Bone and Soft Tissue infection 2

Question 1

Route of infection of acute septic arthritis

Answer 1

• Direct invasion
• Eruption of bone abscess
• Haematogenous

Question 2

3 examples of direct invasion

Answer 2

• Penetrating wound (iatrogenic e.g. joint injection)
• Intra-articular surgery
• Arthroscopy

Question 3

Difference of septic arthritis and osteomyelitis

Answer 3

• Septic arthritis = Inside joint capsule

- Osteomyelitis = Outside joint capsule

Question 4

3 common organisms that cause septic arthritis

Answer 4

• Staph aureus
• Strep pyogenes
• E. coli

Question 5

Pathology of septic arthritis

Answer 5

• Acute synovitis with purulent joint effusion
• Articular cartilage attacked by bacterial toxin and cellular enzyme
• Complete destruction of the articular cartilage

Question 6

Outcome of septic arthritis

Answer 6

• Complete recovery
• Partial loss of articular cartilage + subsequent OA
• Fibrous or bony ankylosis (joint stiffness)

Question 7

Appearance of acute septic arthritis in a neonate

Answer 7

-Irritability
-Resistant to move
-Ill
Picture of septicaemia

Question 8

Appearance of acute septic arthritis in a child

Answer 8

• Acute pain a single large joint
• Reluctant to move joint
• Increased temp, + HR
• Tenderness

Question 9

Appearance of acute septic arthritis in an adult

Answer 9

• Often involves superficial joints (knee, ankle, hipe)

- Rare in a healthy adult

Question 10

Investigations for acute septic arthritis

Answer 10

• FBC, WBC, ESR, CRP, blood cultures
• X-ray
• Ultrasound
• Aspiration

Question 11

Most common cause of acute septic arthritis in adults

Answer 11

• Infected joint replacement

- Staph. aureus most common organism responsible

Question 12

DDx for acute septic arthritis

Answer 12

• Acute osteomyelitis
• Trauma
• Irritable joint
• Haemophilia
• Gout
• Rheumatic fever
• Gaucher’s disease

Question 13

Treatment of acute septic arthritis

Answer 13

• General supportive measures
• Antibiotics
• Surgical drainage + lavage (emergency, “never let the sun set on pus”,

Question 14

2 types of lavage

Answer 14

• Open

- Arthroscopic

Question 15

3 classifications of TB related to orthopaedics

Answer 15

• Extra-articular (epiphyseal/bones with haemodynamic marrow)
• Intra-articular (large joints)
• Vertebral body

Question 16

Clinical features of orthopaedic TB

Answer 16

• Insidious onset & general ill health
• Contact with TB
• Pain (esp. at night) + weight loss
• Low grade pyrexia
• Joint swelling
• Decreased ROM + ankylosis
• Deformity

Question 17

Pathology of TB

Answer 17

• Primary complex (in lung or gut)
• Secondary spread
• Tuberculous granuloma
• n.b. role of nutrition/other diseases (HIV/AIDS)

Question 18

Presentation of spinal TB

Answer 18

• Little pain

- Present with abscess or kyphosis

Question 19

How to diagnose TB

Answer 19

• Long Hx
• Involvement of a single joint
• Marked muscle wasting +marked thickening of synovium
• Periarticular osteoporosis

Question 20

TB investigations

Answer 20

• FBC, ESR
• Mantoux test
• Sputum culture
• X-ray
• Joint aspiration + biopsy

Question 21

What is show on a TB X-ray

Answer 21

• Soft tissue swelling
• Periarticular osteopenia
• Articular space narrowing

Question 22

DDx for TB

Answer 22

• Transient synovitis
• Monoarticular RA
• Haemorrhagic arthritis
• Pyogenic arthritis

Question 23

Treatment for TB

Answer 23

• Initially = Rifampicin, Isoniazid, Ethambutol for 8 weeks
• Then = Rifampicin + isoniazid for 6-12 months
• Rest + splintage
• Operative drainage rarely necessary