Septic arthritis

Question 1

What is septic arthritis?

Answer 1

Infection of the joint

Question 2

What are the main causative organisms for septic arthritis - state who they commonly affect

Answer 2

Staphylococcus aureus - most common in adults
Streptococcus species
Salmonella - sickle cell disease
Gonorrhoea - sexually active

Question 3

Describe the pathogenesis of septic arthritis

Answer 3

Bacteria will seed the joint from a bacteraemia, direct inoculation or spread from adjacent osteomyelitis

Question 4

Describe staph aureus on gram stain

Answer 4

Purple cocci - Gram stain positive

Question 5

What are the complications of septic arthritis

Answer 5

Osteoarthritis

Osteomyelitis

Question 6

What are the common symptoms of septic arthritis

Answer 6

Acutely swollen, hot, very painful joint with pain on movement and a reduced range of movement
Unable to weight bear

Question 7

What is found on examination of septic arthritis

Answer 7

Red, hot, swollen joint
Reduced range of movement and rigid joint
Effusion
Pyrexia in 60%

Question 8

What investigations are needed in septic arthritis

Answer 8

FBC, CRP, ESR, urate levels, 2 blood cultures
Joint aspiration and synovial fluid analysis - do before giving antibiotics
Plain radiograph
USS may be used to assist aspiration

Question 9

What is the management of septic arthritis

Answer 9

IV antibiotics for 2 followed by 4 weeks oral antibiotics
Irrigation and debridement (washout)
Prosthetic joints will require washout and revision

Question 10

What are the risk factors for septic arthritis

Answer 10

DM and immunosuppression
Age >80
Joint problems - RA
Prosthetic joints 
Chronic renal failure 
IVDU