Diffuse alveolar hemorrhage (DAH) is a life-threatening complication of systemic lupus erythematosus (SLE). Although infrequent, its mortality is very high. While there are no established therapeutic guidelines, DAH has been traditionally managed with high-dose intravenous (IV) corticosteroids, cyclophosphamide, and plasma exchange. The efficacy of alternative therapies such as rituximab has been described only in a few cases. Herein, we report a 25-year-old Hispanic man who presented with acute-onset SLE manifested by polyarthralgia, nephritis, seizures, pancytopenia, severe hypocomplementemia, and elevated anti-dsDNA antibodies. His disease course was complicated by DAH. His condition was refractory to high-dose intravenous (IV) methylprednisolone pulses, IV cyclophosphamide, and plasmapheresis. Given the lack of clinical response, he was started on IV rituximab 375 mg/m2 weekly for a total of four courses. He rapidly improved after the first two doses. Over the next seven months, he did not present recurrent pulmonary symptoms. Follow-up chest computed tomography did not show residual abnormalities. This case, together with other reports, suggests that rituximab is an effective therapeutic option for DAH in SLE.

FEDERAL PRACTITIONER • e41 mdedge.com/fedprac Background: Rheumatologic conditions share many symptoms with infectious processes. The immunosuppressive therapies used in rheumatology unfavorably impact any underlying infection. Nontuberculous mycobacteria (NTM) are difficult to grow in culture media and may affect the musculoskeletal system, developing manifestations that may imitate rheumatic inflammatory arthritis. For this reason, surgical debridement and biopsy culture are essential in cases where suspicion remains high. Case Presentation: We present the case of a patient with progressively worsening right-hand tenosynovitis who was evaluated for rheumatic conditions given initial negative synovial tissue biopsy cultures. He was finally diagnosed with Mycobacterium marinum infectious tenosynovitis after repeated surgical debridement. Conclusions: Our case reinforces the vital role of history gathering in establishing diagnoses and underscores the value of clinical suspicion in patients unresponsive to standard treatment for inflammatory arthritis. Tissue biopsy with culture for acid-fast bacilli is crucial for accurate diagnosis in NTM infection, which may imitate rheumatic inflammatory arthritis. Physicians should be keenly aware of this fastidious, indolent organism in the setting of persistent localized tenosynovitis.