Case Presentation: A 44 year-old woman with a history of untreated rheumatoid arthritis (RA) initially presented to an outpatient gynecologist with several days of vaginal discharge and itching, which was diagnosed as bacterial vaginosis. Examination revealed a small excoriation on her labia. The following day, she experienced fevers, chills, headache, and malaise. She presented to the emergency room, where she had a temperature of 104.3F. Labs were remarkable for leukocytosis of 12.1 10^9/L (95.4% neutrophils, 8 bands). Blood cultures were drawn. Urinalysis, chest X-ray, and lumbar puncture were inconsistent with infection. The patient was diagnosed with likely influenza despite a negative nasal swab and discharged to home. That night she developed new excruciating left elbow pain. Concurrently, her blood cultures grew out gram-positive cocci in pairs and chains, and she was immediately recalled for admission to the hospital. The patient was febrile, tachycardic, and now hypotensive to 85/55. Her exam was notable for a clear oropharynx, no lymphadenopathy, no murmurs, mild bibasilar crackles, and a swollen, extremely tender left elbow with poor range of motion. A new set of labs revealed a lactate of 2.9 mmol/L and c-reactive protein (CRP) of 200 mg/L. A left elbow X-ray showed extensive joint erosion and joint space narrowing. Joint fluid analysis was significant for 288,000 WBC/mm3 (90% neutrophils) without crystals. The patient was diagnosed with severe sepsis from gram-positive bacteremia and septic arthritis presumably from hematogenous seeding. She was initially treated with fluid resuscitation, vancomycin and piperacillin-tazobactam, and a prompt joint washout by orthopedics on hospital day two. Subsequent echocardiography ruled out endocarditis. Blood and joint fluid cultures eventually speciated to Group A streptococcus (GAS), the most likely source thought to be skin flora that entered the blood through the patient’s labial excoriation. She was placed on penicillin G and clindamycin for antibiotic synergy. Within days she made a rapid recovery and was continued on intravenous antibiotics for a total of two weeks, followed by a prolonged oral course.

Discussion: Septic arthritis is a rheumatologic emergency that can lead to rapid joint destruction. Patients at greatest risk for contracting septic arthritis are those with abnormal joint architecture and pre-existing inflammatory joint disease such as RA, both exemplified by this case. The case also demonstrates a rare type of septic arthritis caused by GAS. Few such reports are described in the literature, but this one demonstrates several typical features, including portal of entry through a skin lesion, infection associated with severe systemic symptoms, and predilection for young women.

Conclusions: Septic arthritis, if left untreated, can destroy the affected joint and spread systemically. Early recognition even of rare causative bacteria such as GAS is crucial for rapid initiation of appropriate therapy.