2.1 Mmi Exam3: Musculoskeletal 1

Front 1

In an established bone infection (osteomylitis), the local inflammatory response and pus (under pressure) cause impaired blood circulation leading to avascular necrosis of the affected part; thus a _ is formed

Back 1

sequestrum

Front 2

Most common cause of acute osteomyelitis AND septic arthritis

Back 2

Staphylococus aureus

(^only coagulase + staph)

Front 3

MC Osteomyelitis infection affecting Sickle cell pts?

HLA DRB1 or HLA DQB1 in sickle cell makes pts more susceptible?

Back 3

Salmonella

HLA DQB1 = increased susceptibility

(HLA DRB1 has more resistance)

Front 4

What is the most common microbe causing osteomyelitis following a puncture wound?

Back 4

Pseudomonas aerginosa

Front 5

2nd MC cause of acute osteomyelitis

Back 5

Strep pneumoniae

Front 6

What is the 2nd most common microbe causing osteomyelitis & septic arthritis in newborns?

Back 6

Group B strep

Front 7

2nd MC cause of acute osteomyelitis after trauma or surgery?

Back 7

Group A strep (strep pyrogenes)

Front 8

___________ is characterized by;

-soft tissue & bone injury & infection

-discharging sinus*

-concurrent erosion & subperiosteal deposition of bone*

-bone pain, fever

Back 8

chronic osteomyelitis

Front 9

A 10-year-old boy who recently migrated from Sri Lanka with his family presents with a bump at the T12-L1 region. He also complaints of severe pain while picking something from the ground. The boy has history of cough and low grade fever for several months. Which of the following is likely involved in this case?

Back 9

M. tuberculosis

Front 10

The most common osteoarticular manifestations resulting from hematogenous spread from pulmonary M. Tuberculosis is _____________

Back 10

Pott's disease= Vertebral osteomyelitis

Front 11

A 55 year-old man with a titanium knee from previous arthroplasty presents with pain, redness and swelling around the prosthetic joint following lower GI endoscopy. The organism involved in this case very likely is

Back 11

Enterococcus species

Front 12

Most common causative organism for osteomyelitis?

Back 12

staphylococcus

staph aureus (coag +)
coag (-): staph epidermidis

(followed by aerobic gram - & peptostreptococcus sp)

Front 13

Puncture wound by a dirty nail?

Back 13

Clostridium

Front 14

Bite wound involves what pathogens?

Back 14

Eikenella or Kingella

Front 15

Evidence of osteomyelitis as indicated by _ and _

Back 15

erosion of bone and subperiosteal bone deposition

Front 16

Diagnostic steps for osteomyelitis

Back 16

1. blood culture- identify responsible microbe

2. x-ray (if blood culture is neg)

3. bone scan (if x-ray non-conclusive)

4. MRI

Front 17

X-ray may be normal initially (first 3-5 days). Then what signs indicate osteomylitis?

Back 17

concurrent-

periosteal new bone formation

patchy rarefaction of metaphysis* (thinning)

metaphyseal bone destruction (erosion)*

Front 18

Indicative findings on MRI

Back 18

sinus tract extending to the cortex of bone

Front 19

Treatment for acute & chronic osteomylitis

Back 19

acute:

bactericidal antimicrobials

surgical drainage of bone abscess (if necessary)

chronic:

long term antibiotics

debridement (removal) of sequestrum

surgical drainage (if necessary)

Front 20

MC antimicrobials

Back 20

beta-lactams*

vancomycin*

cephalosporins

penicillinase-resistant penicillin

Front 21

What do you use in osteomylitis caused by a penicillin resistant organism (staph aureus)?

Back 21

nafcillin

oxacillin

cefazolin

Front 22

What organisms cause osteomyelitis in a contaminated open fracture?

Back 22

(normal skin flora)

staphylococcus (epidermis)

aerobic gram - bacillia

(also may be enterococci, fungi, atypical mycobacterium)

Front 23

Open wound/contiguous osteomyelitis infection is usually (monobacterial/polymicrobial)

Back 23

polymicrobial

Front 24

Osteomylitis infection in diabetic patients is usually (monobacterial/polymicrobial)

Back 24

polymicrobial

Front 25

Hematogenous osteomyelitis infection is usually (monobacterial/polymicrobial)

Back 25

monobacterial

Front 26

What are the two most common organisms that cause osteomyelitis via hematogenous spread?

What is also common in pts born before 1993?

Back 26

Staph aurues and strep pneumoniae

H. influenza type B

(Hib vaccine in 1993 dec substantially)

Front 27

_ and _ cause acute hematogoneous osteomyelitis in IV drug abusers

Back 27

Candida and Pseudomonas aeruginosa

Front 28

_____ & ________ cause acute hematogenous osteomylitis in neonates

Back 28

Group B strep & E coli

Front 29

Vertebral osteomyelitis accompanied by infection of the adjacent intervertebral disks is referred to as _________________

Back 29

spondylodiskitis

Front 30

Spondylodiskitis is usually caused by a hematogenous infection.

