Lecture 3: Case Review & RMSF

Question 1

Diabetic who is slightly toxic appearing presents w/ fever, swollen extremity and ulcer w/purulent exudate, crepitus and foul smelling odor. On XR gases is seen.

1. What types of cultures should be ordered?
2. What type of bug should be suspected?
3. Before cultures come back what is the appropriate ABX tx for this pt right now?

Answer 1

Diabetic presenting w/ fever, swollen extremity and ulcer w/purulent exudate, crepitus and foul smelling odor.

1. order blood and wound cultures
2. suspect anaerobes (produce gas, crepitus, foul odor)
3. Before culture results –> give Unasyn or Zosyn

Question 2

When getting blood cultures how many sites are need and how many times must they be performed

Answer 2

blood cultures

• 2 sites
• 3 times

Question 3

What is the cause of RMSF (Rocky Mountain Spotted Fever)

- what kind of bacteria is it

Answer 3

Rickettsia Rickettsii = gram (-) aerobe

Question 4

Since RMSF has affinity for vascular endothelial cells what does this lead to in the body

Answer 4

RMSF = affinity for vascular endothelial cells –> vascular injury and microhemorrhages/infarcts

Question 5

RMSF

1. What seasons is RMSF MC?
2. Where in US is it MC (2 areas)
3. How is it spread?
4. what areas of the body are usually affected w/rash

Answer 5

RMSF:

1. MC in spring/summer
2. MC in south central/east US
3. spread by ticks
4. palms/soles usu involved

Question 6

pt presents in July w/ intense myalgias, anorexia, fever, HA, and maculopapular rash on her bilateral ankles that over the last few days has spread to her legs. She typically walks her dog in the park near her house and is worried she might have gotten poison ivy. Labs show leukopenia and thrombocytopenia. Serology results are pending

Should you wait for serology results to make Dx and Tx?
What is the suspected Dx

Answer 6

Dont wait for serology results –> deadly if untreated

Dx = RMSF

Question 7

How can you confirm the Dx of RMSF

Answer 7

Serology (IgG or M)

Question 8

Pt w/suspected RMSF who developed a rash 3 days ago is tested w/serology but the results come back negative. Does this mean that RMSF has been ruled out? why or why not?

Answer 8

NO RMSF not ruled out w/ (-) early serology results

- serology not (+) til 10-14 days after infxn

Question 9

What is the ABX Tx for RMSF

Answer 9

Doxycycline

Question 10

what type of rash is a/w a late presentation of RMSF

Answer 10

Petechial rash

• d/t vascular injury, microhemorrhages/infarcts
• leads to thrombocytopenia

Question 11

What are 3 signs of severe cases of RMSF

Answer 11

Severe RMSF

1. hemorrhage
2. necrosis
3. gangrene digits

Question 12

What is a poor prognostic sign a/w RMSF

Answer 12

meningo-encephalitis

Question 13

RMSF a/w high mortality

• what 3 pop a/w even higher risk of death?

Answer 13

RMSF and higher risk of death

1. G6PD defic
2. elderly
3. alcoholics