a 57-year - old hiv - positive man was admitted to general internal medicine after presenting with acute - onset retrosternal chest pain accompanied by a 24 h history of fever .
apart from longstanding hiv infection , his medical history was significant for charcot - marie - tooth disease with a chronic ulcer on his right first toe , osteoporosis , kyphoscoliosis and depression .
two weeks before presentation , his cd4 count was 233 cells / mm with a viral load of < 40 copies / ml . the patient did not use intravenous ( iv ) drugs and was compliant with all of his medications including antiretroviral therapy ( darunavir , ritonavir , maraviroc and raltegravir ) , alendronate and buproprion . on examination ,
he was febrile ( 39.4c ) , with a blood pressure of 122/72 mmhg , heart rate of 100 beats / min , respiratory rate of 24 breaths / min and oxygen saturation of 100% on room air .
his neurological examination was normal and there were no rashes , active joints or stigmata of endocarditis .
the patient s chest pain was retrosternal , pleuritic , localized to the manubriosternal joint ( msj ) with some radiation to the scapula and was reproducible by palpation .
his foot ulcer showed no obvious signs of infection and there was no history of recent cellulitis .
complete blood count , electrolyte , creatinine and cardiac enzyme levels and a urinalysis were all normal .
his chest x - ray was normal and computed tomography ( ct ) ruled out pneumonia , fractures , pulmonary embolism and aortic dissection .
twelve hours after admission , two of two peripheral blood cultures were positive for gram - positive cocci in clusters .
the patient was started empirically on iv vancomycin , which was changed to cefazolin when the antibiotic sensitivities of the s aureus isolate became available 60 h after admission . despite resolution of the patient s
fever within 24 h of the initiation of antibiotics , he continued to experience severe central chest pain . by 48 h after admission , a new , tender mass was noted to have formed over the patient s msj .
inflammatory markers analyzed on the third day of admission were significantly elevated ( c - reactive protein 48 mg / l and erythrocyte sedimentation rate 120 mm / h ) .
although no obvious pathology of the msj was noted on the ct scan of the thorax , further imaging of this area was prompted by the patient s unresolving symptoms .
thoracic magnetic resonance imaging ( mri ) six days after admission revealed phlegmonous regions anterior and posterior to the msj , with lobulated enhancements that were not initially appreciated on ct ( figure 1 ) .
these findings were believed to be most consistent with septic arthritis of the msj . as a result
he was discharged home after eight days with a peripherally inserted central catheter . on discharge ,
the mass at the msj could not be palpated two weeks postdischarge and he remained well four months later .
acute chest pain is one of the most common reasons for presentation to the emergency department and , in the united states alone , accounts for approximately eight million visits per year ( 1 ) . determining the etiology of a patient s chest pain necessitates a broad differential diagnosis because more than one - half of these presentations are due to noncardiac causes ( 1 ) . to our knowledge , a total of 11 cases of msj septic arthritis
have been reported previously ; the present case is the first to be documented in an hiv - positive patient .
it is a secondary cartilaginous or symphysis joint , which has a lower risk of infection relative to synovial joints ( 2 ) .
owing to the rarity of this condition , the epidemiology and risk factors for septic arthritis of the msj are based on case series , summarized previously in a report by peng et al ( 2 ) , with two additional cases ( including the present case ) having been reported since ( 3 ) . to date
, the majority of patients with msj septic arthritis have been male ( 75% ) , with a mean age of presentation of 49 years ( median 46 years ; range 20 to 85 years ) ( 2,3 ) . a primary source of bacteremia outside of the msj ( eg
, idiopathic bacteremia or cellulitis ) was the most common risk factor and s aureus was isolated in 67% ( eight of 12 ) of cases ( 2,3 ) .
other reported risk factors include corticosteroid - induced immunosuppression , inflammatory joint disease and iv drug use ( 2 ) .
a more recent report argued that derangements in the bony architecture of the thorax , such as in patients with advanced scoliosis , may transmit to the msj and result in joint subluxation and subsequent susceptibility to septic arthritis ( 3 ) .
interestingly , our patient presented with significant kyphoscoliosis ; however , he had no previous history of subluxation or pain at the msj and imaging failed to demonstrate signs of anatomical abnormalities at the msj .
it is unclear to what extent the patient s hiv status contributed to his clinical presentation , although hiv infection is a known risk factor for septic arthritis in general ( 4 ) . while there are no known pathognomonic findings for msj septic arthritis , almost universally , central chest pain is accompanied by a tender and/or palpable mass at the msj ( 2,3 ) .
blood or synovial cultures were positive in 83% ( 10 of 12 ) of reported cases and provided sensitivities to guide antibiotic therapy ( 2,3 ) . of those
reported , 62% ( five of eight ) of blood cultures were positive , compared with 90% ( nine of 10 ) of msj cultures .
both blood and msj cultures were positive in 67% ( four of six ) of cases , when performed ( 2,3 ) .
imaging aided in the diagnosis of several cases , with mri suggested as the optimal modality owing to superior visualization of tissue and bone planes at the msj ( 5 ) .
our patient presented with all of the above signs / symptoms , with the exception of leukocytosis .
diagnostic confirmation was obtained based on positive blood cultures and the mri findings after a ct scan failed to detect any abnormalities . medical therapy with iv antibiotics tailored to culture and sensitivity results ( either blood or msj aspirate ) occurred in almost all cases ( 2,3 ) .
the duration of therapy was typically four to six weeks , consistent with the therapy for other similar forms of septic arthritis ( 2,3 ) .
in all previous cases successfully treated medically ( 33% ) , prompt diagnosis led to early initiation of antibiotics .
in the two culture - negative cases , both patients received surgical debridement in combination with broad - spectrum iv antibiotics ( 2,5 ) .
this highlights the importance of blood or synovial cultures in tailoring the antibiotic regimen given the prolonged duration of therapy .
the majority of reported cases ( 67% ) required surgical management in addition to antibiotics .
of these cases , three followed a delay in diagnosis while one occurred following failure of antibiotics ( 2,3 ) .
several surgical cases demonstrated evidence of msj destruction , highlighting the urgent need for appropriate treatment to prevent irreparable damage .
similar to the medically treated patients , all surgical cases received a six - week course of iv antibiotics tailored to culture sensitivity results , with good clinical outcomes ( 2,3 ) . in previous cases of septic arthritis , serial imaging
this may only be necessary if there is concern for failure of antibiotic therapy ( ongoing fevers , symptoms , worsening joint disruption ) .
our patient was managed with six weeks of iv cefazolin based on the sensitivities of the blood culture s aureus isolate . given his rapid clinical improvement with antibiotics , surgical debridement was not required .
we present a case of msj septic arthritis and the first in an hiv - positive patient .
diagnosis was made based on the patient s fever , chest pain , positive blood cultures and mri findings .
the patient was treated with six weeks of iv antibiotics with a good clinical outcome .
 the authors of this article report a case involving a 57-year - old man with longstanding hiv infection who presented with fever and acute chest pain , which was determined to be caused by an infection of the manubriosternal joint . 
 the course of treatment is described and a literature review summarizing the published cases of this rare infection is presented . 
CASE PRESENTATION
DISCUSSION
CONCLUSION