[Bacterial arthritis with E. coli in an elderly patient].

Infectious arthritis is mostly caused by hematogenous spread of Gram-positive bacteria, which often infects a previously damaged joint. During the past 20 years there has been a notable increase in joint infections caused Gram-negative bacteria. They develop mostly in patients with systemic diseases, such as malignancy, cirrhosis or HIV infection, which cause an immune deficient state. We present an 84-year old man admitted because of fever and a diagnosis of pneumonia. During hospitalization he complained of pain in his right knee. On physical examination there was evidence of local inflammation. Infection with E. coli originating in the urinary tract was diagnosed, based on synovial fluid, blood and urine cultures. He was treated with antibiotics intravenously, the knee was surgically drained, and he was discharged 4 weeks after admission. There was no underlying systemic disease in this case that could have caused an immune deficient state, which could promote the Gram-negative joint infection. The case is presented to draw attention to the possibility of infectious arthritis in an elderly patient presenting with fever. In such cases the location of the infection may not be obvious if the infected joint is deeply located parts of bones such as those of the hip, shoulder, or vertebrae. In these cases the diagnosis may be overlooked or delayed and irreversible damage to the infected joint may result.