Skin and Soft Tissue Infections Flashcards
(104 cards)
1
Q
RECAP- what are the layers of the skin?
A
Epidermis
Dermis
Subcutaneous fat
Fascia
Muscle
2
Q
Impetigo?
A
Superficial skin infection
3
Q
What sign is highly indicative of impetigo?
A
Golden crust
4
Q
What is impetigo most commonly due to?
A
Staph. aureus infection
5
Q
In which age group in impetigo more common?
A
Children aged 2-5
->it is highly infective so can be passed on at nursery
6
Q
Which parts of the body does impetigo usually effect?
A
Exposed parts of the body e.g. face, extremities and scalp
7
Q
What are some predisposing factors for impetigo?
A
Skin abrasions
Minor trauma
Burns
Poor hygiene
Insect bites
Chickenpox
Eczema
Atopic dermatitis
8
Q
What is the treatment of impetigo?
A
Small area- topical antibiotics
Large area- topical treatment and oral antibiotics e.g. flucloxacillin
9
Q
Erysipelas?
A
Infection of the upper dermis
10
Q
How does erysipelas present?
A
Painful red area with no central clearing
Associated fever
Typically elevated borders
Regional lymphadenopathy (swelling of lymph nodes)
11
Q
What organism is usually the cause of erysipelas?
A
Strep. pyogenes
12
Q
Where does erysipelas usually effect?
A
Lower limbs
Areas of pre-existing lymphoedema, venous stasis, obesity, paraparesis and diabetes
->high reoccurrence rate, with 30% getting reoccurrence within 3yrs
13
Q
Where does cellulitis infect?
A
Deep dermis and subcutaneous fat
14
Q
How does cellulitis present?
A
Spreading erythematous area with no distinct borders
15
Q
Which organisms are most likely to cause cellulitia?
A
Strep. pyogenes
Staph. aureus
16
Q
What is the most common skin infection?
A
Cellulitis
17
Q
What symptom is common in cellulitis?
A
Fever
18
Q
Which blood related issue can cellulitis be the source of?
A
Bacteraemia
19
Q
What are some predisposing factors for cellulitis?
A
Diabetes
Tinea pedis- athlete’s foot
Lymphoedema
20
Q
What are some features of cellulitis?
A
Fever
Lymphangitis and/or lymphadenitis
21
Q
What is the treatment for erysipelas and cellulitis?
A
Combination of anti-staphylococcal and anti-streptococcal antibiotics
->extensive cases may require admission for IV antibiotics and rest
22
Q
Name three hair associated infections.
A
Folliculitis
Furunculosis
Carbuncles
23
Q
Folliculitis?
A
Circumcised pustular infection of a single hair follicle
24
Q
Furuncle?
A
Red, tender nodule surrounding a hair follicle with one draining point
25
Carbuncle?
Deep follicular abscess with several drainage points
26
How does folliculitis present?
Small red papules
Typically found on head, back, buttocks and extremities
27
What is the most common causative organism of folliculitis?
Staph.aureus
28
What are furuncles commonly referred to as?
Boils
29
Which layers of the skin is affected by furunculosis?
Dermis and subcutaneous fat
30
Which areas of the body does furunculosis usually affect?
Moist, hairy, friction prone areas e.g. face, axilla, neck and buttocks
31
What is the most common causative organism of furunculosis?
Staph.aureus
32
Are systemic symptoms common is furunculosis?
No
33
What are some of the risk factors for furunculosis?
Obesity
Diabetes
Atopic dermatitis
CKD
Corticosteroid use
34
To make sure you were paying attention, use of which drug can increase risks of furunculosis?
Corticosteroids
35
When does a carbuncle occur?
When infection spreads to involve multiple furuncles
36
Where would a carbuncle often be located?
Back of neck
Posterior trunk or thigh
37
What type of abscess is a carbuncle?
Multiseptated abscess
->pus may be expressed from multiple sites
38
What is the management of carbuncle?
