Primary sternoclavicular septic arthritis in patients without predisposing risk factors

Septic arthritis (SA) of the sternoclavicular joint (SCJ) is an uncommon form of arthritis, generally described in patients with predisposing risk factors such as primary or secondary immunosuppressive disorders, systemic or localized infections and central venous catheters. More rarely the infection occurs in patients without these risk factors, thus rendering difficult an early diagnosis.

We report two cases of SA of the SCJ occurred in two patient, without known predisposing risk factors, hospitalized in our Internal Medicine Unit.

The clinical characteristics didn't significantly differ from clinical course of the disease occurring in patients with predisposing risk factors. Imaging techniques were useful to suspect diagnosis, but only fine-needle aspiration biopsy with culture of specimens leaded to identify the pathogen and its antibiotic sensitivity (in both patients Staphylococcus aureus). One patient was treated with surgical adequate curettage, drainage and intravenous methicillin, while the other one received only medical treatment with intravenous teicoplanin and ceftazidime. The outcome was uneventful with a complete recovery in both cases.

Even if SA of SCJ is uncommon in subjects without predisposing risk factors, the clinician must have a high index of suspicion to consider this disease in differential diagnosis of arthritis also in previously healthy subjects with negative or unsettling instrumental investigations. In fact, prompt diagnosis is essential to obtain a successful outcome, avoiding the prolongation of the hospitalization and the sequelae of a chronic infection.