Dr. Marcelo Malakooti, chief medical officer at Lurie's, said in a statement that the hospital took its network offline "in an effort to protect the information of our patients, workforce and organization at large."
He said that the hospital is working with law enforcement, including the FBI, as well as with internal and external experts.
"As an academic medical center, our systems are highly complex, and these incidents can take time to resolve," Malakooti said.
"Throughout this period, all Lurie Children's locations have remained open accepting and caring for patients with as few disruptions as possible," Lurie Chief Clinical Officer and Chief Nursing Officer Brian Stahulak said during an afternoon press conference.
Not a Modern Healthcare subscriber? Sign up today.
Lurie established a dedicated call center to address patient families' and community providers' needs. The call center number is (800) 543-7362.
The call center is available Sundays from 8 a.m. to noon, Monday through Friday from 8 a.m. to 8 p.m. and Saturdays from 8 a.m. to 5 p.m.
It is meant for concerns such as nonurgent patient requests and care questions, information on scheduled patient appointments, and patient prescription refill requests, the update said. It also said the children's hospital is open and continues to take new patients and that anyone with a scheduled appointment should show up to that appointment.
This story first appeared in Crain's Chicago Business.