Usually requires hospital admission as patients often unwell
Surgery and IV antibiotics required
39
What is the treatment of folliculitis?
No treatment required
40
What is the treatment of furunculosis?
If not improving, oral antibiotics
41
Which condition is one of the infectious disease emergencies relating to skin?
Necrotising fasciitis
42
What are some of the predisposing conditions which increase risks of necrotising fascitis?
Diabetes
Surgery
Trauma
Peripheral vascular disease
Skin popping- something to do w drugs, not picking dw gal
43
There are two types of necrotising fasciitis. What does type 1 refer to?
Mixed aerobic and anaerobic infection
44
List some of the typical organisms associated with necrotising fasciitis.
Streptococci
Staphylococci
Enterococci
Gram negative bacilli
Clostridium
45
Type 2 necrotising fasciitis is usually monomicrobial.
Which organism is it usually associated with?
Strep.pyogenes
46
What is the presentation of necrotising fasciitis?
Rapid onset
Development of erythema, extensive oedema and severe, unremitting pain
47
What are some signs of necrotising fasciitis which may develop?
Haemorrhagic bullae
Skin necrosis
Crepitus
48
What are some of the systemic features of necrotising fasciitis?
Fever
Hypotension
Tachycardia
Delirium
Multiorgan failure
49
Pyomyositis?
Purulent infection deep within striated muscle
Often secondary to seeding in damaged muscle
50
How does pyomyositis often manifest?
Often manifests as an abscess
51
What are some of the common sites of pyomyositis?
Thigh
Calf
Arms
Gluteal region
Chest wall
Psoas muscle
52
How can pyomyositis present?
Fever, pain, woody induration of affected muscle
53
If pyomyositis is left untreated, what can it lead to?
Septic shock and death
54
What are some of the predisposing factors for pyomyositis?
Diabetes
HIV/immunocompromised
IVDU
Rheumatological disease
Malignancy
Liver cirrhosis
55
What is the commonest cause of pyomyositis?
Staph aureus
56
Which investigations are used in pyomyositis?
CT/MRI
57
What is the treatment of pyomyositis?
Drainage with antibiotic cover depending on gram stain and culture results
58
Bursae?
Small sac-like cavities that contain fluid and are lined by synovial membrane
They facilitate movement and prevent friction
59
Where are bursae found?
Between bony prominences or tendons
60
What often causes septic bursitis?
Trauma
61
Where are the most common sites of septic bursitis?
Patellar
Olecranon
62
How does infection cause septic bursitis?
Infection usually spreads from adjacent skin infection
63
What are some predisposing factors to septic bursae?
Rheumatoid arthritis
Diabetes
Alcoholism
IVDU
Immunosuppression
Renal insufficiency
64
What are some of the features of septic bursitis?
Peritbursal cellulitis. swelling and warmth
Fever
Pain on movement
65
What is septic bursitis most commonly caused by in terms of organism?
Staph aureus
66
How is a diagnosis of septic bursitis made?
Aspiration of fluid
67
Infectious tenosynovitis?
Infection of the synovial sheaths that surround tendons
68
Which tendons are most often involved in infectious tensosynovitis?
Flexor muscle associated tendons
Tendon heaths of hand
69
Which organisms are the most common cause of infective tenosynovitis?>
Staph aureus
Streptococci
70
How does infectious tenosynovitis present?
Erythematous fusiform swelling of the finger
71
What are the features of infectious tenosynovitis?
Finger is held in a semiflexed position
Tenderness over the length of tendon sheath
Pain with extension of finger
72
What is the management of infectious tenosynovitis?
Empiric antibiotics
Need a hand surgeon to review ASAP
73
What are toxin-mediated syndromes usually because of?
Superantigens
->Superantigens are a class of immunostimulatory molecules produced by bacteria and viruses.
74
What happens in toxic-mediated syndromes?
