Skin and Soft tissue infections

Question 1

what is impetigo?

Answer 1

superficial skin infection, presents with multiple vesicular lesions on an erythematous base and has a golden crust, common on face, extremities and scalp

Question 2

Common cause of impetigo?

Answer 2

staph aureus,
strep pyogenes (less common)

Question 3

Risk factors of impetigo?

Answer 3

2-5 years,
skin abrasions, 
minor trauma, 
burns, 
poor hygiene, 
insect bites, 
chickenpox, 
eczema, 
atopic dermatitis

Question 4

Treatment of impetigo?

Answer 4

topical antibiotics (sometimes + oral)

Question 5

what is erysipelas?

Answer 5

infection of the upper dermis,
red and painful area + fever and regional lymphadenopathy and lymphangitis,
has distinct elevated borders

Question 6

what commonly causes erysipelas?

Answer 6

strep pyogenes

Question 7

risk factors of erysipelas?

Answer 7

areas of pre-existing lymphoedema, 
venous stasis, 
obesity, 
paraparesis, 
dm

Question 8

what is cellulitis?

Answer 8

skin infection involving deep dermis and subcutaneous fat,
spreading erythematous area with no distinct borders,
fever, regional lymphadenopathy and lymphangitis present

Question 9

predisposing factors of cellulitis?

Answer 9

diabetes mellitus,
tinea pedis,
lymphoedema,
lymphangitis

Question 10

Most likely organisms that causes cellulitis

Answer 10

strep pyogenes,

staph aureus

Question 11

treatment of erysipelas and cellulitis

Answer 11

flucloxacillin

Question 12

what is the most common organism causing folliculitis

Answer 12

staph aureus

Question 13

what is furunculosis?

Answer 13

single hair-follicle-associated inflammatory nodule,
extends into dermis and subcutaneous tissue,
usually affects face, axilla, neck, buttocks

Question 14

furunculosis causative organism?

Answer 14

staph aureus

Question 15

furunculosis risk factors?

Answer 15

obesity, 
dm, 
atopic dermatitis, 
chronic kidney disease, 
corticosteroid uses

Question 16

what is a carbuncle?

Answer 16

infection extends to involve multiple furuncles,
back of neck, posterior trunk or thigh,
purulent material expressed

Question 17

carbuncle treatment?

Answer 17

iv antibiotics

Question 18

predisposinf conditions to necrotising fasciitis

Answer 18

dm, 
surgery, 
trauma, 
peripheral vascular disease,
skin popping

Question 19

what is type 1 necrotising fasciitis

Answer 19

mixed aerobic and anaerobic infection

Question 20

typical organisms causing type 1 necrotising fasciitis

Answer 20

streptococci, 
staphylococci, 
enterococci, 
gram -ve bacilli, 
clostridium

Question 21

typical organisms causing type2 necrotising fasciitis

Answer 21

strep pyogenes

Question 22

necrotising fasciitis presentation

Answer 22

erythema, 
extensive oedema, 
severe pain,
haemorrhagic bullae, 
skin necrosis, 
crepitus, 
fever, 
hypotension, 
tachycardia, 
delirium, 
mutiorgan failure

Question 23

treatment of necrotising fasciitis

Answer 23

surgical review,

broad spectrum antibiotics (flucloxacillin, gentamicin, clindamycin)

Question 24

what is pyomyositis?

Answer 24

purulent infection deep within striated muscle,

manifests as an abscess

Question 25

common sites of pymyositis?

Answer 25

``` thigh, calf, arms, gluteal region, chest wall, psoas muscle ```

Question 26

presentation of pyomyositis?

Answer 26

fever, pain, woody induration of affected muscle

Question 27

predisposing factors of pyomyositis

Answer 27

``` dm, HIV/ immunocompromised, IDU, rheumatological diseases, malignancy, liver cirrhosis ```

Question 28

common cause of pyomyositis

Answer 28

staph aureus

Question 29

pyomyositis investigations?

Answer 29

CT/ MRI, | gram stain

Question 30

treatment of pyomyositis

Answer 30

drainage and antibiotic cover

Question 31

predisposing factors for septic bursitis

Answer 31

``` rheumatoid arthritis, alcoholism, DM, IDU, immunosuppresion, renal insufficiency ```

Question 32

presentation of septic bursitis?

Answer 32

``` peribursal cellulitis, swelling, warmth, fever, pain on movement ```

Question 33

Diagnosis of septic bursitis

Answer 33

aspiration of fluid, | common cause is staph aureus

Question 34

what is infectious tenosynovitis

Answer 34

infection of the synovial sheats that surround tendons

Question 35

common cause of infectious tenosynovitis?

Answer 35

staph aureus and stretococci, | penetrating trauma most commonly incites event

Question 36

presentation of infectious tenosynovitis?

Answer 36

erythematous fusiform swelling of finger, held in semiflexed position, tenderness over tendon sheat, pain on extension

Question 37

treatment of infectious tenosynovitis?

Answer 37

empiric antibiotics, | hand surgeon

Question 38

diagnostic criteria for staphylococcal toxic shock syndrome?

Answer 38

fever, hypotension, diffuse macular rash, 3 of following organs involved- liver, blood, renal, gi, cns, muscular, isolation of staph aureus form mucosal or normally sterile site, production of TSST1 by isolate, development of antibody to toxin

Question 39

treatment of toxic shock syndrome?

Answer 39

``` remove offending agent, IV fluids, inotropes, antibiotics, IV immunoglobulins ```

Question 40

what is panton-valentine leucocidin toxin?

Answer 40

gamma haemolysin, can cause SSTI and haemorrhagic pneumonia, presents with recurrent boils

Question 41

risk factors for IV-catheter associated infections?

Answer 41

continuous infusion >24 hours, cannula in situ >72 hours, cannula in lower limb, patients with neurological/ neurosurgical problems

Question 42

Cause of IV-catheter associated infections

Answer 42

staph aureus, | forms biofilm which spills into bloodstream

Question 43

treatment of IV-catheter associated infections

Answer 43

remove cannula, express any pus from thrombophlebitis, antibiotics for 14 days, echocardiogram

Question 44

class 1 of surgical site infections?

Answer 44

clean wound

Question 45

class 2 of surgical site infections?

Answer 45

clean-contaminated wound

Question 46

class 3 of surgical site infections?

Answer 46

contaminated wound

Question 47

class 4 of surgical site infections?

Answer 47

infected wound

Question 48

procedural risk factors for surgical site infections?

Answer 48

``` shaving of site night prior to procedure, improper preoperative skin preparation, improper antimicrobial prophylaxis, back in sterile technique, inadequate theatre ventilation, perioperative hypoxia ```