Infections of Bones and Joints

Question 1

What are the Newman Definition of Septic Arthritis

Answer 1

1 of 4 points must be met;

• Isolation of pathological agent from infected joint.
• In context of joint suspicious of sepsis, pathogen must be isolated from another source.
• Typical clinical features and turbid joint fluid in presence of antibiotic treatment.
• Post-mortum/pathological features sus of septic arthritis

Question 2

What is the typical presentation of Septic Arthritis

Answer 2

1/2 week history of a red, painful, restricted joint. Typically involved are large joints, most common are Knee, Hip and Lumbosacral spine

Question 3

What are predisposing conditions for septic arthritis?

Answer 3

Rheumatoid arthritis or osteoarthritis, joint prosthesis, intravenous drug abuse, alcoholism, diabetes, previous intra-articular corticosteroid injection and cutaneous ulcers.

Question 4

Name three causative organisms for septic arthritis

Answer 4

Staphylococcus aureus, Streptococcus pyogenes, Staphylcoccus epidermidis. Also don’t forget Neisseria gonorrhoeae.

Question 5

How can an infection be introduced into a joint?

Answer 5

Haematogenous spread or direct inoculation

Question 6

What are some of the investigations for septic arthritis?

Answer 6

Aspiration from an area of clean skin (looking at joint fluid), peripheral blood cultures, obtain relevant cultures, X-ray the joint.

Question 7

What is the management of septic arthritis?

Answer 7

Discuss with othopaedics for washout or if complicated discuss with infectious disease

Question 8

What is the classic triad for reactive arthritis

Answer 8

Conjunctivitis, urethritis and arthritis

Question 9

What are the dermatological manifestations of reactive arthritis

Answer 9

Keratoderma Blennorrhagicum, circinate balanitis, ulcerative vulvitis, nail changes and oral lesions

Question 10

What are the common causative organism for reactive arthritis

Answer 10

Chlamydia trachomatis and campylobacter

Question 11

How can reactive arthritis be treated?

Answer 11

Full dose NAIDS with gastric protection and treatment of precipitating factors (eg, chlamydia)

Question 12

What is osteomyelitis

Answer 12

Inflammation of the bone and bone marrow usually caused by pyogenic bacteria, and rarely by mycobacteria or fungi.

Question 13

How do bones become infected?

Answer 13

Haematogenous spread, local spread, compound fracture and foreign body

Question 14

Name some examples of foreign bodies that can cause bone infections

Answer 14

Trauma, Sharpnel/GSW, ortho implant, nail through trainer (because of pseudomonas through the trainer)

Question 15

What are the consequences of septic arthritis

Answer 15

With delayed treatment it can lead to irreversible joint damage, and the case-fatality is approx 11-50%.

Question 16

What makes you predisposed to osteomyelitis

Answer 16

Sick cell anaemia (salmonella), Travel/milk (brucella), prosthesis (S. epidermis), children under the age of 5 (H. influenzae), UTI (E.coli)

Question 17

Describe features of haematogenous spread of infection to bones

Answer 17

Usually asymptomatic, skin sepsis may be present and organisms can settle in growing metaphysis near the growth plate.

Question 18

What are the main organisms that cause osteomyelitis

Answer 18

Staphylococcus Aureus (over 80%) and S.pyogenes (5%). TB can also cause it and gram neg bac

Question 19

What are the signs and symptoms of osteomyelitis

Answer 19

Painful, swollen site, Fever, reduced movement, paraplegia (loss of sensation and movement in lower limbs)

Question 20

What are the preliminary investigations for osteomyelitis

Answer 20

If patient has fever, their WBC and their ESR and CRP.

Question 21

What sort of imaging can you use for osteomyelitis and what will you see?

Answer 21

You can use X-rays but MRI and bone scans are more sensitive. You will see periosteal elevation, focal osteopenia, cortical thinning and scalloping.

Question 22

What are further investigations of osteomyelitis

Answer 22

Blood culture, Xray, MRI/CT/Bone scan and sample pus. Must take at least three samples in surgery.

Question 23

What are some primary risk factors for prosthetic joint infection

Answer 23

• Rheumatoid arthritis
• Diabetes Mellitus
• Poor nutrition
• Obesity

Question 24

What is the main causative organism in prosthetic joint infections and what is the best imaging technique for diagnosis.

Answer 24

Staphylococcus Aureus. Best imaging is Tc bone scan