Septic Arthritis

Question 1

What is septic arthritis?

Answer 1

Infection of the joint

that damages articular cartilage and bone

Question 2

What is the infection of septic arthritis associated with?

Answer 2

Most commonly bacterial

Can be viral or fungal

Question 3

What are the causes of septic arthritis?

Answer 3

• Staphylococcus aureus or streptococci
• Direct injury to the joint
• Hematogenous spread
• Contiguous Osteomyelitis
• Rarely from arthrocentesis or arthroscopy

Question 4

What is involved with hematogenous spread?

Answer 4

Pts with indwelling catheters
Immunocompromised
UTIs

Question 5

What is important to know considering septic arthritis in IV drug users?

Answer 5

SC or SI joint

Pseudomonas aeruginosa

Question 6

What is observed in PE of septic arthritis?

Answer 6

Very painful, red, hot swollen joint
- Usually monoarticular
- Knee- more that 50% of cases
Decreased ROM
\+/- fever

Question 7

What imaging is used to diagnose septic arthritis?

Answer 7

Plain films

• Usually normal
• Soft tissue swelling; radiolucent lines if prosthetic joint infection

MRI
- Identify osteomyelitis

Bone Scan
- To evaluate for associated osteomyelitis

Question 8

What labs are used in diagnosing septic arthritis?

Answer 8

Synovial Fluid Analysis
CBC w/diff
ESR
CRP

Question 9

What will synovial fluid analysis in septic arthritis show?

Answer 9

WBCs > 50,000
Low glucose
High protein

Question 10

What is important to know about ESR and CRP in septic arthritis?

Answer 10

High sensitivity, low specificity

CRP more specific and rises faster

Question 11

What is the treatment of septic arthritis?

Answer 11

SURGERY
IV antibiotics
- Based on culture and sensitivity
- 4-6 weeks