Ch 3 - Rheumatology: Infectious Arthritides

Question 1

What is the clinical presentation of septic arthritis?

Answer 1

– Rapid onset of moderate to severe Monoarticular, joint pain, erythema, and decreased ROM
– Leukocytosis
– Fevers/chills, sepsis

Question 2

What is the most common joint involved in septic arthritis?

Answer 2

Knee

Question 3

What are risk factors for septic arthritis?

Answer 3

– Age
– Prosthetic joints/foreign body
– Comorbidities such as anemia, chronic diseases, hemophilia

Question 4

What is the most common organism causing septic arthritis in adults?

Answer 4

Neisseria gonorrhea

Question 5

What is the most common organism causing septic arthritis in children?

Answer 5

Staphylococcus aureus

Question 6

What are causes of septic arthritis in children?

Answer 6

Otitis

Infected IV lines

Question 7

What are causes of septic arthritis in Neonates and > 2 years old?

Answer 7

S. aureus

Group B strep

Question 8

What are causes of septic arthritis in 6 months to 2 years old?

Answer 8

Haemophilus influenza

Question 9

What is the most common organism causing septic arthritis in RA?

Answer 9

S. aureus

Question 10

What are lab findings of septic arthritis?

Answer 10

Elevated WBC, ESR, CRP

Question 11

What are early radiographic findings of septic arthritis?

Answer 11

Soft-tissue swelling

Question 12

What are late radiographic findings of septic arthritis?

Answer 12

Joint space narrowing
Erosions
Gas formation (Escherichia coli, Clostridium perfringens)

Question 13

Describe normal joint fluid analysis.

Answer 13

Viscosity: high
Color: colorless
Clarity: translucent
WBC: <200
PMN%: <25
Culture: negative
Mucin clot: good
Glucose: = to blood

Question 14

Describe non-inflammatory joint fluid analysis.

Answer 14

Viscosity: high
Color: straw
Clarity: translucent
WBC: <5,000
PMN%: <25
Culture: negative
Mucin clot: good
Glucose: = to blood

Question 15

Describe inflammatory joint fluid analysis.

Answer 15

Viscosity: low
Color: yellow
Clarity: translucent/ opaque
WBC: 1,000-75,000
PMN%: >50
Culture: negative
Mucin clot: fair
Glucose: <50mg/dL lower than blood glucose

Question 16

Describe septic joint fluid analysis.

Answer 16

Viscosity: variable
Color: turbid-yellow
Clarity: opaque
WBC: >100,000
PMN%: >85
Culture: positive
Mucin clot: poor
Glucose: >50mg/dL lower than blood glucose

Question 17

What are viral causes of septic arthritis?

Answer 17

Rubella

Infectious hepatitis

Question 18

What are fungus causes of septic arthritis?

Answer 18

Seen in immunocompromised adults

Question 19

What is Pott’s disease?

Answer 19

TB spondylitis

Question 20

What is affected in Pott’s disease?

Answer 20

Lower thoracic/upper lumbar region

Question 21

What causes kyphotic deformities in Pott’s disease?

Answer 21

Anterior vertebral body preferentially affected

Question 22

What is affected in TB arthritis?

Answer 22

Hips and knees

Question 23

What is Phemister’s triad?

Answer 23

Radiographic findings of TB arthritis
– Juxta-articular osteoporosis
– Marginal erosions
– Joint space narrowing

Question 24

What causes Lyme disease?

Answer 24

Tick-borne infection from Borrelia burgdorferi

Question 25

What is the clinical presentation of Lyme disease?

Answer 25

– Erythema migrans (“bull’s eye” rash)
– Cardiac, neurologic, articular manifestations
– Bite>rash> systemic disease> neurologic involvement
– Intermittent migratory episodes of polyarthritis

Question 26

What joint does Lyme disease commonly affect?

Answer 26

Knee

Question 27

How is Lyme disease diagnosed?

Answer 27

– Synovial fluid—inflammatory

– ELISA, Western blot analysis

Question 28

What is the treatment of Lyme disease?

Answer 28

Adults: doxycycline
Children: amoxicillin