Infectious arthritis

Question 1

Why do you always want to perform arthrocentesis on someone with monoarticular arthritis

Answer 1

Crystals=gout
cultures=septic arthritis
blood=trauma
cellcount=inflammatory?

Question 2

What would you see in synovial fluid analysis of someone with OA?

Answer 2

Mildly elevated cell count (200-2000) otherwise normal?

Question 3

Synovial fluid in RA, SLE, gout?

Answer 3

HIGH cell count (2000-50,000)
Opaque fluid
High protein
Low glucose

Question 4

Synovial fluid in septic arthritis?

Answer 4

VERY HIGH cell count (75,000) with 90% polys
Opaque or pustular fluid
High protein
low glucose

Question 5

What are the most common causes of bacterial septic arthritis (species) in prosthetic joints?

Answer 5

Staph aureus (coag neg)
Alpha strep

Question 6

Which joints are most commonly involved in septic arthritis?

Answer 6

Knee, hip, ankle

Question 7

What factor worsen outcomes for septic arthritis?

Answer 7

Delay in diagnosis/treatment > 7 days
Prior arthritis
type of organism
elderly/immunocompromised

Ironically, IV drug users have a better prognosis

Question 8

How do you treat septic arthritis?

Answer 8

Drainage, debridement
Antibiotics
Physical therapy

Question 9

Should you remove the prosthesis or debride and keepit?

Answer 9

REMOVE IT! Unless it is an EARLY infection(i.e. no osteomyelitis) with a sensitive organism like strep AND removal not possible

However, if staph or gram negative infection, and >30 days post op or > 3 weeks of sx, remove

Question 10

What is the success rate of prosthesis removal?

Answer 10

80-90% with two-stages (removal then replacement)

compared with 70% with removal and replacement in one step

Question 11

Should we offer dental prophylaxis for patients after a prosthetic joint?

Answer 11

NO. bacteremia risk of daily living is much higher than dental work

Question 12

What infectious agent can cause dermatitis, tenosynovitis and migratory polyarthritis in an individual? OR septic arthritis?

Answer 12

Neisseria gonorrhea

Question 13

What infectious agent can cause arthritis and dermatitis syndrome?

Answer 13

N. Meningitidis. Occurs in chronic meningococcemia of carriers (no fever or meningitis)

Question 14

Slapped cheek + reticular rash + swollen joints = what pathogen?

Answer 14

Human parvovirus B 19

Question 15

What serious complication are you worried about in parvovirus B19?

Answer 15

aplastic crisis: B19 infects erythroblasts.

Question 16

What can you see in human parvovirus B19 infection in adults?

Answer 16

persistent arthritis without other symptoms. Looks just like RA.

Question 17

What do you see in fetuses with parvovirus B19?

Answer 17

hydrops fetalis

Question 18

What agent causes posterior cervical and postauricular node enlargement with fever, malaise, rash, and arthritis that looks like RA?

Answer 18

Rubella.

Question 19

Which mosquito–borne illnesses are emerging causes of arthritis?

Answer 19

dengue

Chikungunya

Question 20

Why would you want to check liver function tests in someone with urticarial rash and normal arthrocentesis but arthritis

Answer 20

Hepatitis can cause arthritis

Question 21

How would you confirm the diagnosis of disseminated Gonococcal infection?

Answer 21

1. Culture synovial fluid, skin, urethra/cervix and rectal.
2. Blood cultures
3. If purulent arthritis present, culture synovial fluid. Will be negative if pt has TAD form (tenosynovitis, arthralgia, and dermatitis)

Question 22

How does disseminated gonococcal infection present?

Answer 22

TRIAD: tenosynovitis, dermatitis, and polyarthralgia
OR
Prurulent arthritis without associated skin lesions

Question 23

What can present similarly to DIG?

Answer 23

Meningitis (usually severely ill), Hepatitis B (urticarial rash)

Question 24

What can present with inflammatory arthritis but no fever?

Answer 24

RA

Lupus

Question 25

If a pt has DGI, what else would you screen for?

Answer 25

HIV and syphilis and chlamydia