Bone and Joint Infections

Question 1

Is septic arthritis usually mono or poly - articular?

Answer 1

Monoarticular 90% of the time

Question 2

What are the signs/symptoms of acute septic arthritis?

Answer 2

Fever (>39), restricted ROM, swelling and inflammation

Question 3

What are the signs/symptoms of chronic septic arthritis?

Answer 3

Restricted ROM, swelling, inflammation, but no fever (not systemic)

Question 4

What type of bacteria are Streptococcus pyogenes, pneumoniae group B and Staphylococcus Aureus?

Answer 4

Gram positive cocci bacteria

Question 5

What type of bacteria is Neisseria Gonorrhoea?

Answer 5

Gram negative cocci

Question 6

What kind of bacteria is Haemophilus Infleunza?

Answer 6

Gram negative bacilli

Question 7

What is the most common cause of septic arthritis?

Answer 7

Staphylococcus aureus and Neisseria Gonorrhoea (16-50 year olds)

Question 8

What area is most commonly affected by septic arthritis?

Answer 8

The knee, but can occur at the hip, ankle and elbow

Question 9

What are the likely lab findings for someone with septic arthritis?

Answer 9

Elevated ESR/CRP, neutrophilia and synovial fluid may be purulent with reduced glucose levels

Question 10

How would infiltration of TB (mycobacterial infection) in a joint present on x-ray?

Answer 10

Joint space narrowing, effusions, erosions and cyst formation

Question 11

How may you distinguish between rheumatoid arthritis and septic arthritis?

Answer 11

RA is almost always bilateral, whereas septic arthritis is usually monoarticular

Question 12

How is septic arthritis treated?

Answer 12

Drainage and antibiotics

Question 13

What is reactive (Reiter’s) arthritis?

Answer 13

Reactive/post-infectious arthritis

Question 14

The presence of which HLA receptor is a risk factor for reactive arthritis?

Answer 14

HLA-B27

Question 15

What may cause reactive arthritis?

Answer 15

STI (chlamydia trachamatis), enteritis (salmonella campylobacter) or mzycobacter (TB)

Question 16

How does reactive arthritis usually present?

Answer 16

These are extra-articular symptoms

Question 17

What is osteomyelitis?

Answer 17

Infection of the bone (marrow) that mainly occurs due to haematogenous spread where there is thereafter a contiguous spread from an infected focus.

Question 18

What are risk factors for osteomyelitis?

Answer 18

o Impairment of immune surveillance e.g. malnutrition, extremes of age
o Impairment of local vascular supply e.g. diabetes mellitus, venous stasis, radiation fibrosis or sickle cell disease

Question 19

What is a Brodies’ abscess and when may it be seen?

Answer 19

Oval-shaped lesion that is surrounded by a thick, reactive hardening

Question 20

What kind of bacteria can flucloxacillin kill?

Answer 20

Gram positive bacteria e.g. staphylococcus and streptococcus

Question 21

What are the signs and symptoms of osteomyelitis?

Answer 21

Long bone: abrupt onset of fever, decreased limb movement and joint effusion
Chronic vertebral infection: insidious onset over 1-3 months

Non-specific pain presents

Question 22

What may the lab results show for osteomyelitis?

Answer 22

Elevated ESR and neutrophils,

Question 23

How is osteomyelitis treated?

Answer 23

Antibiotics, surgical debridement (remove dead bone) and bone reconstruct if necessary

Question 24

What are the risk factors for infection due to a prosthesis?

Answer 24

Prior surgery at site of prosthesis, RA, corticosteroid therapy, diabetes, obesity, malnutrition, old age

Question 25

How may infections from prostheses be avoided?

Answer 25

Eliminate infected foci (e.g. bad teeth), use peri-operative antibiotics, use laminar flow theatre ventilation, surgical team wear body suits, prophylaxis for subsequent interventions

Question 26

How may infections from prostheses be seen on x-rays?

Answer 26

There may be lucencies at the bone-cement interface, with changes in component position, cement fractures, periosteal reactions or gas in the joint

Question 27

How may infections from prostheses be treated?

Answer 27

Keep/replace prosthesis, resect the damage tissue or long-term antibiotics