The vice president's office said Beau Biden was receiving treatment at Walter Reed Medical Center in Bethesda, Maryland. Officials did not specify what he was being treated for, though a source with knowledge of the Biden family called the situation "serious."
In 2013, Beau Biden was admitted to a Houston hospital that specializes in cancer treatment after feeling disoriented and weak while on vacation. He was later diagnosed with a brain lesion and underwent surgery.
In 2010, the younger Biden suffered what doctors said was a mild stroke. His speech and motor skills were not affected.
Biden, 46, was elected as Delaware's attorney general in 2006. He served in Iraq for one year as a captain with the Delaware Army National Guard, and acted as a prosecutor in the U.S. attorney's office in Philadelphia from 1997 to 2002