Micro & Infections

Question 1

What are the 4 G- rods with animal reservoirs?

Answer 1

brucella
francisella
pasteurella
bartonella

Question 2

Features of Brucella

Answer 2

facultative intracellular

granuloma forming

Question 3

How is Brucella transmitted?

Answer 3

transmitted through drinking contaminated milk or skin during butchering

Question 4

How does Brucella present?

Answer 4

joint/back pain
flu-like symptoms
depression
travel/unpasteurized milk history
blood cx negative because it has a long incubation period

Question 5

How is Brucella treated?

Answer 5

6 wk combo:
doxycycline
streptomycin or rifampin

Question 6

How is tularemia transmitted?

Answer 6

transmitted by ticks/flies from rabbits or cutaneous exposure to an infected animal

Question 7

What is the disease caused by Francisella?

Answer 7

Tularemia

Question 8

Features of Francisella

Answer 8

G- rod

found in central US

Question 9

How does tularemia present?

Answer 9

ulcerations
fevers/muscle aches
painful axillary lymph nodes
exposure to rabbits or ticks

Question 10

How is tularemia diagnosed?

Answer 10

serology

Question 11

How is tularemia treated?

Answer 11

2 wks of 1:
streptomycin
gentamycin
doxycycline

Question 12

What does Pasteurella look like under methylene blue?

Answer 12

bipolar staining

Question 13

How is Pasteurella transmitted?

Answer 13

dog or cat bites

Question 14

What infections does pasteurella cause?

Answer 14

osteomyelitis
endocarditis
meningitis

Question 15

What is cat scratch disease?

Answer 15

Bartonella

Question 16

How does Bartonella present?

Answer 16

fever
lymph nodes
bacillary angiomatosis in immunocompromised pts

Question 17

What disease does Bacillus anthracis cause?

Answer 17

anthrax

Question 18

How does anthrax present?

Answer 18

cutaneous:
pigmented eschar
edema
Inhalation (wool-sorter's disease):
hemorrhagic mediastinitis
sepsis

Question 19

What dz does Borrelia burgdorferi cause?

Answer 19

Lyme

Question 20

Where does Lyme occur?

Answer 20

New England

Question 21

How long does it take a tick to transmit Borrelia?

Answer 21

36-72 hrs

Question 22

What rash is ass’d with Lyme?

Answer 22

erythema migrans

Question 23

What are early signs of Lyme? (within 1 month)

Answer 23

fever/chills
headache
muscle/joint pain
lymph nodes
erythema migrans

Question 24

What are the late signs of Lyme? (over 1 month)

Answer 24

severe headache/neck stiffness
facial palsy
more erythema migrans rashes
arthritis w/ severe pain/swelling

Question 25

How is Dengue virus transmitted?

Answer 25

Aedes mosquitoes

Question 26

How does Dengue fever present?

Answer 26

severe fever rash leukopenia severe muscle/joint pain

Question 27

How does Dengue hemorrhagic fever present?

Answer 27

dengue fever | progresses to hemorrhagic shock

Question 28

How many serotypes exist of Dengue?

Answer 28

4

Question 29

What is antibody-enhanced disease?

Answer 29

antibodies recognize but don't destroy new serotype antibody-coated virus is taken up more quickly by cells complement fixation leads to more vascular permeability

Question 30

What most commonly infects joint replacements?

Answer 30

staph epi

Question 31

What most commonly infects native joints?

Answer 31

staph aureus most common overall | Neisseria gonorrhoeae common in sexually active individuals

Question 32

How is septic arthritis diagnosed?

Answer 32

cloudy fluid with >20,000 PMN/ul and low glc compared to BG

Question 33

What is Pott's disease?

Answer 33

spinal TB from hematologic spread

Question 34

Who gets bone/joint infections with nontyphoid Salmonella?

Answer 34

sickle cell pts | expanded bone marrow with low blood flow

Question 35

Where does osteomyelitis infect in kids and adults?

Answer 35

kids: metaphysis of long bones (doesn't spread to joint) adults: vertebral bodies, metaphysis spreading to joint

Question 36

Why are metaphyses more likely to be infected?

Answer 36

vessels make hairpin turns and have slow blood flow

Question 37

What osteomyelitis changes are seen on x-ray?

Answer 37

lytic lesions at the abscess

Question 38

Which joints have a physis within the joint capsule? Why is this important?

Answer 38

``` allows direct spread on infection to joint distal fibula radial head/neck proximal humerus proximal femur ```

Question 39

How does osteomyelitis present?

Answer 39

local pain fever tenderness elevated ESR, CRP

Question 40

How long does it take for osteomyelitis to show up on x-ray?

Answer 40

1-2 wks

Question 41

How is osteomyelitis treated?

Answer 41

antibiotics (oral/IV/local) | I&D or debriedment

Question 42

What are osteomyelitis complications?

Answer 42

infectious arthritis chronic infection recurrent infections

Question 43

How does chronic osteomyelitis appear on x-ray?

Answer 43

``` "bone within a bone" new bone (involucrum) growing around the dead bone (sequestrum) ```

Question 44

What is a Marjolin ulcer?

Answer 44

squamous cell carcinoma in a sinus tract or burn

Question 45

How is chronic osteomyelitis treated?

Answer 45

antibiotics remove sequestra or implants establish blood supply

Question 46

What is a commonly infected joints in IV drug users?

Answer 46

SC joint

Question 47

What are the most commonly infected joints?

Answer 47

hips | knees

Question 48

What are complications of septic arthritis?

Answer 48

synovial cell death chondrolysis condrocyte death All begin within 24 hrs

Question 49

How does septic arthritis present? Diagnosed?

Answer 49

inflammation and effusion ID effusion with ultrasound/MRI Diagnosed with joint aspiration

Question 50

What is a potential cause of an infected shoulder replacement?

Answer 50

P acnes