The next day Kara told her mother, a pediatrician, what had happened, and her mom insisted that she have an MRI. The radiologist found about 10 areas of ischemia (deficient supply of blood) throughout her brain and sent Kara back to the hospital to be admitted to the stroke ward. "I felt like a ticking time bomb," she says.
So, given her healthy habits, what put her at risk? "There were several factors, actually," says Kizer, including the history of stroke in her immediate family. And, unbeknownst to her, Kara and her mother shared a common heart problem, a patent foramen ovale (PFO)--a hole between the two upper chambers of the heart--which affects 27 percent of the population.
This hole is basically a portal that seems to allow clots to get to the brain. In fact, studies indicate that PFO is often found in young people with unexplained ischemic stroke. Because Kara was straining during sex at the time of her stroke, the flap between her heart chambers may have been open, causing blood to coagulate and giving a clot the chance to travel. The same could have happened when she was running, carrying a heavy box, or even having a particularly strenuous bowel movement. "I can't prove what caused Kara's stroke," says Kizer. "But circumstantially, the cause favors her PFO."
Yet there were also other risk factors--most significantly, those debilitating migraines with auras that she suffers once or twice a month. A 2007 study shows that women who have probable migraines with visual aura are 50 percent more at risk for stroke than other women. They are at even greater risk The younger the brain, the more elastic it is and the better able to compensate for losses. if they, like Kara, take birth control pills.
Most birth control pills are estrogen-based, and doctors won't prescribe them to someone with a medical and family history like Kara's. Instead, she took a progesterone-only pill. "These are thought to be safer, but they're still very controversial, and recent evidence suggests they don't necessarily have fewer risks," says Kizer.
Kara is lucky: She has no lasting impairment. She's off blood thinners--which led to volcanic, two-month-long menstrual periods--and now takes a daily aspirin as a preventive measure. She can still run, although she's no longer medically permitted to do half-marathons. "Anyone who sees me would never know I went through this," she says.
Nor would they know how often Kara wakes up in the middle of the night and says her name out loud to make sure her speech is not scrambled, or looks closely in the mirror to check that her smile isn't lopsided--all to prove to herself that it's not happening again.
"The worst part of having my stroke?" she says. "My fear that I will have another."
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