Felty Syndrome

Associated with rheumatoid arthritis

Felty syndrome is a potentially serious condition that is associated with rheumatoid arthritis. Research in the United States has shown that Felty syndrome affects 1-3% of all individuals with rheumatoid arthritis, and rheumatoid arthritis occurs in about 1% of the general population. The true number of individuals with Felty syndrome is not known because many who have the disorder have no symptoms. In those diagnosed with the disorder, women outnumber men 3 to 1. Research has suggested that Felty syndrome is most likely an autoimmune disorder.

Risk factors for Felty syndrome include long-standing rheumatoid arthritis that is severe and high positive titer for rheumatoid factor.

Symptoms
There are three main symptoms of Felty syndrome:

• long-standing rheumatoid arthritis, usually severe
• enlarged spleen (splenomegaly)
• low white blood cell count (white blood cells fight infection)

Because of the low number of white blood cells, Felty syndrome can lead to life-threatening infections, most commonly in the lungs or the skin. Therefore, an infection could be a sign of Felty syndrome. Individuals with Felty syndrome often have other symptoms due to their rheumatoid arthritis, such as joint deformities, Sjogren syndrome, or small blood vessel inflammation (vasculitis).

Diagnosis
A bacterial infection of the skin or lungs in a person with rheumatoid arthritis might suggest a diagnosis of Felty syndrome. A white blood cell count can determine if the level of granulocytes is low. Most individuals (98%) with Felty syndrome have high titers of rheumatoid factor, and many (67%) have antinuclear antibodies (ANA) in their blood. Erythrocyte sedimentation rate (ESR) and serum immunoglobulin levels are also elevated in individuals with Felty syndrome.

Treatment
The best treatment for Felty syndrome is to control the underlying rheumatoid arthritis. Immunosuppressive drugs such as methotrexate (Rheumatrex) may be used. Other drugs used to treat rheumatoid arthritis, such as etanercept (Enbrel) and infliximab (Remicade), may be used, but these drugs have not been studied extensively as treatments for Felty syndrome.

Information for this article was taken from:
Keating, R. M. (2004). Felty syndrome. eMedicine, accessed at http://www.emedicine.com/med/topic782.htm