Last updated: November 5, 2014
ICD-9 Code: 714.1.
Definition: Felty’s syndrome is classically defined as the triad of erosive deforming arthritis, splenomegaly, and leukopenia.
Risk Factors: Felty’s syndrome occurs almost exclusively among patients with severe, erosive, deforming RA who have high titers of RF in their serum. Furthermore, patients with Felty’s syndrome commonly have the HLA-DR4 and other HLA-DRβ1 alleles associated with disease severity in RA.
Etiology: The cause of Felty’s syndrome is unknown. Neutropenia may result from splenic sequestration of granulocytes. Defective granulocytic phagocytosis and chemotaxis may contribute to the susceptibility to infection.
Demographics: Felty’s syndrome primarily affects caucasians; it is rare, with a frequency that has significantly declined in the last 30 years.
Cardinal Findings: Although patients with Felty’s syndrome have evidence of deforming erosive RA, active synovitis may not be present at the time of diagnosis. Patients often display other extraarticular manifestations (e.g., rheumatoid nodules, Sjögren’s syndrome, rheumatoid vasculitis, episcleritis, pericarditis, or neuropathy) and may have evidence of weight loss, leg ulcers, recurrent infections, and splenomegaly. Splenomegaly may not be detected in all patients with extraarticular manifestations of RA and leukopenia. However, splenomegaly in Felty’s syndrome may be massive.
Diagnostic Tests: The leukopenia of Felty’s syndrome is typically a neutropenia (<2,000/mm3). Although lymphocyte numbers may be depressed in some patients, a number of patients with Felty’s syndrome have an increased number of large granular lymphocytes (LGL) in the circulation. Platelet counts are usually normal and thrombocytopenia is rare. As expected with severe RA, most patients are anemic. Despite the splenomegaly, leukopenia, and neutropenia, most patients with Felty’s syndrome do not develop serious infections. RF is uniformly present and may be accompanied by other autoantibodies (e.g., ANA, perinuclear ANCA [P-ANCA]).
Differential Diagnosis: Splenomegaly is uncommon in RA without evidence of Felty’s syndrome or neutropenia. Other causes of splenomegaly in patients with RA should be considered, including drug reactions, myeloproliferative diseases, lymphoma, amyloidosis, tuberculosis, and other chronic infections.
Therapy: Treatment of Felty’s syndrome parallels the treatment of severe RA. Many patients are treated with corticosteroids, DMARDs and/or biologic agents. There are no controlled studies, but numerous reports suggest that rituximab may be effective. Splenectomy may be considered in those with massive splenomegaly or recurrent infections. Patients with significant neutropenia and fever or documented infection may benefit from parenteral growth factor therapy (e.g., granulocyte colony-stimulating factor), although such agents may exacerbate the synovitis of RA.
Bowman SJ. Hematological manifestations of rheumatoid arthritis. Scand J Rheumatol 2002;31:251–259. PMID: 12455813