Final answer:
Infectious arthritis, also known as septic arthritis, is an inflammation of joint tissues caused by bacterial pathogens. It can affect any joint and is characterized by joint pain, swelling, and limited motion. Diagnosis involves analysis of synovial fluid, and treatment usually includes appropriate antimicrobial drugs.
Step-by-step explanation:
Infectious arthritis, also known as septic arthritis, is an inflammation of joint tissues caused by bacterial pathogens. It can be either acute or chronic and is characterized by joint pain, swelling, and limited motion of the affected joint. In older adults, septic arthritis can occur due to underlying medical conditions, such as immunosuppression, and can affect any joint.
In order to diagnose infectious arthritis, a small quantity of synovial fluid from the affected joint is taken and analyzed through direct microscopic evaluation, culture, antimicrobial susceptibility testing, and polymerase chain reaction (PCR). Treatment for infectious arthritis usually involves administration of appropriate antimicrobial drugs based on the identified pathogen. Prognosis can be poor, with permanent joint damage and mortality rates ranging from 5% to 20%.
Common causative bacteria for septic arthritis include Staphylococcus aureus, which is the most common cause in adults and young children, and Neisseria gonorrhoeae, which is an important cause in sexually active individuals.