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 RA patients.
Tends to occur in the fifth to seventh decades of life, typically in white patients 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.
The neutropenia in FS is defined as a neutrophil count <2 x 10⁹/L (<2000/microlitre) for >6 months.
History and exam
Key diagnostic factors
- presence of risk factors
- joint deformities
Other diagnostic factors
- rheumatoid nodules
- history of vasculitis
- frequent skin and respiratory tract infections
- rheumatoid arthritis (RA) >10 years
- family history of RA
- age >50 years
- white ethnicity
1st investigations to order
- peripheral blood smear
- serum erythrocyte sedimentation rate
- serum CRP
- serum rheumatoid factor
Investigations to consider
- serum antinuclear antibodies
- serum anti-cyclic citrullinated peptide (anti-CCP) antibodies
- ultrasound of abdomen
- CT scan of abdomen
- chest x-ray
- bone marrow biopsy
- virological tests
Dobrina N. Hull, MA, MRCP, PhD
Kingston upon Thames
DH declares that she has no competing interests.
Gerald Coakley, PhD, FRCP
Queen Elizabeth Hospital
GC is the author of one reference cited in this topic. GC has been reimbursed by Novartis to attend an educational conference in the UK.
Simon Bowman, PhD, FRCP
Consultant Rheumatologist and Honorary Senior Clinical Lecturer in Rheumatology
Selly Oak Hospital
SB declares that he has no competing interests.
Alice Klinkhoff, MD, FRCPC
Mary Pack Arthritis Program
Clinical Associate Professor
University of British Columbia
AK is the author of a study referenced in this topic.
Alan Bridges, MD
Professor and Vice Chair
Department of Medicine
University of Wisconsin Hospital
AB declares that he has no competing interests.
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