Several mornings a week, 84-year-old Stan Kraftsow and his wife, Carole, play tennis, sometimes against each other, sometimes as a high-energy doubles team.
Stan recognizes that anyone still on the court at his age is lucky, "but I'm even more fortunate than most," he says, calling to mind the childhood illness that made activities like tennis impossible - and threatened his life - eight decades ago.
When Stan was just 3 years old, his body mysteriously began to swell up. His concerned parents, Minnie and Ed, took him to doctor after doctor, but no one could determine what was wrong. For six months, Stan's swelling got progressively worse.
A diagnosis eluded doctor after doctor until the family arrived at CHOP, where nephrologist Mitchell Rubin finally found the answer.