|

Felty’s Syndrome

Last updated:

Overview

Felty’s syndrome (FS) is a complication of rheumatoid arthritis (RA) characterised by a triad of:

Its exact pathophysiology is unclear. Inflammation may lead to splenomegaly. Splenomegaly may contribute to increased recycling of neutrophils leading to neutropenia.

Epidemiology

  • Only seen in patients with seropositive RA
  • Incidence is decreasing due to the use of more effective RA treatment
  • FS affects around 1% of patients with RA

Risk Factors

  • Longstanding RA (>10 years)
  • Increased RA severity with extra-articular manifestations
  • Family history of RA
  • >50 years
  • Caucasian ethnicity

Presentation

Patients present with RA and may not have obvious additional features due to RA. Some features include:

  • Increased susceptibility to infection due to neutropenia
  • Splenomegaly – may manifest as left upper quadrant pain
    • Hepatomegaly may also be seen
  • RA and its severe features (e.g. joint deformity)

Differential Diagnoses

Lymphoma

  • There is usually associated lymphadenopathy
  • There may be a history of B-symptoms (e.g. fever, weight loss, night sweats)
  • A lymph node biopsy may be necessary

Systemic lupus erythematosus (SLE)

  • Rheumatoid nodules are not present and SLE arthritis is generally non-deforming
  • Associated features of SLE are present (e.g. skin rash, mouth ulcers, alopecia, and Raynaud’s syndrome)

Sarcoidosis

  • Arthritis in sarcoidosis is generally non-deforming
  • Associated features of sarcoidosis are present (e.g. lymphadenopathy, erythema nodosum, parotid gland enlargement, bilateral hilar lymphadenopathy on a chest x-ray)

Diagnosis

There is no specific test to diagnose FS.

  • Full blood count (FBC):
    • Shows neutropenia
    • May show thrombocytopenia (may occur due to splenomegaly) 
  • Peripheral blood smear:
    • Helps to rule out other haematological causes of neutropenia
    • Shows neutropenia without any pathological cell types
  • Liver function tests:
    • Generally measured as splenomegaly can lead to hepatomegaly
    • Transaminases and alkaline phosphatase may be elevated
  • Bone marrow biopsy:
    • This is required to confirm Felty’s syndrome and exclude other causes of neutropenia including haematological malignancy
  • Ultrasound scan to assess splenomegaly:
    • If this is inconclusive, a CT can be done

Management

Overview

Treatment involves controlling the underlying RA and treating neutropenia. Options may include:

  • DMARDs such as methotrexate, sulfasalazine, or leflunomide
  • Colony-stimulating factors – for neutropenia
  • Splenectomy – generally a last-resort option

Complications

  • Severe/recurrent infections
  • Complications due to increased sequestration of blood cells:
    • Anaemia – due to increased red blood cell sequestration
    • Thrombocytopenia and easy bleeding – due to increased platelet sequestration
  • Portal hypertension and variceal bleeding
  • Non-Hodgkin lymphoma

Prognosis

  • Patients with FS have a poorer prognosis than those with uncomplicated RA
  • Serious infection is the main cause of death

Author