Mod 3-5 Infectious Arthritis

Question 1

When does acute infectious (septic) arthritis develop?

Answer 1

When a joint’s synovial fluid becomes contaminated with a bacterium.

Question 2

What happens when the body’s defenses fight the infection in IA?

Answer 2

Triggers the production of chemicals that not only attack the bacteria but may also damage the joint surface.

Question 3

What happens after the bacteria is suppressed?

Answer 3

The breakdown of the joint may still continue.

Question 4

Who are high risk for developing infectious arthritis?

Answer 4

Those who receive the placement of a joint prosthesis or interarticular puncture.

Question 5

What is acute infectious arthritis?

Answer 5

A supperative (pus forming) and septic (infectious) form of arthritis.

Question 6

What is the etiology of acute infectious arthritis?

Answer 6

• Most usually caused by hematogenous spread of bacterial organism such as staph or strep from primary infection of the genitourinary tract or respiratory tract.
• Extension of osteomyelitis (bone infection) into adjacent joint
• Non-sterile techniques from iatrogenic (caused by medical exam) sources in joint examinations such as arthrogram, arthroscopy, joint surgery, etc…
• Long term illnesses such as renal failure, diabetes, TB and syphillis

Question 7

What joints may be involved in infectious arthritis?

Answer 7

Any joint but most common in large joints such as knee, hip, ankle, elbow, wrist and shoulder. As well as sternoclavicular articulation.

Question 8

How many joints are typically affected in each case of infectious arthritis?

Answer 8

Usually monarticular involvement (single joint involvement).

Question 9

What are the local clinical manifestations of infectious arthritis? And systemic clinical manifestations?

Answer 9

• Localized - redness, swelling, tenderness, and pain of the affected joint(s)
• Systemic - fever and chills

Question 10

What is virulence?

Answer 10

the severity or harmfulness of a disease or poison

Question 11

What determines the extent of joint damage and thus the radiographic manifestation of the process?

Answer 11

The virulence of the causative agent and chronicity of the infection.

Question 12

What is the earliest radiographic sign of acute arthritis?

Answer 12

Soft tissue swelling

Question 13

When does the earliest bone changes occur in infections arthritis?

Answer 13

8 - 10 days after the onset of symptoms

Question 14

What are the earliest changes in infectious arthritis?

Answer 14

Small focal erosions in the articular cortex of the affected joint and an increase in teh size of the joint space.

Question 15

What happens with severe, untreated affected joints with infectious arthritis?

Answer 15

Extensive destruction; including loss of the entire cortical outline.

Question 16

What may radiographs made during the healing phase show?

Answer 16

Fibrotic scarring that limits joint motion and infrequently bony ankylosis (calcified scarring).

Question 17

What is the affect of infectious arthritis on radiographic technique.

Answer 17

There is none.