Felty syndrome is a rare, extra-articular manifestation of rheumatoid arthritis (RA), characterized 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 multifactorial 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.
History and exam
Key diagnostic 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 anticyclic citrullinated peptide (anti-CCP) antibodies
- ultrasound of abdomen
- CT scan of abdomen
- chest x-ray
- bone marrow biopsy
- virologic tests
- Large granular lymphocyte (LGL) syndrome
- Lymphoproliferative disorders
- Myeloproliferative disorders
- Guideline for vaccinations in patients with rheumatic and musculoskeletal diseases
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