Which autoimmune disorder is characterized by a risk of organ failure due to vascular inflammation?

The autoimmune disorder characterized by a risk of organ failure due to vascular inflammation is polyarteritis nodosa. This condition primarily affects the medium-sized arteries, leading to inflammation of the blood vessel walls (vasculitis).

The inflammation in polyarteritis nodosa can cause a reduction in blood flow to various organs, resulting in damage and dysfunction. As organs become deprived of adequate blood supply, there's a significant risk for organ failure. The clinical manifestations can be diverse, depending on which organs are affected, including renal impairment, gastrointestinal ischemia, and neurological complications.

The other mentioned disorders do involve autoimmune processes but do not primarily present with the same vascular inflammation that leads directly to a high risk of organ failure. For example, rheumatoid arthritis primarily affects joints, polymyalgia rheumatica is characterized mainly by muscular pain and stiffness rather than organ risk, and scleroderma primarily involves skin and can cause vascular problems but does not specifically highlight the acute risk of organ failure through vasculitis in the same way as polyarteritis nodosa does.