Septic arthritis Flashcards
What is septic arthritis?
Inflammation of a joint caused by bacterial infection
What joints can be affected by septic arthritis?
Any joint can be affected, but it’s most common in the knees (>50% cases) and hips
Why is septic arthritis a very important diagnosis?
Because it can destroy a joint in under 24 hours, and has a mortality rate of 11%
What is the pathophysiology of septic arthritis?
Septic arthritis is commonly caused by bacteria reaching the synovial membrane of the joint, either by bloodstream transport from an infection elsewhere, direct penetration into the joint following arthrocentesis, arthroscopy, or trauma, or from a surrounding infection in the bone or tissue
What are the risk factors for septic arthritis?
Pre-existing joint disease, especially RA
Diabetes mellitus
Immunosuppression
Chronic renal failure
Recent joint surgery
Prosthetic joint
IV drug abuse
Age >80 years
What are the common causative organisms in septic arthritis?
Staph. aureus
Streptococci
Neisseria gonococcus
Gram -ve bacilli
Describe the onset of symptoms in septic arthritis
The symptoms tend to develop quickly over a few hours or days
What are the symptoms of septic arthrtis?
Severe pain, swelling, redness, and heat in the affected joint
Pyrexia and rigors
Difficulty moving affected joint
Prostration
Vomiting
Hypotension
What investigations are done in septic arthritis?
Urgent joint aspiration for synovial fluid microscopy and culture
Plain radiographs(may be normal)
CRP (may be normal)
Blood cultures
What are the differential diagnoses of septic arthritis?
Gou
RA
Osteoarthritis
Drug-induced arthritis
Reactive arthritis
Viral arthritis
Infective endocarditis
Lyme disease
Vasculitis
How is septic arthritis treated?
Antibiotics
Corticosteroids
Joint drainage
Splinting
When should treatment with antibiotics be started in septic arthritis?
Empirical treatment should be started immediately, before the results of cultures are known
What bacteria should the antibiotic used in the empirical treatment of septic arthritis cover?
At least S. Aureus and Streptococcus spp.
Why should a microbiologist be consulted in the empirical treatment of septic arthritis?
To inform choice of therapy based on resistance patterns in local hospitals and the community
How are antibiotics administered in septic arthritis?
They are initially given intravenously (usually for 2-3 weeks) before being switched to oral (often for a further 2-3 weeks)
