Doctors prepared to drill into Argentine President Cristina Fernandez's skull on Tuesday morning to siphon out blood that is pressuring her brain two months after she suffered an unexplained head injury.

Experts described the procedure as generally low risk and almost always having positive results, but the surgery on the 60-year-old leader worried many Argentines, who have struggled to imagine their country with anyone else at its center.

Fernandez was diagnosed with "chronic subdural hematoma", or fluid trapped between the skull and brain. This can happen when the tiny veins that connect the brain's surface with its outermost covering, or dura, tear and leak blood. As people age, it can happen with a head injury so mild they don't remember it.

In the president's case, doctors initially prescribed a month's rest, but decided surgery was required after she complained of numbness and weakness in her upper left arm on Sunday. A medical team rushed to the presidential residence, confirmed the new and worrying symptoms, and scheduled the surgery at the Fundacion Favaloro, one of Argentina's top cardiology hospitals.

While messages of sympathy poured in, the president's critics were questioning the secrecy that has surrounded her health recently. Her condition was announced in a three-paragraph statement on Saturday after she spent more than nine hours in the hospital, attributing the injury to a blow to her head on Aug 12. It gave no details on how the injury happened, and government officials declined to comment.

That would have been the day after primary elections showed a significant drop in support for her party's congressional candidates despite her intensive campaigning.

Fernandez, who followed her highly popular husband into the presidency, is the dominant figure in Argentine politics after nearly six years in office, and now she'll be off the campaign trail just three weeks before elections that could loosen her party's hold on the Congress.

As she returned to the hospital on Monday in preparation for surgery, Vice-President Amado Boudou made no mention of the planned operation. He said in a speech that top officials would run the country as a team "while she gets the rest she deserves".

"What Cristina wants is for us to maintain the administration, and to carry on this project that (her late husband) Nestor Kirchner began and that Cristina has continued," said Boudou, whose popularity has sunk amid ongoing corruption investigations.

Associated Press

(China Daily 10/09/2013 page12)