Illinois Senator Kirk Hospitalized Following Stroke CHICAGO - Mark Kirk, a U.S. Senator from Illinois who won President Barack Obama's former seat in 2010, was admitted to a Chicago-area hospital over the weekend after suffering a major stroke. The stroke, which caused swelling in the right side of his brain, will likely affect his ability to use his left arm and possibly his left leg. It may also cause some facial paralysis. The news came as a shock to many in Washington and Illinois because Mr. Kirk, 52, was a long-time intelligence officer in the naval reserve and apparently in good physical condition. "Fortunately the stroke was not on the left side of his brain, which would affect his ability to speak, understand and think," said Richard Fessler, a neurosurgeon at Northwest Memorial Hospital downtown, where Kirk is in intensive care. We are very hopeful that when he gets through all of his recovery, all of those functions will be intact. At a press conference on Monday, Mr. Fessler said Mr. Kirk checked himself into a nearby hospital on Saturday after experiencing dizziness and headache. There, doctors discovered a blockage in his carotid artery, which caused the stroke. On Sunday, he was transferred to Northwest Memorial and rushed into surgery after he started to "deteriorate neurologically" because of swelling in his brain, according to Mr. Fessler, who performed the 3-hour surgery, removing a 4-inch by 8-inch section of Mr. Kirk's skull to relieve the pressure. "Senator Kirk is young, is in very good shape and very healthy," Mr. Fessler added, calling the surgery successful. All those things are in his favor. Before winning the senate seat in 2010, Mr. Kirk was a five term congressman with centrist leanings in a state that has, historically, elected moderate Republicans to statewide office. The race in 2010 against Alexi Giannoulias, a Democratic challenger who had served as state treasurer, had been grueling and hard fought. The seat itself had been the center of controversy - it was the job that that former Gov. Rod R. Blagojevich had been accused of trying to sell or trade to the highest bidder after Mr. Obama stepped down in 2008 to go to the White House. Many of Mr. Kirk's colleagues at the state capital and in Washington have already released statements of support, including Illinois" other senator, Richard Durbin, who offered to help with his duties during the recovery period. For now, doctors say it's too soon to tell how long that will take. Dr. Fessler said Mr. Kirk may not regain full use of his left arm, but he is hopeful for a full mental recover in the coming weeks. "We are very encouraged by the prognosis," said Mr. Kirk's family in a statement read by a spokesperson for the senator. Mark has always had great courage and resilience, and we are confident that the fighter in him will prevail.