Ashton Kutcher details vasculitis symptoms: 'Lucky to be alive'

Ashton Kutcher has recently overcome some life-changing health issues.

In a recent episode of National Geographic’s “Running Wild with Bear Grylls: The Challenge,” the “That ’70s Show” actor spoke about his experience with a rare disease that hindered his ability to see, hear and walk.

“Two years ago, I had this weird, super rare form of vasculitis that knocked out my vision. It knocked out my hearing. It knocked out all my equilibrium,” he explained in a sneak preview of the episode.

Vasculitis is a condition in which blood vessels become inflamed, which can lead to restricted blood flow and organ and tissue damage, according to Mayo Clinic. There are several types of vasculitis, but overall symptoms include fever, headache, fatigue, weight loss, as well as general aches and pains. Loss of hearing and sight can also be signs of vasculitis.

“You don’t really appreciate it until it’s gone,” Kutcher remarked in the preview, referring to his loss of sight. “Until you go, ‘I don’t know if I’m ever going to be able to see again, I don’t know if I’m ever going to be able to hear again, I don’t know if I’m ever going to be able to walk again.’”

According to Mayo Clinic, vasculitis can also impact a patient's mobility, as some types can cause weakness or numbness in the hands and feet, and the soles of the feet can become swollen or hardened.

Reflecting on this period of health uncertainty, Kutcher shared how he changed his mindset to get through it.

“The minute you start seeing your obstacles as things that are made for you, to give you what you need, then life starts to get fun, right?” he explained to Grylls. “You start surfing on top of your problems instead of living underneath them.”

The exact cause of vasculitis isn't known, the Mayo Clinic noted. Some are due to a patient's genes, whereas others are triggered by the immune system and immune disorders, like rheumatoid arthritis and lupus.

Kutcher’s episode of “Running Wild with Bear Grylls: The Challenge” will airs Monday on National Geographic.