Infections-Hall

Question 1

A 12 year old female soccer player sustained a nasty bruise below her R knee during a particularly physical game. Two weeks later she complained of increased pain over the area accompanied by a low grade fever and sweats. She didn’t tell her parents. Her coach told her to quit complaining. However, her symptoms persisted and 2 weeks later she went to her pediatrician. Physical exam revealed a temperature of 101 F and a slightly swollen and warm left proximal tibia.
Differential?

Answer 1

staph-local infection
trauma-contusion to tibia
fracture

Question 2

What tests should be done?

Answer 2

xray
CBC
blood culture
sedimentation rate

Question 3

T/F Findings on X-rays are relatively late.

Answer 3

True.

Question 4

What tests might have been positive at the time of the trauma?

Answer 4

bone scan
MRI
higher sensitivity

Question 5

What is a bone scan?

Answer 5

radioactive tracer injected into patient. Images taken at various times after injection. Tracer absorbed by bone. Look for areas of increased uptake.

Question 6

What is the most likely organism for this infection?

Answer 6

probably staph aureus

or strep

Question 7

Does this patient need a needle biopsy?

Answer 7

it would be helpful for her
great to know which organism you’re dealing w/ & whether it is resistant
**for this pt blood culture prob won’t show organism b/c she is young & healthy

Question 8

Which antibiotics do you want to use?

Answer 8

3rd generation cephalosporin
sulfa another option
dual therapy good for penicillin resistance

Question 9

A 26 year old thrill-seeker suffered an open fracture of his right tibia and fibula while roller-blading behind a motorcycle driven by his ex-girlfriend. The fracture was reduced and fixed with the placement of screws, plates and rods. He did remarkably well until 4 months later when he noted a pimple followed by a little drainage from one of wounds. Four days later he was chasing his ex-girlfriend up some stairs and heard a loud crack and looked down to find hardware and bone protruding through his right leg.
Why did he break his leg a second time?

Answer 9

pathologic fracture

Question 10

What is the most likely organism?

Answer 10

staph or strep

Question 11

What do you send to the lab?

Answer 11

bone cultures

not sinus tract

Question 12

Usu you don’t trust the superficial culture. What is an exception?

Answer 12

when the culture yields a single organism.

Question 13

What do you do with the hardware?

Answer 13

take them out until the infection resolves & then put it back in.

Question 14

Which antibiotic should be used?

Answer 14

vancomycin-make them IV for deep infection. Eventually transition to oral antibiotics.

Question 15

What is the medical term for a bone infection?

Answer 15

osteomyelitis

Question 16

Usu what do you do with transplants that get infected?

Answer 16

remove the hardware.
resolve the infection.
put the hardware back.

Question 17

Are there situations when the prosthesis can be retained after debridement?

Answer 17

sometimes if symptoms less than 3 weeks
stable implant
easy to treat organism
maybe a strep–just use a penicillin

Question 18

Are there indications for a single stage replacement?

Answer 18

remove old hardware & same day put in a new one. 
sometimes if symptoms less than 3 weeks
soft tissue in good shape
no co-morbidities
easy to treat organism
**very rare situation

Question 19

A 39 year old IV drug user reports to the ER with fever and back pain. He mixes his drugs with dirty tap water and does not prep his skin before injecting. On exam his temperature is 39 C, he has a 3/6 holo-systolic murmur and tenderness over his thoracic spine on percussion. Neurological exam is initially normal.
Possible diagnosis?

Answer 19

endocarditis
vertebral osteomyelitis
epidural abscess

probably staph>strep>GNR>fungi

can use MRI for imaging

Question 20

Which antibiotics should be used?

Answer 20

nafcillin
gentamycin
vancomycin
gentamycin
no advantage of IV over oral

Question 21

What is mid-thoracic radicular pain indicative of?

Answer 21

spinal ache-first sign of epidural abscess

Question 22

What are the indications for debridement of vertebral osteomyelitis?

Answer 22

Instability
Abcess
Cord compression
Cervical infection
Medical failure
Neurological signs or symptoms

Question 23

What follow up imaging should be done for this patient?

Answer 23

Focus on epidural & soft tissue changes. Don’t focus on MRI too much.

Question 24

A 56 year old diabetic man visits his PCP for a routine visit. He is noted to have a 2.5 cm ulcer on the plantar surface of his foot at the first metatarsal head, extending up to the great toe. He was unaware of the ulcer; although, in retrospect, he recalls that his socks have been stained and foul smelling lately. He has not noted fevers or chills. His physician notes a hard, gritty surface at the base of the ulcer.
What is the recommended work up?

Answer 24

X-rays
CBC, ESR, CRP
MRI
Blood CUlture

**think bone involvement b/c >2 cm ulcer that is deep

Question 25

What is the best imaging available for diabetic foot infections?

