Septic/Infective Arthritis

Question 1

Definition

Answer 1

Joint inflammation resulting from intra-articular infection. Also known as SEPTIC ARTHRITIS.

Question 2

Aetiology

Answer 2

• May be idiopathic

* In most cases there is systemic infection allowing for haematogenous spread

Question 3

Risk factors

Answer 3

o Recent orthopaedic procedures
o Osteomyelitis
o Diabetes
o Immunosuppression
o Alcoholism

Question 4

Causative organism

Answer 4

o Bacteria
• All ages
▪ Staphylococcus aureus
▪ TB

• < 4 yrs
▪ Streptococcus pneumoniae
▪ Streptococcus pyogenes
▪ Neisseria meningitidis
▪ Gram-negative rods

• 16-40 yrs
▪ Neisseria gonorrhoeae

o Viruses
• Rubella
• Mumps
• Hepatitis B
• Parvovirus B19

o Fungi
• Candida

Question 5

Epidemiology

Answer 5

Most common in CHILDREN and the ELDERLY

Question 6

Presenting symptoms

Answer 6

• Fever
• Excruciating joint pain
• Joint redness, swelling and loss of joint function
• Usually a monoarthropathy (usually affecting one large joint)
o NOTE: it may cause a polyarthropathy in the immunosuppressed
• Tuberculous arthritis develops more slowly and is more chronic

Question 7

Signs on physical examination

Answer 7

• Painful, hot, swollen
• Immobile joint
• Erythema
• Severe pain prevents passive movement
• Pyrexia
• Look for signs of aetiology

Question 8

Investigations (joint aspiration)

Answer 8

• Joint Aspiration (IMPORTANT)
o In infective arthritis, the aspirate will be grossly purulent
o Send synovial fluid for MC&S
• Microscopy - rule out crystal arthritis
o PCR may be used if a viral cause is suspected

Question 9

Investigations (other)

Answer 9

• Bloods
o FBC - high WCC, high neutrophils
o High CRP and ESR
o Blood cultures - MC&S
o Viral serology may be useful

• Plain Joint Radiographs
o Affected joint may look normal initially
o Can show signs of damage following the infection

• MRI Scan
o Useful for detecting osteomyelitis