Former Israeli Prime Minister Ariel Sharon was rushed to the intensive care unit of a Tel Aviv hospital Wednesday to undergo a form of kidney dialysis, a hospital spokeswoman said.

Sharon's condition deteriorated significantly earlier in the week, when officials at the Sheba Medical Center said the former leader's kidneys were failing and that they had noticed changes in his brain membrane.

Sharon, 78, has been in a coma since suffering a massive stroke on Jan. 4.

His blood will be filtered to remove the excess fluids accumulating in his body as a result of the kidney failure, the hospital said. He also is receiving antibiotics intravenously to treat a bacterial infection in his blood.

CountryWatch: Israel

Hospital spokeswoman Anat Dolev declined to answer further questions.

Dr. John Martin, a professor of cardiovascular medicine at London's University College, said the infection in Sharon's blood indicates his immune system is weak, and the problem could damage other vital organs, such as the liver.

Normally, doctors do not treat patients in Sharon's condition, Martin said. However, the dialysis and antibiotics could keep Sharon alive for weeks or even months, he said.

"The best thing might be to allow Ariel Sharon to die by not doing this kidney dialysis and that is considered ethical throughout the world," Martin said.

Dr. Philip Stieg, director of the neurosurgery department at the Weill-Cornell Medical College in New York, said the combined kidney failure and blood infection increase the chance that Sharon will contract pneumonia, a common killer of people his age and in his condition.

At the moment, Stieg said, Sharon is suffering "multi-system failure" and "it just becomes a snowball that just keeps getting bigger."

"It's obvious that they're doing everything to keep him alive. It's not clear why," Stieg said.

Sharon, Israel's most popular politician, had a small stroke in December and was put on blood thinners before suffering the severe brain hemorrhage in January. The Israeli leader underwent several, extensive brain surgeries to stop the bleeding, and many independent experts doubted he would recover.

The last surgery, in April, reattached a part of Sharon's skull that was removed to reduce pressure on his brain. The reattachment was described as a necessary step before transferring Sharon to the long-term care facility at Sheba hospital.

His stroke came after Sharon saw through his contentious plan to withdraw Israel from the Gaza Strip after 38 years. Just two months before, Sharon shook up the Israeli political map by bolting his hard-line Likud Party to form the centrist Kadima faction.

After the stroke, Sharon's successor as party leader, Ehud Olmert, led Kadima to victory in a March 28 vote and became prime minister.