17. Infections - SK

Question 1

What type of antibiotic is most commonly used for prophylaxis during procedures?

Answer 1

1st gen cephalosporin (effective against common gram positive and negative organisms)

Question 2

When do wound infections usually appear after surgery?

Answer 2

Between the 5th and 10th days post-op

Question 3

Which comes first - a carbuncle or a furuncle? / Which is more common? / Which pathogen most frequently causes furuncles and carbuncles?

Answer 3

Furuncles (infected hair follicles) progress to Carbuncles (confluence of furuncles) / Furuncles are more common / STAPH

Question 4

Where do carbuncles most frequently appear?

Answer 4

Back of the neck, upper back, chest, buttocks, hips, axilla

Question 5

Treatment for furuncles? / Treatment for carbuncles?

Answer 5

Warm compress, NO antibiotics / Incision & Drainage + antibiotics

Question 6

You removed a mole from a patient’s leg. It is 6 days later and your patient returns with a fever of 100.4. Upon inspection, you note the skin of his leg is now brawny red, edematous, and warm to the touch. The area of redness has an ill-defined border. What’s going on?

Answer 6

Cellulitis

Question 7

What 2 organisms most frequently cause cellulitis? / How do you typically treat it?

Answer 7

Strep and Staph / Warm packs and elevation + antibiotics

Question 8

Which antibiotics work best against cellulitis?

Answer 8

Penicillin or 1st gen cephalosporin

Question 9

Which of the post-op infections likely presents with fever, compartment syndrome, muscle edema, cramping within one muscle group, and overlying necrosis? Aspiration of infected area reveals pus. / Treatment?

Answer 9

Pyomyositis = purulent infection of skeletal muscle / Drainage + broad-spectrum antibiotics

Question 10

What pathogen most frequently causes pyomyositis?

Answer 10

Staph = #1 (strep = #2)

Question 11

Your patient presents with a foul-smelling leg wound that has been getting rapidly worse. The wound is red-brown, edematous, and covered in blisters containing bluish-maroon fluid. Blisters & tissue slough off easily and there is substantial crepitus. What’s likely going on?

Answer 11

Gas Gangrene

Question 12

If you biopsy a wound infected with gas gangrene, what organism is very likely to grow? / How fast does gas gangrene progress?

Answer 12

Clostridium perfringens / several inches per hour - this is an EMERGENCY, people!

Question 13

What 3 things are done to treat gas gangrene infections? / What is the incubation time for gas gangrene?

Answer 13

1) SURGERY (urgent debridement or amputation if necessary), 2) Broad spectrum Abx, 3) Hyperbaric Oxygen / 6 hrs to 4 days (i.e. shorter than most)

Question 14

T/F: The only definitive way to diagnose gas gangrene is to obtain imaging that reveals gas bubbles?

Answer 14

False - gas only appears on imaging half of the time.

Question 15

A 64-year old patient who is 8 days status post right total knee arthroplasty presents to your urgent care with a chief complaint of “I have 9/10 pain at my surgical site - it hurts so bad!.” The patient has a fever of 102.4 F. The skin around the surgical site is brawny-red and warm. The patient feels nauseous and ill. The pain extends well beyond the border of cutaneous erythema. What’s going on?

Answer 15

Necrotizing Fasciitis!! This condition can look like cellulitis but the patient will be in TONS of pain & pain often extends BEYOND the area associated with cutaneous changes.

Question 16

What organisms tend to cause necrotizing fasciitis?

Answer 16

1) Staph or Strep, 2) Clostridium perfringens

Question 17

What is the treatment for necrotizing fasciitis?

Answer 17

Debridement and drainage + broad spectrum abx

Question 18

What finding during surgery confirms the diagnosis of necrotizing fasciitis?

Answer 18

Edematous, dull-gray and necrotic fascia and subcutaneous tissue

Question 19

Which antibiotics are typically used together to treat necrotizing fasciitis? / True or False: In mild cases of necrotizing fasciitis, antibiotics can be used without surgical intervention.

Answer 19

Pen or ceph + aminoglycoside + clindamycin / FALSE - abx are useless without surgical intervention.

