What is the disorder that 'knocked out' Ashton Kutcher's vision?

Ashton kutcher has revealed he was diagnosed with vasculitis, saying he was unsure if he would ever be able to see, hear or walk again.

In an episode of Running Wild with Bear Grylls: The Challenge, the 44-year-old actor Kutcher told Grylls "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 like all my equilibrium."

It took approximately a year to recover, he said, adding that considered himself "lucky to be alive."

Here's what you need to know about vasculitis.

Vasculitis is an autoimmune disorder that involves "inflammation of the blood vessels," according to the Mayo Clinic. The inflammation can lead to the walls of blood vessels thickening, blood flow being restricted and organ and tissue damage.

If a person has an autoimmune disorder, that means their immune system attacks their body instead of protecting it. Common ones include lupus, rheumatoid arthritis and Crohn's disease.

There are many kinds of vasculitis, which can affect one or several organs. It can be temporary or long lasting, depending on the type and the individual's health.

The symptoms can depend on the blood vessels that are affected. But many patients with vasculitis experience fevers, weight loss, fatigue, a rapid pulse, pain from skin ulcers and insufficient blood to the gastrointestinal tract. Other patients may have skin rashes, dark or bloody urine, cough or shortness of breath and more.

Some may also experience dizziness, ringing in the ears, hearing loss, double vision and temporary or permanent blindness.

The cause of different kinds of vasculitis is not fully known. But some types are linked to genetics, while others are caused by the immune system being triggered to attack blood vessel cells

Depending on the kind of vasculitis a person is experiencing, patients may be given corticosteroids or medications that suppress the immune system.

Some people with vasculitis may require surgery, including if arteries become blocked.

USA Today (TNS)