Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (7 page)

   
SYSTEMIC AUTOIMMUNE DISEASES

FELTY SYNDROME

   Definition

   Felty syndrome is characterized by the triad of long-standing, aggressive rheumatoid arthritis (RA), neutropenia, and splenomegaly.

   It develops in a minority of patients with RA (<1%).

   Who Should Be Suspected?

   Patients typically present with general malaise, fatigue, loss of appetite, and unintentional weight loss. Some patients have recurrent infections, such as respiratory or skin infections, attributed to the neutropenia.

   The syndrome is more common in women >30 years of age and in patients with a family history of RA.

   Laboratory Findings

   Neutropenia (<2,000 granulocytes/μL) is required for diagnosis. WBC count is usually <2,500/μL.

   Elevated levels of rheumatoid factor (RF) and anti–cyclic citrullinated peptide (anti-CCP) antibodies (high titers).

   Antinuclear antibodies (ANAs), antihistone antibodies, and antineutrophil cytoplasmic antibodies (ANCAs) are found in more than two thirds of patients.

   Anti-glucose-6-phosphate isomerase antibody titer is elevated in the majority of patients.

   Anemia and thrombocytopenia may develop or be aggravated by splenomegaly (hypersplenism).