Surgery - Surgical Infection & Antibiotics

Question 1

What general factors contribute to wound infection following a surgical procedure?

Answer 1

Age
Malnutrition
Immunosuppression
Malignancy
Obesity
Hypoxia
Anaemia

Question 2

What local factors contribute to wound infection following a surgical procedure?

Answer 2

Type of surgery (clean vs contaminated)
Length of procedure
Residual local malignancy
Foreign body insertion
Ischaemia

Question 3

What microbiological factors contribute to wound infection following a surgical procedure?

Answer 3

Lack of a/b prophylaxis

Virulence of organism

Question 4

What are the four types of operative procedure, in reference to their potential for infectious complications?

Answer 4

Clean
Potentially-contaminated
Contaminated
Dirty

Question 5

Describe a clean operative procedure

Answer 5

Operation does not enter colonised viscus or lumen of body
SSI risk from contaminants from environment (2-5%)
-S. aureus most common

Question 6

Describe a potentially-contaminated procedure

Answer 6

Operation enters colonised viscus or body cavity but under elective & controlled conditions
SSI risk from endogenous bacteria (10%)

Question 7

Describe a contaminated procedure

Answer 7

Contamination present at surgical site w/o obvious infection

SSI risk from endogenous bacteria (20%)

Question 8

Describe a dirty procedure

Answer 8

Surgery performed where active infection already present

SSI risk from established pathogens (30%)

Question 9

What are the three types of surgical site infection?

Answer 9

Superficial Incisional
Deep Incisional
Organ/space

Question 10

What is a Superficial Incisional SSI?

Answer 10

Infection of skin & s.c. tissue of incision

Question 11

What is a Deep Incisional SSI?

Answer 11

Infection of deep tissues (muscle/fascial) and includes organ/space SSIs draining through the incision

Question 12

What is an Organ/Space SSI?

Answer 12

Infection of any site involved in the operation other than the incision

Question 13

Which patients should be given prophylactic infection?

Answer 13

Pts at high risk of infection

Pts where an infection would be serious, even if risk is low

Question 14

What determines choice of antibiotic in surgical pts?

Answer 14

Likely infecting organisms
Hospital guidelines
-cefuroxime & metronidazole

Question 15

What is impetigo?

Answer 15

Superficial purulent infection caused by staph/strep w/ golden crust on erythematous base

Question 16

How should impetigo be managed?

Answer 16

Swab to confirm organism

Treat w/ topical mupirocin/fusidic acid

Question 17

What is ecthyma?

Answer 17

Purulent skin infection caused by staph/strep. Ulceration under a crust

Question 18

How should ecthyma be managed?

Answer 18

Associated w/ poor hygiene & malnutrition

Treat by guidelines

Question 19

What is erythrasma?

Answer 19

Mildly itchy eruption b/w toes/flexures caused by corynebacterium

Question 20

How should erythrasma be managed?

Answer 20

Topical miconazole OR

Oral erythromycin

Question 21

What is Folliculitis?

Answer 21

Pustular infection caused by staph

-can be deep or superficial

Question 22

How should folliculitis be managed?

Answer 22

Oral flucloxacillin (if superficial)
Tetracycline/erythromycin (if deep)

Question 23

What is Staphylococcal Scalded Skin Syndrome?

Answer 23

Fever, irritability & skin tenderness THEN

Erythema & blistering (after 24-48hrs)

Question 24

How should SSSS be managed?

Answer 24

Bacterial swab from nose/throat

IV flucloxacillin

Question 25

What is Cellulitis?

Answer 25

Infection of s.c. tissue due to staph

Question 26

What is Erysipelas?

Answer 26

Infection of dermis due to staph Raised erythematous edge Often on face

Question 27

What are Viral Warts?

Answer 27

Smooth, skin coloured papules w/ irregular hyperkeratotic surface -resolve spontaneously

Question 28

What is Molluscum Contagiosum?

Answer 28

Poxvirus causing umbilicated papules | -resolve spontaneously over months

Question 29

What is Ringworm?

Answer 29

Erythematous annular lesions w/ central clearing

Question 30

How should Ringworm be managed?

Answer 30

Topical terbinafine/ketoconazole | -may be systemic in widespread disease

Question 31

What is Scabies?

Answer 31

Scabietic burrows on edges of fingers/sides of hands/feet

Question 32

How should Scabies be managed?

Answer 32

Topical permethrin/malathion | -give to all physical contacts

Question 33

What are the two broad types of gangrene?

Answer 33

Anaerobic | Synergistic (necrotising fasciitis)

Question 34

What causes anaerobic gangrene?

Answer 34

Clostridium perfringens in soil/faeces - arises from trivial injury - often in immunocompromised pts

Question 35

How does anaerobic gangrene present?

Answer 35

Gas in tissues & skm (crepitus) Oedema Spreading gangrene w/ systemic upset

Question 36

How should anaerobic gangrene be managed?

Answer 36

Resuscitation Aggressive debridement IV penicillin + metronidazole

Question 37

What causes synergistic gangrene?

Answer 37

Aerobes & synergistic anaerobes infect wound/surgical site

Question 38

How does synergistic gangrene present?

Answer 38

Severe wound pain Gas in tissues Extensive subdermal gangrene

Question 39

How should synergistic gangrene be managed?

Answer 39

Debridement Antibiotics Systemic support

Question 40

What are the causes of post-op fever?

Answer 40

``` Mild pyrexia common post-op (response to tissue injury/stress) Severe pyrexia (infection) ```

Question 41

What general steps should be taken when reviewing a patient with post-op fever?

Answer 41

Review general obs, urine output etc. Inspect wound for SSI/haematoma Inspect cannula sites for thrombophlebitis/infection Examine chest for infection/infarction/acute heart failure Examine legs for DVT Consider other sources of infection

Question 42

When is a routine isolation unit used?

Answer 42

Protect other pts/staff from pts infection

Question 43

When are reverse isolation units used?

Answer 43

Protect pts from infections carried by staff/visitors/pts | -used when pts have decreased immunity

Question 44

What are the common locations of an intra-abdominal abscesses?

Answer 44

Alongside organ of origin Pelvic Subphrenic

Question 45

What are the clinical features of an intra-abdominal abscesses?

Answer 45

``` Malaise Anorexia Swinging pyrexia Tachycardia Possible mass ```

Question 46

How are intra-abdominal abscesses investigated?

Answer 46

CT abdo/pelvis

Question 47

How are intra-abdominal abscesses managed?

Answer 47

IV empirical a/b Radiologically guided drainage -surgical drainage as last line

Question 48

How should a superficial s.c. abscess be drained?

Answer 48

Performed under GA Fluctuance incised Blunt probing ensures all loculi drained