Mueller was brought to intensive care on Tuesday night stricken with a 105-degree fever following a procedure on her wisdom teeth earlier this week.
"Brooke is in the hospital ICU related to the surgery for her impacted wisdom tooth," Yale Galanter, her lawyer, told Access. "They are trying to get the infection and fever under control. The infection has spread."
Her health woes come as she prepares to face husband Charlie Sheen in court in Aspen, Colorado, at a hearing that was previously delayed due to her wisdom tooth surgery.
The "Two and a Half Men" actor – who is under court orders not to communicate with Mueller – has been spotted at the hospital.
For Mueller's part, Galanter told Access that she hopes to scale back the protective order issued following Sheen's Christmas Day arrest on domestic violence charges.
"Mueller wants to be able to communicate with her husband and hopes they can go back together as a family with their 9-month-old twins, Bob and Max," Galanter said.
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