Skin and Soft Tissue Infections Flashcards
(47 cards)
1
Q
What are the features of impetigo?
A
- Superficial skin infection
- Highly infectious
- Multiple vesicular lesions on an erythematous base
- Golden crust
- Usually on exposed parts of the body
2
Q
Which organisms can cause impetigo?
A
- Staph aureus (common)
- Strep pyogenes (less common)
3
Q
What are the predisposing factors for impetigo?
A
- Skin abrasions
- Minor trauma
- Burns
- Poor hygiene
- Insect bites
- Chickenpox
- Eczema
- Atopic dermatitis
4
Q
How can impetigo be treated?
A
- Small areas: topical antibiotics
- Large areas topical treatment and oral antibiotics
5
Q
What are the features of erysipelas?
A
- Infection of the upper dermis
- Painful, red area
- Fever, lymphadenopathy and lymphangitis
- Mostly affects the lower limbs
- Distinct elevated borders
- Tends to occur in areas of pre-existing lymphoedema, venous stasis, obesity, paraparesis and diabetes
6
Q
Which organism commonly causes erysipelas?
A
Strep pyogenes
7
Q
What are the features of cellulitis?
A
- Skin infection involvin deep dermis and subcut fat
- Spreading erythematous area
- Fever
- Regional lymphadenopathy and lymphangitis
- Predisposing factors: diabetes, tinea pedis and lymphoedema
8
Q
Which organisms commonly cause cellulitis?
A
- Strep pyogenes
- Staph aureus
- Gram negatives in diabetics and febrile neutropaenics
9
Q
How can erysipelas and cellulitis be treated?
A
- Combination of anti-staph and anti-strep antibiotics
- Extensive disease: IV antibiotics and rest
10
Q
What is folliculitis and how does it present?
A
- Circumscribed, pustular infection of a hair follicle
- Small red papules
- Central area may rupture and drain
- Head, back, buttocks and extremities
11
Q
Which organism commonly causes folliculitis?
A
Staph aureus
12
Q
What are the features of furunculosis?
A
- Boils
- Single hair follicle associated inflamm. nodule
- Extends into dermis and subcut tissue
- Affects moist, hairy, friction prone areas
13
Q
Which organism commonly causes furunculosis?
A
Staph aureus
14
Q
What are the risk factors for furunculosis?
A
- Obesity
- Diabetes
- Atopic dermatitis
- Chronic kidney disease
- Corticosteroid use
15
Q
What is a carbuncle and what are the features of them?
A
- Infection which has extended to involve multiple furuncles
- Multiseptated abscesses
- Purulent material
16
Q
How are hair-associated infections treated?
A
- Folliculitis: no treatment
- Furunculosis: if not improving then oral antibiotics
- Carbuncles: may require admission, surgery and IV antibiotics
17
Q
What are the predisposing conditions for necrotising fasciitis?
A
- Diabetes
- Surgery
- Trauma
- Peripheral vascular disease
- Skin popping
18
Q
What is type 1 necrotising fasciitis and which organisms typically cause it?
A
- Mixed aerobic and anaetobiv infection (diabetic foot infection and Fournier’s gangrene)
- Strep, staph, enterococci, gram negative bacilli and clostridium
19
Q
What is type 2 necrotising fasciitis and which organism typically causes it?
A
- Monomicrobial
- Strep pyogenes
20
Q
What are the features of necrotising fasciitis?
A
- Rapid onset
- Erythema, oedema and severe pain
- Haemorrhagic bullae, skin necrosis and crepitus
- Fever, hypotension, tachycardia, delirium and multiorgan failure
- Anaesthesia at site of infection
21
Q
How is necrotising fasciitis managed?
A
- Surgical review
- Broad spectrum antibiotics: fluclox, gentamicin and clindamycin
22
Q
What is pyomyositis?
A
Purulent infection deep within striated muscle often as an abscess
23
Q
What are the common sites for pyomyositis?
A
- Thigh
- Calf
- Arms
- Gluteal region
- Chest wall
- Psoas muscle
24
Q
How does pyomyositis present?
