What is the primary characteristic of Polyarteritis nodosa?

Polyarteritis nodosa is primarily characterized by inflammation of the small to medium-sized arteries. This condition is classified as a type of medium vessel vasculitis, which means it specifically affects arteries of medium caliber, leading to various complications depending on the organs supplied by the affected vessels.

The inflammation in polyarteritis nodosa can result in a range of systemic symptoms, including malaise, fever, and weight loss, as well as more specific complications like renal impairment or gastrointestinal issues, depending on the involved vascular territories.

While joint pain and skin rashes may occur with polyarteritis nodosa, they are not defining features of the disease. Instead, they can be symptoms associated with many forms of vasculitis or other conditions. The hallmark of this condition, however, is the pathology involving small to medium-sized arteries. Understanding this aspect is crucial for accurate diagnosis and treatment planning in clinical practice.