Secretary of State Hillary Clinton was admitted to a New York City hospital on Sunday after doctors discovered that a blood clot had formed, the State Department said in a statement.

Philippe Reines, a deputy assistant secretary, said in the statement that the clot stems from a concussion Clinton sustained several weeks ago.

Reines said that Clinton, 65, is being treated with anticoagulants at NewYork-Presbyterian Hospital in Manhattan. She will be monitored there for the next 48 hours,

A deep vein thrombosis, known as a DVT, or a dural venous sinus thrombosis, could be two types of blood clots treated with anticoagulants, said Dr. Alex Valadka, a spokesman for the American Association of Neurological Surgeons. A blood clot could be dangerous if it breaks free and lodges in a vital organ, such as the heart.