A
- Fever
- Pain
- Woody induration of affected muscle
- Can lead to septic shock and death
25
What are the predisposing factors for pyomyositis?
- Diabetes
- HIV/ immunocompromised
- IVDA
- Rheumatological diseases
- Malignancy
- Liver cirrhosis
26
Which organisms can cause pyomyositis?
- Staph aureus
| - Gram positives/negatives, TB and fungi
27
How is pyomyositis investigated and how is it treated?
- CT/MRI, gram stain and culture
| - Specific antibiotics
28
What are the predisposing factors for septic bursitis?
- Rheumatoid arthritis
- Alcoholism
- Diabetes mellitus
- IVDA
- Immunosuppression
- Renal insufficiency
29
What are the features of septic bursitis?
- Peribursal cellulitis
- Swelling
- Warmth
- Fever
- Pain on movement
30
How is septic bursitis diagnosed and which organisms are involved?
- Aspiration
- Most common is staph aureus
- Gram negative, mycobacteria and brucella
31
Which organisms cause infectious tenosynovitis?
- Staph aureus and strep
- Chronic infections due to mycobacteria and fungi
- Disseminated gonococcal infection
32
How does infectious tenosynovitis present?
- Erythematous fusiform swellling of the finger
- Finger held in semiflexed position
- Tenderness over the length of the tendon sheet and pain with extension of the finger
33
How is infectious tenosynovitis treated?
- Empiric antibiotics
| - Hand surgeon review ASAP
34
Which organisms cause toxin mediated syndromes?
- Staph aureus
| - Strep pyogenes
35
What are the diagnostic criteria for staph TSS?
- Fever
- Hypotension
- Diffuse macular rash
- Three of the following organs involved: liver, blood, renal, GI, CNS and muscular
- Isolation of staph aureus from mucosal or normally sterile sites
- Production of TSSTq
- Development of antibody to toxin
36
What additional treatment does strep TSS need?
Urgent surgical debridement of the infected tissues
37
How is TSS treated?
- Remove offending agent
- IV fluids
- Inotropes
- Antibiotics
- IV immunoglobulins
38
What are the features of staph scalded skin syndrome?
- Infection by staph
- Widespread bullae and skin exfoliation
- Usually in children
39
How is scalded skin syndrome treated?
- IV fluids
| - Antimicrobials
40
What does the panton valentine leucocidin toxin cause and how is it treated?
- SSTI and haemorrhagic pneumonia
- Recurrent boils that are difficult to treat
- Treated with antibiotics
41
Which organism most commonly causes intravenous catheter associated infections?
Staph aureus (MSSA and MRSA)
42
How are intravenous catheter associated infections diagnosed and how are they treated?
- Clinically or positive blood cultures
- Remove cannular
- Express any pus
- Antibiotics for 14 days
- ECHO
43
How can IV catheter infections be prevented?
- Remove unsued cannulas
- Only insert cannulas when in use
- Change cannulae every 72hrs
- Monitor for thrombophlebitis
- Aseptic technique for insertion
44
How are surgical wounds classified?
- Class 1: clean wound (resp, GI, genital and urinary systems not entered)
- Class 2: clean contaminated wound (above tracts entered but no unusual contamination
- Class 3: contaminated wound
- Class 4: infected wound
45
Which organisms cause surgical site infections?
- Staph aureus
- Coagulase negative staph
- Enterococci
- E coli
- Pseudomonas
- Enterobacter
- Strep
- Fungi
- Anaerobes
46
What are the risk factors for surgical site infections?
- Diabetes
- Smoking
- Obesity
- Malnutrition
- Concurrent steroid use
- Colonisation with staph aureus
- Shaving of site night prior
- Improper skin prep
- Improper antimicrobial prophylaxis
- Break in sterile technique
- Inadequate theatre ventilation
- Perioperative hypoxia
47
How can surgical site infections be diagnosed and how are they treated?
- Pus/infected tissue for cultures (deep swabs)
| - Antibiotics to target likely organisms
