Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (15 page)

   The idiopathic disease most commonly occurs in individuals 40–60 years of age. Men are affected two to three times more than women.

   Laboratory Findings

Diagnosis is established by imaging studies.

   ESR and CRP are elevated in approximately one half to two thirds of patients.

   Anemia of chronic inflammation (normochromic, normocytic) is a frequent finding and can also be related to renal dysfunction.

   Leukocytosis, eosinophilia, hyperferritinemia, or hypergammaglobulinemia may be present in some patients.

   ANA test is positive in up to 60% of cases.

   Serum IgG4 levels are frequently elevated in patients with IgG4-related disease.

   Blood urea nitrogen (BUN) and creatinine can be elevated; levels are variable depending on the presence and size of urinary obstruction. Urine sediment is often normal.

Suggested Reading

Pipitone N, Vaglio A, Salvarani C. Retroperitoneal fibrosis.
Best Pract Res Clin Rheumatol.
2012;26(4):439–448.

Retroperitoneal Fibrosis

   Definition

   Rheumatoid arthritis (RA) is a chronic inflammatory arthritis characterized by progressive, symmetric joint swelling, tenderness, and destruction, leading in some cases to severe disability and premature mortality. The potential of synovitis to cause cartilage damage and bone erosion is characteristic for the disease. In addition to joints, RA may affect many other tissues and organs (e.g., lungs, pleura, pericardium, sclera), but the joints are usually most severely affected.

   Given the presence of autoantibodies, RA is considered an autoimmune disease, and it is the most common type of autoimmune arthritis. Autoimmunity and the overall systemic and articular inflammatory load drive the destructive progression of the disease.

   According to the 2010 ACR/EULAR criteria, classification of RA is based on the confirmed presence of synovitis in at least one joint, absence of an alternative diagnosis that better explains the synovitis, and achievement of a total score of 6 or greater (of a possible 10) from the individual scores in four domains: