Mystery surrounds Secretary of State Hillary Clinton's medical crisis.
Clinton's State Department Spokesman Phillipe Reines said, "In the course of a follow-up exam, Secretary Clinton's doctors discovered a blood clot had formed, stemming from the concussion she sustained several weeks ago."
The spokesman refused to say where the blood clot has formed—in her leg or her brain. Adding to the mystery, he referred to "other issues" that are affecting her health.
Dr. Jennifer Ashton told INSIDE EDITION, "After the initial clot is treated and dissolved, the patient remains on blood-thinning medication for a period of six months. For someone such as Secretary Clinton, who does a lot of travel, and long travel at that, there would be a discussion with her physicians about giving her preventative injections of blood-thinning medication before long trips."
Clinton, who is 65, was last seen in public on December 7th in Northern Ireland. Two days later, she cancelled a trip to North Africa and the Middle East, with her spokesperson saying she was "under the weather."
Only later was it revealed that Clinton had suffered a severe concussion after fainting. She had been dehydrated with a severe stomach virus.
Clinton has a history of blood clots. In 1998, when she was first lady, she was hospitalized for a clot in her leg following a rigorous travel schedule.
Earlier this month, Barbara Walters named Hillary Clinton one of 2012's most intriguing people. And she bragged about her strong constitution.
Walters asked, "Is your age a concern to you?"
"It really isn't. I am, thankfully, knock on wood, not only healthy, but have incredible stamina and energy," said Clinton.