T&O: Septic Arthritis Flashcards
Outline the pathophysiology of Septic Arthritis.
Organisms may invade the joint by direct inoculation, contiguous spread from infected periarticular tissue, or via the bloodstream (the most common route)
Previously damaged joints (RA, SLE) are the most susceptible to infection = synovial membranes of these joints exhibit neovascularization and increased adhesion factors; both conditions increase the chance of bacteraemia
Large effusions, which can occur in infections of the hip joint, impair the blood supply and result in aseptic necrosis of bone
Outline the aetiology of Septic Arthritis?
Delayed wound healing is a major factor behind early prosthetic joint infection = S.aureus
N.gonorrhoeae
Viral = hepatitis B, parvovirus B19, and lymphocytic choriomeningitis viruses
Prosthetic joint infection - staph epidermis
Strep pneumonia
E.coli
What are the symptoms of Septic Arthritis?
Acute onset of joint pain
Reduced ROM active and passive
Low grade fever
Unable to weight bear
Swelling, erythema, warmth, tenderness
What are the important questions to ask when suspecting septic arthritis?
Whether the pain is superimposed on chronic pain
Previous Hx of joint disease/trauma, accidental or iatrogenic (infection complicates 0.4% of arthrocentesis)
Is the process monoarticular or polyarticular and which joints are involved?
Presence of extra-articular symptoms
Has the patient had vascular invasion = catheterizations or IV drug abuse
How would you investigate Septic Arthritis?
Joint aspiration = yellow-green due to elevated levels of nucleated cells
Gram stain = cultures and sensitivity
Microscopy for crystals
Bloods = CRP, FBC, ESR, urate
How would you manage Septic Arthritis?
Immobilisation of the joint
Antimicrobial therapy = 4-6 weeks, IV to start
Drainage of infected fluid = washout
What are the complications of Septic Arthritis?
Damage to the articular surface = OA
Osteomyelitis
