It should have no long-term consequences if her doctors are saying she has suffered no neurological damage from it, he said.
Dr. Joseph Broderick, chairman of neurology at the University of Cincinnati College of Medicine, also called Clinton's problem "relatively uncommon" after a concussion.
He and Goldstein said the problem often is overdiagnosed. They said scans often show these large "draining pipes" on either side of the head are different sizes, which can mean blood has pooled or can be merely an anatomical difference.
"I'm sure she's got the best doctors in the world looking at her," and if they are saying she has no neurological damage, "I would think it would be a pretty optimistic long-term outcome," Broderick said.
A review article in the New England Journal of Medicine in 2005 describes the condition, which more often occurs in newborns or young people but can occur after a head injury. With modern treatment, more than 80 percent have a good neurologic outcome, the report says.
In the statement, Clinton's doctors said she "is making excellent progress and we are confident she will make a full recovery. She is in good spirits, engaging with her doctors, her family, and her staff."
Medical journal: http://dura.stanford.edu/Articles/Stam_NEJM05.pdf