The reality star, perhaps best known as one of the alleged White House party crashers, is the subject of Cirque du Salahi, written by Diane Dimond.
Salahi, 44, tells PEOPLE why she kept her diagnosis of the potentially crippling nervous system disorder quiet for 17 years. "No one wants to be seen as sickly," she explains. "And I didn't want to be pitied."
But despite her struggles, Salahi says being positive keeps her going: "The only way I can deal with it is to smile and act like I can get through it."
For more on how Salahi has coped with MS, pick up the new issue of PEOPLE, on newsstands Friday