<prompt> Which of the following is true about polyaeritis nodosa?It shows fibrinoid necrosis in large blood vesselsIt has ANCA positivityHBsAg is positive in 30 patientsAffected individuals have involvement of pulmonary circulation.  <response>: This condition is characterized by necrotizing immune complex inflammation of small- and medium-sized aeries. It is marked by the destruction of aerial media and internal elastic lamella, resulting in aneurysmal nodules. There is an association with hepatitis B viral infection in 30 of patients. Clinical manifestations often include fever, weight loss, malaise, abdominal pain, headache, myalgia, and hypeension. Polyaeritis nodosa is seen in the following sites: Kidneys, with immune complex vasculitis in the aerioles and glomeruli; renal lesions, and hypeension cause most deaths from polyaeritis nodosa. Coronary aeries, resulting in ischemic hea disease Musculoskeletal system, resulting in myalgia, ahralgia, or ahritis Gastrointestinal tract, manifesting as nausea, vomiting, or abdominal pain Central nervous system CNS or peripheral nervous system, the eye, or skin 