Evaluation of neutropenia in an adult with rheumatoid arthritis

RA: rheumatoid arthritis; ANC: absolute neutrophil count; G-CSF: granulocyte colony-stimulating factor; RBC: red blood cell; CBC: complete blood count; TNF: tumor necrosis factor; IL-6: interleukin 6; JAK: Janus kinase; LGL: large granular lymphocyte; CT: computed tomography; BEN: benign ethnic neutropenia.
* Ideally cultures are obtained before antibiotics, but antibiotics should not be delayed while obtaining cultures or awaiting culture results.
¶ Severe anemia generally refers to hemoglobin <7 to 8 g/dL and/or hemodynamic compromise.
Δ Treatments for bleeding depend on the underlying cause and severity of bleeding. Refer to UpToDate for details.
◊ Splenomegaly, lymphadenopathy, and immature blood cells on the peripheral blood smear may be a sign of Felty syndrome, lymphoma, or LGL leukemia. Felty syndrome is a clinical diagnosis based on RA, splenomegaly, and neutropenia without another cause. LGL leukemia is a clonal disorder diagnosed by flow cytometry on peripheral blood or bone marrow. Both can be treated by immunosuppression, and G-CSF may be needed for neutropenia with infection. Lymphomas are clonal disorders with separate treatments based on the type and stage of lymphoma. Refer to UpToDate for details.
§ Benign ethnic neutropenia (BEN) is most common in individuals of African, Mediterranean, and Middle Eastern ancestry, but the diagnosis does not require a specific ancestry and cannot be inferred from ancestry.