Spontaneous septic arthritis in a patient without trauma, coinfection, or immunosuppression.

Septic arthritis is a rare infection, most often affecting the knee and hip [1]. Infections are often secondary to joint repair or replacement surgery, systemic infection, or intravenous recreational drug use [1,2].Diabetes, rheumatoid arthritis, hepatic dysfunction, and immunosuppression are common risk factors [1,2]. Although septic arthritis can occur spontaneously, such occurrences are rare. We report a case of a previously healthy 54-year-old woman with no known risk factors presenting to a freestanding emergency department with 5 days of shoulder pain.