Septic Arthritis Profoma

Question 1

Epidemiology of Septic Arthritis

Answer 1

Uncommon

Seen more often in children, young adults & elderly

Less common than osteomyelitis (infection of bone) in children

Question 2

Risk factors of Septic Arthritis

Answer 2

Age - over 80 years & children.

Co-morbid health conditions- particularly diabetes

Underling joint damage e.g. mainly RA

IV drug misuse

Prosthetic joint

Skin infection

Immunosuppression - by drugs or disease.

Question 3

Aetiology of Septic Arthritis

Answer 3

Most common causative pathogens:

• Staphylococcus aureus
• Streptococci
• Neisseria gonorrhoeae - most common in sexually active young adults- may affect multiple joints
• Chlamydia trachomatis
• Gram-negative bacilli- more common in older patients, neonates & immunosupressed patients.

Question 4

Pathogenesis of Septic Arthritis

Answer 4

1. The infection reaches the joint via:
   - Haematogenous spread (in blood) from skin or upper respiratory tract infections.
   - Direct spread from metaphysis
   - Penetrating trauma/surgery.
2. Bacterium settles in the synovium
3. Bacteria proliferates = causes an inflammatory response w/ leukocytes migrating into the joint.
4. Enzymes are produced, which breaks down the articulate cartilage w/in hours.

Question 5

Presentation of Septic Arthritis: clinical features & joint pattern

Answer 5

Clinical features:
- If patient has any of following symptoms, treat as septic arthritis until proven otherwise
1. Hot
2. Swollen
3. Acutely painful joint - intense pain - weight bearing not possible. Will not let you put joint through passive movements.
4. Restriction of movement
5. Joint effusion
6. High fever - usually systemically unwell (SAWTEM)

Joint pattern:
- May be a history of recent systemic infection e.g. as otitis media (middle ear infection), pneumonia, UTI, skin infection
- Common in knee & hip - shoulder, ankle, elbow & wrist also common.
- Can be present in any synovial joint.
- Monoarthritis (reactive arthritis is a polyarthritis)

NOTE- view images on notes!

Question 6

Investigation for Septic Arthritis

Answer 6

Joint aspiration & synovial fluid analysis:
- URGENT gram stain & acid-fast stain.
- URGENT culture - should grow something (unless the sceptic arthritis is caused by Lyme’s disease).
- Crystal examination - excludes gout or pseudo-gout
- High WBCs in synovial fluid (joint effusions)

• Normal- clear appearance
• Non-inflammatory arthritis- clear/ straw-coloured
• Inflammatory arthritis- cloudy yellow
• Septic arthritis- turbid

Blood tests
- Inflammatory markers- WCC, CRP & ESR= HIGH

Question 7

Management for Septic Arthritis: Medical & surgical

Answer 7

Medical:

1. IV antibiotic - wide spectrum - give straight after joint aspiration.
   - Flucloxacillin- 1st choice
   - Clindamycin
   - Vancomycin - for suspected MRSA infection
   - Cefotaxime
2. Relieve pain - oral or IV analgesics & ice packs.
3. Splint limb
4. Use results of gram stain & culture to narrow antibiotic used
5. Monitor using serial ESR & CRP.
6. Arrange physiotherapy

Surgical:

• Arthrotomy- creates an opening in the joint used for drainage.
• Arthroscopy - keyhole surgery to look in joints.
• Arthroplasty - resurfacing of bone or prosthesis. Done if infection is serious & the articular cartilage has been destroyed

Question 8

Prognosis for Septic Arthritis

Answer 8

If treated promptly, prognosis is good.

If missed or left untreated, can be fatal.