The Chicago Teachers Union announced Thursday that Vice President Jesse Sharkey will assume the duties of CTU President following Karen Lewis' emergency surgery Wednesday.
Sharkey, in a press conference Thursday afternoon, would not offer any information surrounding Lewis' condition, but said she has a "serious illness" and her surgery was successful.
"Out of respect to President Lewis’ wishes, the wishes of her family, and their privacy, we cannot provide details on her condition," the CTU said in a statement.
It remains unclear if the health concerns will interfere with Lewis' potential run for mayor.
Lewis was taken by ambulance to Northwestern Hospital Sunday night after attending a campaign event.
A source insists Lewis did not suffer a stroke, and while it's not clear what kind of emergency surgery she had, NBC 5 was told it was not heart surgery or related to her weight loss surgery.
“Karen Lewis is a passionate advocate for her beliefs and has always been willing to speak up for her view of what's best -- not only for the teachers that she represents, but also for issues critical to the future of our city," Chicago Mayor Rahm Emanuel said in a statement Thursday. "Along with all Chicagoans, we will keep Karen and her family in our thoughts and prayers, and we hope to see her on her feet very soon.”