DALLAS — Blood clots don’t tend to grab headlines.

Mostare caused by trauma or recent surgery, said Dr. James Kohn, a vascular surgeon on the medical staff at Doctors Hospital at White Rock Lake in Dallas.

So if you’ve had neither surgery nor trauma, you might assume you’re safe. Blood clots, which made news recently when former Secretary of State Hillary Clinton was hospitalized, also occur in otherwise healthy people who have none of the traditional risks. When they do, they can be life-threatening.

Doctors say that problems for Clinton, 65, were related to dehydration and a fall, but not all cases are so understandable.

“Some form, and we never have a reason,” said Dr. Robin Novakovic, assistant professor in radiology, neurology and neurotherapeutics at the University of Texas Southwestern Medical Center in Dallas.

Such was true for Dallas area residents Mary Campise and Mike Mignardi. Both are runners; both take phenomenal care of themselves. Both had potentially fatal blood clots — technically known as deep vein thrombosis, or DVT — within the past two years.

Although the two are now running again, their experiences have made Campise and Mignardi especially aware of what can go wrong and turned them into crusaders.

“I’ve become one of those people who, whenever I have a chance, warn others about the dangers,” said  Campise, assistant dean of students at Ursuline Academy.

Last year, a few weeks shy of her 48th birthday, she was healthy, “running, biking, doing everything,” she says. She had never smoked, never used oral contraceptives — two common risk factors for blood clots.