Bone and Soft Tissue infection 2 Flashcards
Route of infection of acute septic arthritis
- Direct invasion
- Eruption of bone abscess
- Haematogenous
3 examples of direct invasion
- Penetrating wound (iatrogenic e.g. joint injection)
- Intra-articular surgery
- Arthroscopy
Difference of septic arthritis and osteomyelitis
- Septic arthritis = Inside joint capsule
- Osteomyelitis = Outside joint capsule
3 common organisms that cause septic arthritis
- Staph aureus
- Strep pyogenes
- E. coli
Pathology of septic arthritis
- Acute synovitis with purulent joint effusion
- Articular cartilage attacked by bacterial toxin and cellular enzyme
- Complete destruction of the articular cartilage
Outcome of septic arthritis
- Complete recovery
- Partial loss of articular cartilage + subsequent OA
- Fibrous or bony ankylosis (joint stiffness)
Appearance of acute septic arthritis in a neonate
-Irritability
-Resistant to move
-Ill
Picture of septicaemia
Appearance of acute septic arthritis in a child
- Acute pain a single large joint
- Reluctant to move joint
- Increased temp, + HR
- Tenderness
Appearance of acute septic arthritis in an adult
- Often involves superficial joints (knee, ankle, hipe)
- Rare in a healthy adult
Investigations for acute septic arthritis
- FBC, WBC, ESR, CRP, blood cultures
- X-ray
- Ultrasound
- Aspiration
Most common cause of acute septic arthritis in adults
- Infected joint replacement
- Staph. aureus most common organism responsible
DDx for acute septic arthritis
- Acute osteomyelitis
- Trauma
- Irritable joint
- Haemophilia
- Gout
- Rheumatic fever
- Gaucher’s disease
Treatment of acute septic arthritis
- General supportive measures
- Antibiotics
- Surgical drainage + lavage (emergency, “never let the sun set on pus”,
2 types of lavage
- Open
- Arthroscopic
3 classifications of TB related to orthopaedics
- Extra-articular (epiphyseal/bones with haemodynamic marrow)
- Intra-articular (large joints)
- Vertebral body
