Eunice Kennedy Shriver, 84, was also being treated for a recent stress fracture of the left hip, the statement issued Monday said. She was brought to the hospital on Saturday.
"Doctors anticipate a short hospital stay," the statement said.
Medical center spokesman Dan Page said he had no information beyond the prepared statement.
Eunice Kennedy Shriver has been an activist in the field of mental retardation and founded the Special Olympics for mentally disabled athletes. She is a sister of President John F. Kennedy and Sens. Robert and Edward Kennedy.