Polyarteritis nodosa (PAN), also known as panarteritis nodosa, periarteritis nodosa, Kussmaul disease, or Kussmaul-Maier disease, is a systemic necrotizing inflammation of blood vessels (vasculitis) affecting medium-sized muscular arteries, typically involving the arteries of the kidneys and other internal organs but generally sparing the lungs' circulation. Polyarteritis nodosa may present in infants. In polyarteritis nodosa, small aneurysms are strung like the beads of a rosary, therefore making "rosary sign" an important diagnostic feature of the vasculitis. PAN is associated with infection by the hepatitis B or hepatitis C virus.
Since hepatitis B virus infection is becoming less common, PAN has become increasingly rare. With treatment, five-year survival is 80%; without treatment, five-year survival is 13%. Death is often a consequence of kidney failure, myocardial infarction, or stroke.