Glenohumeral Joint Sepsis Caused by Streptococcus mitis: A Case Report
Septic arthritis of the shoulder girdle remains relatively uncommon, with Staphylococcus aureus and β-hemolytic streptococci the typical offending organisms in adult patients. Rare cases of Streptococcus viridans, an oral bacterium with low virulence, have been reported in the setting of septic arthritis, mostly involving the knee joint or the sternoclavicular joint. In this article, we report a case of Streptococcus mitis infection of the glenohumeral joint that likely resulted from hematogenous spread after oral trauma in a patient with poor underlying dentition. Prompt diagnosis followed by arthroscopic irrigation and débridement of the glenohumeral joint resulted in a satisfactory clinical outcome.
The main routes for developing septic arthritis include direct inoculation secondary to penetrating trauma or hematologic spread.10 Coatsworth and colleagues11 reported on iatrogenic S mitis septic arthritis of a shoulder arthroplasty during ultrasonography-guided aspiration by a technician who was not wearing a mask. Our institutional policy is to perform joint aspiration under strictly sterile conditions, which were adhered to in the present case. We surmise our patient developed transient bacteremia from the loss of several teeth, particularly given his poor dentition. Yombi and colleagues5 documented 2 cases of septic arthritis caused by Streptococcus gordonii, a relative of S sanguinis. One involved a previously replaced knee, and the other a native knee joint. Other cases of S viridans group septic arthritis have involved the knee,6,7,12,13 the sternoclavicular joint,14-16 and the acromioclavicular joint.17S sanguinis6,7,12,15,16 and S gordonii5 have been implicated in most cases, and an unspeciated S viridans in others.13,14,17 Concomitant periodontal disease has been reported in most cases as well,6,7,12,15 including our patient’s case. In the English-language literature, we found no other reports of S mitis as the causative agent of acute septic glenohumeral joint arthritis from hematogenous spread.
There should be no delay in diagnosing septic arthritis, and infected material should be removed from the joint. In animal models, complete joint destruction occurred only 5 weeks after inoculation with Staphylococcus aureus.10 Garofalo and colleagues18 reported a trend toward improved functional outcomes after earlier operative treatment. The choice of open surgical drainage vs repeat needle aspiration seems to be of little consequence, as both have good long-term outcomes, but open surgical drainage seems to result in better long-term functional ROM.2,9 However, results of a recent study suggested surgical treatment is not always superior to medical treatment for septic arthritis in native joints.19 In some cases involving S viridans species, treatment consisted of a combination of IV antibiotics and onetime or repeat aspiration;6,12-15 treatment in the remaining cases was surgical débridement.5,7,16,17 Given that S viridans is associated with bacterial endocarditis, echocardiography is essential if this organism is to be identified. Medical management and antibiotic treatment should be initiated after consultation with medical and infectious disease specialists.19We have reported a case of septic shoulder caused by S mitis, a low-virulence organism seldom associated with joint infection. The patient’s infection likely resulted from hematogenous spread from the oral cavity (dentition was poor). Urgent aspiration of the joint and baseline infection laboratory tests are recommended. MRI of the shoulder may show an effusion. Urgent arthroscopic irrigation and débridement can yield good clinical outcomes.
Am J Orthop. 2016;45(6):E343-E346. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.
