Famed director, writer and actor Harold Ramis died early Monday morning of complications stemming from autoimmune inflammatory vasculitis at age 69. Just what is the autoimmune disease that contributed to the “Ghostbusters” writer’s death?

Vasculitis is an inflammation of the blood vessels, arteries, veins or capillaries, according to the Vasculitis Foundation. The condition causes a weakening and narrowing of the blood vessels, which eventually leads to blockages. The inflammation means that tissues and organs don’t get enough blood, causing organ and tissue damage that sometimes leads to death.

This is what happened to Ramis, whose health deteriorated in May 2010 to the point where he had trouble walking, his wife, Erica Mann Ramis, told the Chicago Tribune. He later recovered but had another setback from autoimmune inflammatory vasculitis in 2011. He died at 12:53 a.m. on Wednesday surrounded by family, she said.

Autoimmune inflammatory vasculitis is a rare condition. The prognosis for vasculitis depends on which form of the disease a sufferer has, which organs are affected, how quickly the condition deteriorates and the severity of the vasculitis, according to the Vasculitis Foundation.

“Treatment often works well if it’s started early," the foundation’s website says. "In some cases, vasculitis may go into remission. Sometimes vasculitis is chronic [ongoing] and never goes into remission. Long-term treatment with medicines often can control the signs and symptoms of chronic vasculitis. Rarely, vasculitis doesn’t respond well to treatment. This can lead to disability and even death. Much is still unknown about vasculitis. However, researchers continue to learn more about the condition and its various types, causes and treatments.”

There are a variety of signs and symptoms of vasculitis. Again, this depends on the type and severity of the condition. Some people notice few symptoms while others get very sick, according to the National Heart, Lung and Blood Institute.

Symptoms of vasculitis include fever, loss of appetite, fatigue, weight loss and general aches and pains. A sufferer may also notice purple or red bumps on the skin, bruises or hives. Joints may also ache and arthritis may develop in the joints.

The disease also manifests symptoms in the lungs, including shortness of breath or signs of pneumonia. Other areas of the body may be affected, including the gastrointestinal tract [ruptured intestines], the ears [middle ear infections], eyes [itchy, red, or burning eyes], the brain [headaches, changes in mental function, stroke-like symptoms], and the nerves [tingling, weakness, shooting pains in the arms and legs.]

Treatment for vasculitis includes corticosteroids to reduce blood vessel inflammation or other inflammation-reducing medications known as cytotoxic medicines, according to the NHLBI. Surgery may also be a part of treatment, especially if an aneurysm develops from vasculitis.