Massive burst in cytokine release
Leads to endothelial leakage, haemodynamic shock and multi-organ failure and even death
75
Give some examples of toxin-mediated syndromes caused by staph.aureus.
TSST1
ETA and ETB
76
Give some examples of toxin-mediated syndromes caused by strep pyogenes.
TSST1
77
What can cause toxic shock syndrome?
Leaving in a tampon for too long
Can be due to small skin infections due to staph aureus secreting TSST1
78
What is the diagnostic criteria for staphylococcal TTS?
Fever
Hypotension
Diffuse macular rash
Three of the following organs involved : liver, blood, renal. GI, CNS, muscular
79
What is streptococcal TSS usually always associated with?
Presence of streptococci in deep seated infections e.g. erysipelas or necrotising fasciitis
80
Which has a higher mortality rate; staphylococcal TTS or streptococcal TTS?
Streptococcal
50% mortality rate compared to 5%
81
What is the treatment of streptococcal TTS?
Urgent surgical debridement of infected tissue
82
What is the general treatment of TTS?
Removal of offending agent e.g. tampon
IV fluids
Inotropes
Antibiotics
IV immunoglobulins
83
Staphylococcal scalded skin syndrome?
Infection due to a particular strain of staph aureus producing the exfoliative toxin A or B
84
Who is usually affected by staphylococcal scalded skin syndrome?
Children
85
What is staphylococcal scalded skin syndrome characterised by?
Widespread bullae and skin exfoliation
86
What is the treatment of staphylococcal scalded skin syndrome?
IV fluids
Antimicrobials
87
What can Panton-Valentine leucocidin toxin cause?
SSTI- skin and soft tissue injuries
Haemorrhagic pneumonia
88
Who is usually affected by Panton-Valentine leucocidin toxin?
Children and young adults
89
How do patients with Panton-Valentine leucocidin toxin present?
Recurrent boils which are difficult to treat
90
A teenager presents consistently with boils which are not responding to usual treatment.
What is the likely diagnosis?
Panton-Valentine leucocidin toxin
91
What is the treatment of Panton-Valentine leucocidin toxin?
Antibiotics which reduce the production of toxins
92
IV catheter associated infections usually start as a local skin or soft tissue inflammation but what can they progress to?
Cellulitis or even tissue necrosis
93
What are the risk factors for IV-catheter infections?
Continuous infusion >24hrs
Canula in situ >72 hrs
Cannula in lower limbs
Patients with neurological/neurosurgical problems
->lecturer said to never do a cannula in the lower limb
94
What is the most common organisms responsible for IV-catheter associated infections?
Staph aureus
95
What is the treatment of IV-catheter associated infections?
Remove cannula
Express any pus from the thrombophlebitis
Antibiotics for 14 days
ECHO
->prevention more important than treatment so do not leave cannula in if unused, for over 72hrs or don't use them if you don't need to
96
There are four classes of surgical site infections.
What is meant by class I?
Clean wound - resp, alimentary, genital or infected urinary systems not entered
97
There are four classes of surgical site infections.
What is meant by class II?
Clean-contaminated wound (previously mentioned tracts entered but no unusual contamination)
98
There are four classes of surgical site infections.
What is meant by class III?
Contaminated wound
Open, fresh accidental wounds or spillage from GIT
99
There are four classes of surgical site infections.
What is meant by class IV?
Infected wound
->infection present before operation
100
List some risk factors for surgical site infections.
Smoking
Diabetes
Obesity
Malnutrition
Concurrent steroid use
Colonisation w Staph aureus
101
What are some of the procedural factors which can increase risks of surgical site infections?
Shaving of site the night before
Improper preoperative skin prep
Improper antimicrobial skin prophylaxis
Break in sterile technique
Perioperative hypoxia
102
How is a diagnosis of a surgical site infection made?
Sending pus/infected tissue for cultures
Deep structure swabs
103
What is the treatment of surgical site infections?
Antibiotics to target the likely causative organisms
104