Answer 25

plain film
CT
MRI
Nuclear medicine studies

Question 26

How long does it take to see X-ray evidence of a bone abnormality? How much mineral loss is required?

Answer 26

30-50% mineral loss
14 days at least
**not sensitive for acute osteomyelitis

Question 27

What is a CT good for detecting?

Answer 27

small areas of necrosis, gas, foreign bodies

Question 28

T/F Seeing a midfoot joint-centered lesion with no ulcer on MRI indicates an osteo problem.

Answer 28

False. Charcot foot.

Question 29

Usu with an infected ulcer you think staph or strep Group B…but with chronically infected ulcers what do you think?

Answer 29

staph aureus
Group B strep
enterococci
enterobacteria
pseudomonas

Question 30

With necrotic malodorous fetid foot…what organisms are responsible?

Answer 30

staph aureus
Group B strep
enterococci
enterobacteria
pseudomonas
anaerobes

Question 31

What is the recommended treatment for these extreme diabetic foot infections?

Answer 31

surgical debridement
revascularization
long term antibiotics

Question 32

YOu should always include gram + coverage for ulcers…when should you include gram negative coverage?

Answer 32

coverage for chronic wounds

Question 33

When should you add coverage for anaerobes?

Answer 33

for obviously necrotic wounds or those with a feculent odor

Question 34

HOw long does it take to treat a mild infection? A moderate-severe infection?

Answer 34

Mild Infection: 1-2 weeks

Moderate-Severe Infections: 2-4 weeks

Question 35

How long does it take to treat osteomyelitis?

Answer 35

4-6 weeks

Question 36

A 43 year old male immigrant from Pakistan reports to urgent care complaining of back pain for the last 12 months. He has lost ~15 pounds. During the last 2 weeks he noticed some mild weakness in his right leg. Examination reveals a thin, stooped, muscular male with normal vital signs. His back has a tender deformity at T6. His right knee is tender and swollen. Plain films of his T-spine show anterior wedge-shaped collapse of T6.Which organism is required?

Answer 36

TB>Staph>Other

Question 37

What diagnostic tests should be done for this patient?

Answer 37

MRI spine
PPD and CXR
Blood cultures
Biopsy
HIV
Leg films
**needs anti-TB therapy
**surgery

Question 38

What are indications for surgery in Pott’s disease?

Answer 38

Neurological deficits
Instability
Cervical disease
Medical failure including non-adherence

Question 39

What is the pathogenesis of skeletal TB?

Answer 39

US adults–skeletal TB reactivation of an old focus infection
Developing World–skeletal TB in patients with acquired TB, occurs in childhood

Question 40

What are the symptoms of skeletal TB?

Answer 40

local swelling
pain
fluctuance
systemic symptoms (fever, sweats)

Question 41

What is another name for Pott’s disease? It is responsible for 1/3 of skeletal TB cases. How does the infection go?

Answer 41

aka tuberculous spondylitis
begins in anterior aspect of vertebral body leading to anterior collapse & spread of infection along the anterior ligament
usu in the lumbar & lower thoracic spine

Question 42

A 43 year old female with a long history of rheumatoid arthritis requiring multiple joint replacements complains to her rheumatologist of a flare of her disease with pain and swelling in one of her IP joints and her right wrist. Her temperature is 37.5C, her right wrist is warm, swollen and red as is one of her IP joints on the same hand.
Why isn’t this just a flare of her RA?

Answer 42

too few joints

if infected–drain.

Question 43

A 23 year old female reports to the ER with 2 days of diffuse arthralgias, low grade fever and then the development of swelling and increased pain in her right knee and wrist. She has a new boyfriend.

Answer 43

gonorrhea–>reactive arthritis
will see skin lesions

she needs ceftriaxone for 7-10 days

Question 44

If you are less than 3 mo old which organism is responsible for pyogenic arthritis? What are the initial meds?

Answer 44

staph aureus
enterobacteria
Group B strep
Meds: PRSP + 3rd gen cephalosporin

Question 45

If you are 3 mo-6years in age…what organism is likely responsible for pyogenic arthritis? What are the initial meds?

Answer 45

staph aureus
H influenza
strep
enterobacteria
Meds:
PRSP or 1st gen cephalosporin + 3rd gen cephalosporin

Question 46

If you are an adult which organisms are responsible for pyogenic arthritis? Initial meds?

Answer 46

staph aureus
Group A strep
enterobacteria
Initial Meds:
PRSP or 1st gen cephalosporin + cipro or Timentin etc.

Question 47

If you have a joint replacement & then get pyogenic arthritis…which organism is likely responsible? WHat are the initial meds?

Answer 47

staph epidermis
staph aureus
enterobacteria
pseudomonas

Meds:
vanco + cipro or aztreonam or APAG