Presidential spokesman Alfredo Scoccimarro said that Ms Fernández had suffered a “skull trauma” on August 12 that doctors discovered had worsened after they re-examined her on Saturday during a regular medical check-up.
As Ms Fernández occasionally suffers from migraines, doctors checked her skull, where they identified a “chronic” subdural haematoma, or bleeding between the brain and the skull.
Amado Boudou, the vice-president, is expected to assume presidential duties as he did in 2012 when Ms Fernández had surgery to remove her thyroid glands after she was incorrectly diagnosed with cancer. The former economy minister cut short an overseas trip over the weekend to return to Argentina.
Argentina faces midterm elections on October 27 in which polls indicate that Ms Fernández’s ruling coalition could lose control of Congress as Argentines have tired of her abrasive political style and handling of the economy.
“Ironically this could be an opportunity for Argentina as Boudou is someone who understands the economy well. He has common sense,” said Sergio Berensztein, a pollster at Poliarquía Consultores in Buenos Aires.
Mr Boudou, who has been dogged by corruption allegations after being investigated on charges of influence peddling, money laundering and illicit enrichment, was economy minister before being named vice-president in 2011.
If Ms Fernández follows doctors’ orders, she will be retiring from the political scene at a time when Argentina faces an array of mounting problems, from rising inflation estimated at 26 per cent, squabbles with neighbouring countries, and an ongoing legal battle with “holdout” creditors who refuse to accept the terms of debt restructurings after a major debt default in 2001, raising fears that another default is imminent.
Analysts say that a major defeat for her party in the midterms will make it all but impossible for Ms Fernández to secure the majority she needs to change the constitution that would allow her to run for a third presidential term in 2015 elections.
Ms Fernández, who last year missed a summit of Latin American and Spanish leaders on the advice of her doctors, succeeded her husband Néstor Kirchner, who died in 2010 of a heart attack. The death of her husband helped propel her to a massive victory in 2011 presidential elections, in which she won 54 per cent of the vote.