Question 20

Gas gangrene and necrotizing fasciitis can present similarly. Both can have foul smell, hemorrhagic bullae, and crepitus. Why is it critical to differentiate gas gangrene infection from necrotizing fasciitis?

Answer 20

With necrotizing fasciitis, you can usually salvage the limb! It would be terrible to amputate a limb when debridement would have worked.

Question 21

What is Streptococcal Toxic Shock Syndrome?

Answer 21

When necrotizing fasciitis is caused by Group A strep & it progresses to shock and multisystem organ failure.

Question 22

Collection of pus that can occur anywhere in the body is called?

Answer 22

Abscess

Question 23

Abscesses are often associated with fever and pain at the surgical site. What is another CLASSIC symptom associated with abscesses?

Answer 23

Fluctuance (also - sutures might appear tight d/t edema)

Question 24

Treatment for superficial abscesses? / Treatment for deep abscesses? / What can abscesses lead to if not treated right away?

Answer 24

Open and drain + abx / Drain by placing percutaneous catheter + abx / Sinus tracts & fistulas

Question 25

You are rounding on a patient who is 10 days status post abdominal surgery. The patient has been experiencing fever, anorexia, and weight loss. When you examine the surgical site, you note what appears to be fecal contents oozing through the sutures. What do you think is going on?

Answer 25

Abdominal abscess progressed to FISTULA connecting bowel and open skin.

Question 26

What is the definition of a fistula?

Answer 26

Abnormal connection between two epithelial surfaces (derived fr Latin word for pipe)

Question 27

Treatment for fistula?

Answer 27

Drain abscess + antibiotics. Pt will likely need PPN or TPN if abdominal fistula d/t inability to eat.

Question 28

You have been seeing a patient with a post-op infection. The patient is now experiencing delirium, hypoxia, signs of shock, and oliguria. What do you suspect? / What do you order?

Answer 28

Pt has gone septic / blood cultures

Question 29

What is the definition of bacteremia? / Does it always progress to sepsis?

Answer 29

Bacterema = bacteria in the blood; asymptomatic. / No. In some instances (i.e following dental work, GI tract surgery, or UTI), bacteria is released into the blood stream but can be cleared just fine w/o intervention.

Question 30

What is the definition of septicemia?

Answer 30

A localized infection has exceeded the body’s ability to contain it and is now a system-wide inflammatory response.

Question 31

What is the difference between sepsis and SIRS?

Answer 31

Sepsis = systemic response due to infection; SIRS = systemic response due to NON-infectious cause (i.e. burns, hemorrhage, surgery complications, etc)

Question 32

Weak cough & impaired clearing mechanisms after surgery can make patients vulnerable to contracting what type of infection?

Answer 32

Aspiration of oropharyngeal secretions –> PNEUMONIA

Question 33

What can be done post-op to lower a patient’s risk of developing pneumonia?

Answer 33

1) Encourage coughing and respiratory exercises - like incentive spirometry, 2) Control pain (uncontrolled pain –> shallow breathing)

Question 34

What two pathogens that are associated with ventilator-contracted pneumonia have led to epidemics in the ICU?

Answer 34

Pseudomonas aeruginosa & klebsiella pneumonia

Question 35

What bug most frequently causes UTIs?

Answer 35

E coli

Question 36

The longer a catheter is left in place, the more likely bacterial colonization becomes. Colonization occurs in ____% of patients after the catheter is left in place for 5 days?

Answer 36

95% (yikes - but that’s what Current says)

Question 37

To prevent reflux of urine, catheters should have an airlock or _____ valve. To further prevent infection, how should catheters be placed?

Answer 37

One-way / Non-obstructed (i.e. no kinks in tubing) and DEPENDENT (lower than the patient - don’t hang from bed rails above bladder-height)

Question 38

True or False: All post-op wound infections require antibiotics.

Answer 38

False - Antibiotics are only necessary if the infection is invasive. Wound might respond to I&D alone.

Question 39

What is the most common pathogen implicated in acute osteomyelitis after total joint replacement?

Answer 39

Staph aureus