Chronic periaortitis.

Chronic periaortitis commonly involves the infrarenal portion of the abdominal aorta. Idiopathic retroperitoneal fibrosis, inflammatory abdominal aortic aneurysm and perianeurysmal retroperitoneal fibrosis are its various clinical presentations. They present as a non-specific systemic inflammatory disorder and may lead to ureteric obstruction and consequent renal failure. An exaggerated inflammatory response to advanced atherosclerosis has been thought to be the main pathogenetic process. Autoimmunity has also been proposed as a contributing factor. Contrast-enhanced CT scanning is the diagnostic test of choice. Steroids and immunosuppressive agents are successfully used in the treatment of idiopathic retroperitoneal fibrosis and selected cases of inflammatory abdominal aortic aneurysm, and surgery is used in others. Early diagnosis is important in order to reduce morbidity from complications such as renal failure and mortality from aortic rupture.