infectious arthritis

Question 1

what bugs can cause episodic inflammation

Answer 1

syphilis, lyme, reactive arthritis (following enteric and chlamydial urethritis)

Question 2

what can cause acute polyarticular inflammation?

Answer 2

endocarditis, rheumatic fever, disseminated neisserial infection, and acute hepatitis B

Question 3

most common bugs in septic arthritis:
young adults:
adults:
older adults:

Answer 3

young adult: N. gonorrhea
adult: S. aureus
older adult: gram negative rods, penumococci, B-hemolytic strep (A and B)

Question 4

most common bug:
after surgical procedure:
after implantation of prosthetic joints or arthroscopy:
after human bites:

Answer 4

S. aureus
coagulase negative staph
anaerobic organisms

Question 5

what population has the highest incidence of infective arthritis?

Answer 5

RA patients (usually S. aureus) 
- chronically inflamed joints, steroids, frequent breakdown of rheumatoid nodules, vasculitic ulcers, and skin overlying deformed joints

Question 6

RFs for septic arthritis

Answer 6

diabetes, steroids, hemdialysis, malignancy, TNF inhibitors (etanercept, infliximab)

Question 7

common locations of septic arthritis in IV drug users

Answer 7

spine, sacroiliac joints, sternoclavicular joints

Question 8

common location among patients with RA

Answer 8

usually polyarticular, may resemble a flare of underlying disease

Question 9

empiric treatment for septic arthritis

Answer 9

1. 3rd generation cephalosporin (cefotaxime, ceftriaxone)
2. IV vanc if gram+ cocci on smear; if MRSA is unlikely, either oxacillin or nafcillin
3. aminoglycoside for pseudomonas coverage in pts at risk (IV drug users)

Question 10

people at greatest risk for gonococcal arthritis

Answer 10

young people
women during menses and pregnancy (disseminated gonococcal infection)
complement deficiencies

Question 11

signs of disseminated gonococcal infection

Answer 11

fever, chills, rash, and articular symptoms

rash: papules –> hemorrhagic pustules
articular: migratory arthritis and tenosynovitis of knees, hands, wrists, feet and ankles

Question 12

what causes the rash and articular findings in DGI?

Answer 12

immune complex deposition in tissues
(thus synovial fluid cultures consistently negative)
true gonococcal septic arthritis is less common than DGIand always follows it

Question 13

treatment of gonococcal arthritis

Answer 13

ceftriaxone (to cover possible penicillin-resistant organisms)
amoxicillin if sensitive

Question 14

initial signs of lyme arthritis

Answer 14

intermittent arthralgias and myalgias (notarthritis) within days/weeks of inoculation of spirochete

Question 15

what are the patterns of Lyme joint disease?

Answer 15

1. intermittent monoarthritis or oligoarthritis involving knee or other large joints
2. waxing and waning arthralgias
3. chronic inflammatory synovitis

Question 16

treatment of lyme arthritis

Answer 16

oral doxycycline
oral amoxicillin
parenteral ceftriaxone

Question 17

syphilitic arthritis

Answer 17

secondary syphilis may be ass w/ arthralgias, w/ symmetric arthritis of the knees and ankles, w/ sacroiliitis

Question 18

tuberculosis arthritis

Answer 18

unlike tuberculosis osteomyelitis (spine), arthritis involves large joints (hips, knees, ankles)

• progressive monoarticular swelling and pain over months/years
• occurs as part of disseminated primary infection or through late reactivation

Question 19

poncet’s disease

Answer 19

reactive symmetric form of polyarthritis that affects people with visceral or disseminated TB
- no TB is found in joints, symptoms resolve w/ anti-TB therapy

Question 20

diagnosis of TB arthritis

Answer 20

acid fast staining

culture (granulomatous inflammation)

Question 21

what bugs can cause subacute or chronic monoarthritis or olioarthritis/

Answer 21

myocbacterial or fungal infection

Question 22

common viruses in viral arthritis

Answer 22

mumps, rubella, hepatitis b, arthropod-borne diseases, HIV

Question 23

cause of reactive arthritis

Answer 23

nongonocococal urethritis (chlamydia), enteric infections (shigella, campylobacter, salmonella)

Question 24

signs of reactive arthritis

Answer 24

polyarthritis and sometimes urethritis, conjunctivitis, uveitis, oral ulcers, rash

Question 25

signs of acute rheumatic fever

Answer 25

migratory polyarthritis and fever (reactive arthritis is not migratory, lasts longer than 3 weeks and responds poorly to aspirin)

Question 26

typical treatment of prosthetic joint infections

Answer 26

surgery, antibiotics (usually oral rifampin and ciprofloxacin for staph infections)