Clinical Case: Knee Pain Flashcards Preview

Skin MS: Week 4 > Clinical Case: Knee Pain > Flashcards

Flashcards in Clinical Case: Knee Pain Deck (19):
1

Reactive arthritis

Acute asymmetric arthritis following urethritis (chlamydia) or gastroenteritis
6 weeks after infection
Joints of legs (knees)
May also get conjunctivitis + urethritis = Reiter's syndrome

2

Septic arthritis (monoarticular) - two organisms

Staph aureus - most common overall, patients usually have pre-existing joint problem or IV drug users
Neisseria gonorrhoeae - most common organism under age 30

Joint aspiration to know

3

Dx of GC arthritis

H/P
Lab - WBC high (above 10,000)
blood cultures frequently positive (not always)
joint aspiration shows WBC over 100,000 (not specific)
Gram stain and culture PRIMARY

4

tx of GC arthritis

3rd gen cephalosporin
oral macrolide abs (azithromycin) also indicated for presumptive tx of chlamydia
prognosis usually good w/ rapid resolution of sxs and signs

5

Septic arthritis commonly caused by

Staph aureus

(or Neisseria gonorrhoeae)

6

Urethritis, conjunctivitis and monoarthritis is called

Reiters syndrome

7

Gout

Uric acid crystals precipitate in joint
Very acute onset
Most common site in great toe
Low grade fever

8

Pseudogout

Looks same as gout
Cause: calcium pyrophosphate crystal deposition
Can involve same joints (feet, knee, wrist, ankle) + Shoulder and hips

9

acute monoarticular arthritis definition

acute joint inflammation that occurs days or less before seeking attention

10

acute monoarticular arthritis differential

gout, pseudogout, reactive arthritis, septic arthritis

11

Gout dx

Dx: joint aspiration, polarized light demonstrates negatively birefringent crystals

12

pseudogout dx

Dx: Joint aspiration, positive birefringent crystals

13

Reiter's syndome

Reactive arthritis + conjunctivitis +urethritis

14

GC arthritis - two musculoskeletal syndromes form disseminated GC

Arthritis-dermatitis syndrome - arthralgias, skin lesions, inflammation of tendons
Localized septic arthritis - septic arthritis and bacteremia rarely found at same time (knee most common)

15

Neisseria gonorrhoeae

bacteria - gram (-) - diplococci - oxidase (+) - only glucose oxidizer

16

Neisseria gonorrhoeae virulence factors

specialized pilli - allows attachment to mucosal surface, antigenic variation to evade host defenses, prevents phagocytosis
Endotoxic
Capsule
IgA protease

17

Media used for isolated N. gonorrhoeae

Thayer-Martin

18

Most common cause of septic arthritis in sexually active people

N. gonorrhoeae

19

NG pathogenesis

attach via pili to mucosal cells of urethra and vagina - evades mucosal IgA Ab via IgA protease. Endocytosed by cells. Kills cilliated cells. --> inflammatory response leading to urethritis and cervicitis.