated to preventing and treating kidney and urinary tract diseases, improving the health and well being of individuals and families affected by these diseases and increasing availability of all organs for transplantation.

For more information about organ donation, transplantation and dialysis contact the National Kidney Foundation at www.kidney.org.