(s. aureus & coag - staph)

What may accompany it?

Back 30

psoas abscess

Front 31

Spondylodiskitis may also be caused by ________ & _________ in endemic areas

Back 31

M. tuberculosis & Brucella

Front 32

Eikenella corrodons causes _ osteomyelitis

Back 32

"needle licker"

Front 33

28 yo female presents with pain the pelvic region. She gave birth 3 weeks ago to a baby boy, and states it was a very complicated delivery. Bone scan shows increased radioisotope uptake in the pubic bone. What organisms are likely to cause this? (5)

Back 33

S. aureus, then Enterococcus sp, E Coli, Psuedomonas spp. Proteus spp (GI/Genital organsism)

Osteitis pubis (infected pubic symphysis)- requires a hx of trauma, surgery or complicated delivery.

Front 34

Pt develops a unilateral sacroiliac joint infection. What is the probable organism?

Back 34

Brucella spp

Front 35

Subacute bacterial endocarditis in IV drug abusers is likely to be caused by _

Back 35

Staph epidermidis

Front 36

An urban homeless alcoholic presents with sx of pneumonia. He also has lower back pain and pain in his right arm. MIcroscopy on silver staining reveals.....

Back 36

(extracutaneous) sporthrix


(Rose Gardener’s disease, can also cause pneumonia in urban, alcoholic homeless, osteomyelitis)

Front 37

A 28-year-old man presents with swollen, red and tender right knee joint that started about a week ago. The cause of this suspected arthritis is very likely

Back 37

N. gonorrhea

infectious (septic) arthritis in sexually active age group (16-40)

Front 38

What antimicrobial should be used in a septic arthritis pt w/ MRSA?

Back 38

*vancomycin

Front 39

What antimicrobial should you give to a pt w gram - septic arthritis (no MRSA)?

Back 39

3rd generation cephalosporin

Front 40

What antimicrobial should you give to a pt w/ gram + septic arthritis (no MRSA)?

Back 40

napsin or oxycillin

Front 41

If you cannot determine whether septic arthritis is caused by a gram + or - organism, what should you do?

Back 41

give BOTH 3rd generation cephalosporin & napsin or oxycillin

Front 42

What strain of E coli is associated with causing osteomyelitis?

Back 42

Extraintestinal pathogenic E Coli


All others cause gastroenteritis

Front 43

Who is at particular risk for developing osteomyelitis due to pseudomonas?

Back 43

IVDA and neonates.


Typically, this organism causes infection in CF and burn pts. But with regards to osteomyelitis, Iv drug abusers and neonates are at risk

Front 44

3 MC fungal cause of osteomyelitis (bone lesions) & septic arthritis in healthy individuals

Back 44

blastomycosis (skin infection)

coccidiomycosis (disseminated)

Sporothrix (extracutaneous)

Front 45

3 MC fungal causes of osteomyelitis & septic arthritis in immunocompromised individuals

Back 45

Cryptococcosis

Candidiasis

Aspergillosis

Front 46

synovial fluid:

opaque, yellow to green

variable viscosity

WBC 25,000- 100,000

PMN >75%

glucose < 25%

Back 46

septic (infectious) arthritis

Front 47

synovial fluid:

clear, yellow

high viscosity

WBC 200-2000

PMN 25-50%

glucose normal

Back 47

Osteoarthritis

(Degenerative arthritis or trauma)

Front 48

synovial fluid:

translucent, yellow or opalescent

low viscosity

WBC 2000- 20,000

PMN > 50%

glucose 50-80%

Back 48

Rheumatoid arthritis, gout

Front 49

The synovial fluid aspirate from a painful knee reveals clear and highly viscous fluid. The cell count is 500/mm3 with 30% PMN. The glucose content is nearly equal to the blood glucose level. The patient is suffering from

Back 49

Degenerative arthritis (osteoarthritis)

Front 50

Joint space widening is a characteristic X-ray finding in _________arthritis

Back 50

septic arthritis

(unlike osteomyletis, septic arthritis involves the joints not the bones)

Front 51

In olecranon bursitis, pain increases with _

In septic (bursitis) arthritis of elbow, pain increases with _

Back 51

flexion

extension

Front 52

MC causes of septic bursitis

Back 52

S. aureus

Streptococcus sp

Front 53

How do you treat septic bursitis?

Back 53

*culture directed antibiotics

-if sever- bursectomy

Front 54

Infection of prosthetics is usually due to _________ spread

Back 54

hematogenous spread

low virulence organism- s. aureus, coag neg staph (epidermis), gram - aerobic, enterococci, s viridans

Front 55

Operative cultures for prosthetic joint infection are difficult to obtain. How many must be positive to be 95% accurate on the organism?

Back 55

at least 3 positive cultures

(usually send in 5-7)

Front 56

How do you tx prosthetic joint infection?

Back 56

debridement of prosthetic (or removal)

&

antimicrobial