The long-term outlook for Osbourne's health, however, apparently is not nearly as dire as the news might suggest. Treatment for symptoms is available that could allow Osbourne to lead a full life with few complications, despite MS, some doctors say.
I was just angry and frustrated and kept thinking, 'Why now?' Osbourne, 26, said. I've got a family and that's what's supposed to be the most important thing.
The news came two weeks after his fiancée Lisa Stelly gave birth to their daughter Pearl Clementine. Osbourne said he noticed that he lost most of his vision in his right eye.
Multiple sclerosis is an autoimmune disease that attacks the central nervous system, which has no known cure. Its symptoms include difficulties in vision, loss of muscle control, balance and in severe cases, paralysis. It is usually diagnosed in people in their 20s, and 30s.
There are 200 new cases of MS diagnosed each week, according to the National Multiple Sclerosis Society, with 400,000 people in the U.S. living with the disease. It is more common in men than women.
Every nerve has insulation around it and MS attacks that insulation so that the electrical impulses from the brain to tips of fingers and toes don't work as well, said NBC's chief medical officer, Nancy Snyderman. So he's going to have to be really in tune with his body.
But the remainder of Osbourne's life may be devoid of many of the disease's worst symptoms.
The prognosis now is better than it's ever been, neurologist David Snyder, director of the Multiple Sclerosis Center at New York Hospital Queens, told NBC. We have treatments we just never had before.
Those treatments include medicines that slow down MS flare ups, though not entirely, for some patients.
Now somebody on medication, treated early, we're very hopefully we're interrupting the natural course of the disease, he said. Patients are leading full lives, with families, jobs and travel.
Many patients go on to live relatively full lives, often stifled only by a cane or some other precautionary measures.
I'm optimistic that future medications and treatments will allow them to live even better lives than people are now, Snyder said. Things are only going to get better.