Soft tissue inf.

Question 1

What organism is usually responsible for “hot tub” folliculitis?

Answer 1

-Pseudomonas aeruginosa

Question 2

What kind of infection are patients who have undergone saphenous vein harvesting?

Answer 2

Cellulitis/Erysipelas with venous & lymphatic compromise

-Streptococcus

Question 3

What organism is usually responsible for lymphangitis?

Answer 3

-S. Pyogenes

Question 4

What is included in the differential dx of a rapidly progressive necrotizing soft tissue infection?

Answer 4

• Group A streptococci (S. pyogenes);
• Vibrio species;
• Aeromonas species;
• Clostridium species;
• Rarely, Staphylococcus aureus (CA-MRSA)

Question 5

Clostridial myonecrosis denotes invasion of ____________ (even spontaneously) by C. perfringens, C. novyi or C. septicum.

Answer 5

healthy muscle

**C. septicum is frequently associated with underlying systemic malignancy (e.g., colon cancer).

Question 6

What is the Therapy of Clostridial Gangrene/Myonecrosis?

Answer 6

Therapy includes immediate aggressive surgical debridement/amputation & high dose penicillin

-add clindamycin to decrease toxin production

Question 7

What is the Therapy of Life-Threatening Group A Streptococcal Infections, ie Toxic shock syndrome?

Answer 7

• Aggressive surgical debridement or amputation is frequently needed.
• ?? Hyperbaric oxygen (if it is available).
• Intravenous immunoglobulin has been shown to be of some theoretical benefit in 2 trials:

Question 8

Who is more susceptible to necrotizing soft tissue infections due to Vibrio species?

Answer 8

-Individuals compromised by cirrhosis, AIDS, or malignancy

Question 9

Rapidly progressive cellulitis or necrotizing fasciitis due to ___________occurs in the setting of an injury related to fresh water exposure. The syndrome that results may be identical to that produced by Vibrio species.

Answer 9

Aeromonas hydrophila

*also think medicinal leeches

Question 10

What is fournier’s gangrene?

Answer 10

• Necrotizing perineal infections,that occur most frequently in diabetics and patients with granulocytopenia
• Microbiology reflects mixed bowel flora

Question 11

What is Meleney’s gangrene?

Answer 11

• Post-surgical mixed infection;
• Microbiology reflects site of surgery (e.g., intra-abdominal flora).

Question 12

What is Ludwig’s angina?

Answer 12

• Polymicrobial infection of submandibular & submental spaces;
• Bacteriology reflects complex oral flora.

Question 13

Only_______of Foot Infections in Diabetics is Due to Vascular Disease/

Answer 13

15%

Question 14

________ of Foot Infections in Diabetics is Due to Neuropathy

Answer 14

85%

Question 15

The most common pathophysiologic process leading to diabetic foot infections is:

a. Peripheral vascular disease
b. Hyperglycemia
c. Neuropathy
d. Depressed neutrophil function

Answer 15

c. Neuropathy

Question 16

Your roommate was celebrating his 21st birthday, injudiciously as it turns out, and lost all of his inhibitions due to alcohol. He happened to provoke a fight with a big guy in the bar and punched him in the mouth. 28 hours later, his right hand began to swell at the 2nd & 3rd metacarpal-phalangeal joints over some lacerations that he suffered. The bacteriology most likely includes:

a. Enterococcus faecalis
b. Streptococcus iniae
c. Pseudomonas aeruginosa
d. Anaerobic organisms (Veilonella, Peptostreptococcus, Fusobacterium)

Answer 16

d. Anaerobic organisms (Veilonella, Peptostreptococcus, Fusobacterium) =Clenched fist injury

Question 17

36 hours ago, while trying to pet it, your neighbor’s cat bit you on the hand. Your index finger is now swollen & tender. The bacteriology likely includes:

a. Streptococcus zooepidemicus
b. Enterococcus faecium
c. Pseudomonas aeruginosa
d. Pasteurella multocida

Answer 17

d. Pasteurella multocida

Question 18

The hand surgeons consulted you to help with management of an infection in a 34-year-old man who had amputated his right index finger in a snow blower 5 days ago. They reattached his finger, but it is now red, tender and swollen and a culture is growing an aerobic, gram-negative rod. You suspect the infection was caused by:

A. Pseudomonas aeruginosa that contaminated the snow blower blades.

B. Nosocomial Klebsiella pneumoniae infection.

C. Aeromonas hydrophila from medicinal leaches used to maintain blood vessel patency.

D. Fusobacterium from his mouth

Answer 18

C. Aeromonas hydrophila from medicinal leaches used to maintain blood vessel patency.

Question 19

This 28-year-old man returned last night from a 4-day ski trip in Aspen. Yesterday, he began to develop this rash confined to his chest & below. He spent a lot of time drinking beer in the hot tub. It is likely caused by:

a. Streptococcus pyogenes
b. Staphylococcus epidermidis
c. Streptococcus iniae
d. Pseudomonas aeruginosa

Answer 19

d. Pseudomonas aeruginos

Question 20

24 hours ago, while trying to unhook this fish from his line, a 42-year-old cirrhotic Gulf fisherman stepped on the dorsal fin which penetrated his foot. Now, he presents with a rapidly progressive necrotizing cellulitis of the foot and leg. The most likely organism causing this is:

A. Streptococcus pyogenes

B. Aeromonas hydrophila

C. Vibrio vulnificus

D. Pseudomonas aeruginosa

Answer 20

C. Vibrio vulnificus Salt Water*

Question 21

The hand surgeons biopsied this abnormal bone 2 days ago; the culture is growing Eikenella corrodens. This likely resulted from:

A. Penetration from a fishing hook

B. A dog bite

C. Human bite/saliva contamination

D. Bacteremic spread from endocarditis

Answer 21

C. Human bite/saliva contamination

Question 22

This 72-year-old man presented with pain in the left arm. On examination, it feels to you like Rice Krispies. Gram stain shows no neutrophils. What is the organism?

A. Streptococcus anginosus

B. Pseudomonas aeruginosa

C. Clostridium septicum

D. Aeromonas hydrophila

Answer 22

C. Clostridium septicum

Question 23

While feeding this squirrel in Hermann Park, your girlfriend was bitten on the finger. Management should include:

A. Tetanus immunization

B. Rabies immunization

C. Prophylactic azithromycin

D. Both a & b

Answer 23

A. Tetanus immunization

Question 24

A patient with a necrotizing ulcer on his scrotum likely has underlying:

A. Burn

B. Diabetes mellitus

C. Zipper trauma

D. Hidradenitis suppurativa

Answer 24

B. Diabetes mellitus

Question 25

This 25-year-old man injured his leg while waterskiing in Lake Conroe. There are hemorrhagic bullae. The causative organism is likely to be:

A. Aeromonas hydrophila

B. Vibrio vulnificus

C. Streptococcus pyogenes

D. Staphylococcus aureus

Answer 25

A. Aeromonas hydrophila

**FRESH WATER