Polyarteritis nodosa

In hematology and rheumatology, polyarteritis nodosa is a vasculitis and "a form of necrotizing non-granulomatous inflammation occurring primarily in medium-sized arteries, often with microaneurysms. It is characterized by muscle, joint, and abdominal pain resulting from arterial infarction and scarring in affected organs."

Polyarteritis nodosa usually spares the lungs. While it commonly involves renal arteries, it spares glomeruli and does not cause glomerulonephritis. If lungs are involved, the patient may have vasculitis associated with antineutrophil cytoplasmic antibodies (Wegener's granulomatosis, microscopic polyangiitis, or Churg-Strauss syndrome). If glomerulonephritis is present, the patient may have microscopic polyangiitis.