- Acute inflammatory condition of a joint
- Usually results from bacterial infection
- Untreated it will lead to destruction of the articular cartilage
- 50% cases occur in children less than 3 years of age
- In infants less than one year old the hip is the commonest joint involved
- In older children the knee is the commonest joint affected
- 10% of patients have multiple joints involved
Microbiology
- Infecting organism depends on age
|
Children |
Adults |
| < 3 years old |
> 3 years old |
< 50 years old |
> 50 years old |
| H. influenzae |
Staph aureus |
Staph aureus |
Staph aureus |
| Staph aureus |
H. influenzae |
Neisseria gonorrhoea |
Gram-negative |
| Coliforms |
|
|
Streptococci |
- Organism can enter joint via a number of routes
- Penetrating wound
- From epiphysis or metaphysis
- Haematogenous spread
- Provoke an acute inflammatory response
- Large number of neutrophils accumulate in joint
- Release proteolytic enzymes that break down the articular cartilage
- Results in joint effusion and reduced synovial blood supply
- Complications of septic arthritis include
- Avascular necrosis of epiphysis
- Joint subluxation / dislocation
- Growth disturbance
- Secondary osteoarthritis
- Persistent or recurrent infection
Clinical features
- Exact presentation depends on age
- Children are usually systemically unwell
- Present with pain in the affected joint
- All movements of the joint are painful
- Reluctant to stand on weight-bearing joints
- Affected joint is usually swollen, red and warm
- Hip involvement results in flexion and external rotation
- In adults septic arthritis is usually associated with immunosuppression
Investigations
- Key investigation is culture of a joint aspirate
- Should be performed prior to the administration of antibiotics
- Other appropriate investigations should include
- Inflammatory markers
- Plain x-rays
- Bone scan
Differential diagnosis
- Irritable hip
- Perthe's disease
- Osteomyelitis
- Gout
- Pseudogout
Management
- Antibiotics should be started after joint aspiration
- Empirical therapy should be commenced based on likely organisms
- Adjusted depending antibiotic sensitivity
- Antibiotics should be continued for 6 weeks
Surgery
- Involves joint drainage and lavage
- May be performed arthroscopically
- Early joint mobilisation should be encouraged
Bibliography
Garcia De la Torre I. Advances in the management of septic arthritis. Rheum Dis Clin North Am
2003; 29: 61-75.
Shirtliff M E, Mader J T. Acute septic arthritis. Clin Microbiol Rev 2002;
15: 527-544. |