ABSTRACT
Acute Bacterial Arthritis (Nongonococcal) This is most commonly due to hematogenous spread of bacteria. The hip and knee joints are commonly involved. Bacteria involved are gram-positive aerobic cocci (about 75% of cases): S aureus (most common) and β-hemolytic streptococci. Gram-negative aerobic bacilli also can cause infection (about 20% of cases); P aeruginosa is a common cause in injection drug users. Anaerobes, fungi, and mycobacteria are unusual. Clinical features include involvement usually of monarticular, large joints. Fever, pain, swelling, and restriction of motion are the most frequent signs and symptoms. The synovial fluid is usually turbid, and the leukocyte count generally exceeds 40 ×109/L (=75% polymorphonuclear neutrophils). The condition may overlap and be confused with other inflammatory arthropathies. Gram stain is 50% to 95% sensitive. Culture results are positive unless antibiotics have been used previously or the pathogen is unusual. Blood culture results are often positive. Radiographs are not helpful in routine cases because destructive changes have not had time to occur. Specific antimicrobial therapy is based on results of Gram stain, culture, and sensitivity testing. The duration of therapy is dependent on individual circumstances, such as the presence of complicating osteomyelitis. Usually, treatment is given for 2 to 4 weeks. Empiric therapy should include agents directed against S aureus and gram-negative bacilli. Drainage is essential. Percutaneous, arthroscopic, or open procedures are used. Hip, shoulder, and sternoclavicular joint involvement, development of loculations, and persistently positive culture results (not due to resistant organisms) are the usual indications for arthroscopy or open débridement.
