Felty's syndrome

Felty's syndrome is a rare, extra-articular manifestation of rheumatoid arthritis (RA), characterised by persistent, idiopathic neutropenia and, in some cases, splenomegaly. Estimated to occur in <1% of people with RA.

Tends to occur in the fifth to seventh decades of life, typically in white people who have had long-standing seropositive, erosive RA.

A clinical diagnosis with no specific diagnostic test; other causes of neutropenia should be excluded.

Cause of neutropenia is multi-factorial and is thought to result from an imbalance between neutrophil production in the bone marrow and increased destruction in the peripheral blood.

Goal of therapy is to raise the neutrophil count and prevent recurrent infections, while controlling systemic rheumatoid disease activity.

Felty's syndrome (FS) is a rare, extra-articular manifestation of rheumatoid arthritis. It is characterised by persistent, idiopathic neutropenia and frequently (>90% patients) by splenomegaly.[1]Felty AR. Chronic arthritis in the adult associated with splenomegaly and leucopenia. Bull Johns Hopkins Hosp. 1924;35:16-20.[2]Campion G, Maddison PJ, Goulding N, et al. The Felty syndrome: a case-matched study of clinical manifestations and outcome, serologic features, and immunogenetic associations. Medicine (Baltimore). 1990;69:69-80. http://www.ncbi.nlm.nih.gov/pubmed/1969604?tool=bestpractice.com

The neutropenia in FS is defined as a neutrophil count <2 x 10⁹/L (<2000/microlitre) for >6 months.[2]Campion G, Maddison PJ, Goulding N, et al. The Felty syndrome: a case-matched study of clinical manifestations and outcome, serologic features, and immunogenetic associations. Medicine (Baltimore). 1990;69:69-80. http://www.ncbi.nlm.nih.gov/pubmed/1969604?tool=bestpractice.com