Felty's syndrome

Overview

Felty's syndrome is a rare autoimmune disorder characterized by the triad of rheumatoid arthritis (RA), splenomegaly (enlarged spleen), and neutropenia (abnormally low levels of neutrophils, a type of white blood cell). It is considered a severe extra-articular manifestation of long-standing rheumatoid arthritis and typically occurs in patients who have had RA for more than 10 years. The condition increases susceptibility to infections and can lead to serious complications if left untreated.

Causes

The exact cause of Felty’s syndrome is not fully understood, but it is strongly associated with autoimmune mechanisms. Potential contributing factors include:

• Long-standing rheumatoid arthritis: Most cases develop in individuals with a history of severe, seropositive RA.

• Autoimmune attack: The body’s immune system mistakenly targets neutrophils and other components of the immune system.

• Genetic predisposition: A strong association with the HLA-DR4 gene suggests a genetic component to the syndrome.

Symptoms

Felty’s syndrome presents with a combination of features associated with rheumatoid arthritis and complications from neutropenia and splenomegaly. Common symptoms include:

• Joint pain and stiffness: Typical of rheumatoid arthritis, often affecting small joints symmetrically.

• Enlarged spleen (splenomegaly): May cause discomfort or fullness in the left upper abdomen.

• Recurrent infections: Especially skin and respiratory tract infections due to neutropenia.

• Fatigue and malaise: Common systemic symptoms in autoimmune diseases.

• Pale skin or easy bruising: If anemia or low platelet counts are also present.

Diagnosis

Diagnosis of Felty’s syndrome is based on clinical findings, history of rheumatoid arthritis, and laboratory tests. Key diagnostic steps include:

• Complete blood count (CBC): Shows neutropenia (low neutrophils) and may show anemia or thrombocytopenia.

• Rheumatoid factor (RF) and anti-CCP antibodies: Often positive in affected individuals.

• ESR and CRP: Elevated inflammatory markers typical of active rheumatoid arthritis.

• Abdominal imaging: Ultrasound or CT scan to confirm splenomegaly.

• Bone marrow biopsy: May be performed to rule out other causes of neutropenia, such as leukemia or aplastic anemia.

Treatment

Treatment of Felty’s syndrome focuses on controlling rheumatoid arthritis and managing neutropenia to reduce infection risk. Therapeutic options include:

• Disease-modifying antirheumatic drugs (DMARDs): Methotrexate is commonly used to control RA and may improve neutropenia.

• Biologic agents: Tumor necrosis factor (TNF) inhibitors, rituximab, or other biologics may be used in resistant cases.

• Granulocyte colony-stimulating factor (G-CSF): Used to increase neutrophil counts in severe neutropenia or during infections.

• Corticosteroids: Sometimes used to manage inflammation during flares.

• Splenectomy: Surgical removal of the spleen may be considered in patients with persistent neutropenia and recurrent infections despite other treatments.

• Antibiotics: Prompt treatment of infections and prophylactic antibiotics may be necessary in some cases.

Prognosis

With appropriate treatment, the prognosis for Felty’s syndrome can be favorable, especially when rheumatoid arthritis is well-controlled. However, untreated or poorly managed cases carry a higher risk of serious infections due to neutropenia, which can be life-threatening. Regular monitoring and a multidisciplinary approach are essential for managing both the rheumatologic and hematologic aspects of the disease.