Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Infectious disease > Skin and soft tissue infections > Flashcards

Skin and soft tissue infections Flashcards

1
Q

What things should be concidered when a patient has a skin or soft tissue infection?

A 
○ Site
- Possible complications with specific sites (ex; abdominal, face)
○ Organism
○ Host 
- Diabetes leading to neuropathy and vasculopathy
- Immunosuppression
- Renal failure
- Milroy’s disease
- Predisposing skin conditions (ex; atopic dermatitis) 
○ Environment
- Drug-resistant strains (MRSA)
- Drug interactions
- Drug allergies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is impetigo?

A

○ Superficial skin infection
○ Multiple vesicular lesions on an erythematous base
○ Golden crust is highly suggestive of this diagnosis
- Forms on the face and arms of children
- Normally doesn’t give systemic effects
○ Most commonly due to Staph aureus
○ Less commonly Strep pyogenes
○ Common in children 2-5 years of age
○ Highly infectious
○ Usually occurs on exposed parts of the body including face, extremities and scalp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the predicposing factors of impetigo?

A
  • Skin abrasions
  • Minor trauma
  • Burns
  • Poor hygiene
  • Insect bites
  • Eczema
  • Atopic dermatitis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the treatment of impetigo?

A
  • Small areas can be treated with topical antibiotics alone

- Large areas need topical treatment and oral antibiotics (e.g. flucloxacillin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is erysipealas

A

○ Infection of the upper dermis
○ May involve intact skin
○ High recurrence rate (30% within 3 years)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the clinical features of erysipealas?

A

○ Painful, red area (no central clearing)
○ Associated fever
○ Regional lymphadenopathy and lymphangitis
○ Typically has distinct elevated borders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the most comon cause of erysipealis?

A

Strep. pyogenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where does erysipealis occur?

A

○ 70-80% of cases involves the lower limbs
○ 5-20% affect the face
○ Tends to occur in areas of pre-existing lymphoedema, venous stasis, obesity, paraparesis, diabetes mellitus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is cellulits?

A

Diffuse skin infection involving deep dermis and subcutaneous fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the clinical features of cellulitis?

A

○ Presents as a spreading erythematous area with no distinct borders
○ Fever is common
○ Regional lymphadenopathy and lymphangitis
○ Possible source of bacteraemia
○ Patients can have lymphangitis and/or lymphadenitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are th predisposing factors of cellulitis

A
  • Diabetes mellitus
  • Tinea pedis
  • Lymphoedema
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What causes cellulits?

A

○ Most likely organisms are Strep pyogenes and Staph aureus

○ Remember role of Gram negatives in diabetics and febrile neutropaenics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the treatment for erysipealis and cellulitis?

A

○ A combination of anti-staphylococcal and anti-streptococcal antibiotics
○ In extensive disease, admission for intravenous antibiotics and rest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is folliculitis?

A

○ Circumscribed, pustular infection of a hair follicle
○ Up to 5mm in diameter
○ Present as small red papules
○ Central area of purulence that may rupture and drain
○ Typically found on head, back, buttocks and extremities
○ It can infect adjuvant follicles if not treated
○ Benign condition
○ Constitutional symptoms not often seen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the most common cause of folliculitis ?

A

Staph aureus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are furuncosis?

A

○ Furuncles commonly referred as boils
○ Single hair follicle-associated inflammatory nodule
○ Extending into dermis and subcutaneous tissue
○ Usually affected moist, hairy, friction-prone areas of body (face, axilla, neck, buttocks)
○ May spontaneously drain purulent material
○ Systemic symptoms uncommon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the most common cause of furuncosis?

A

Staph. aureus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the risk factors for furuncosis?

A
  • Obesity
  • Diabetes mellitus
  • Atopic dermatitis
  • Chronic kidney disease
  • Corticosteroid use
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is a carbuncle?

A

○ Occurs when infection extends to involve multiple furuncles
○ Often located back of neck, posterior trunk or thigh
○ Multiseptated abscesses
○ Purulent material may be expressed from multiple sites
○ Constitutional symptoms common
○ A normal healthy patient shouldn’t get this, so look for underlying causes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the treatment for hair associated infections?

A

○ With folliculitis, no treatment or topical antibiotics
○ With furunculosis, no treatment or topical antibiotics. If not improving oral antibiotics might be necessary
○ Carbuncles often require admission to hosiptal, surgery and intravenous antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is necrotosing fasciitis?

A

○ One of the infectious diseases emergencies

○ Any site may be affected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the predisposing factors of necrotosing fasciitis?

A
  • Diabetes mellitus
  • Surgery
  • Trauma
  • Peripheral vascular disease
  • Skin popping
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is type 1 necrotosing fasciitis?

A

Refers to a mixed aerobic and anaerobic infection (diabetic foot infection, Fournier’s gangrene)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the typical organisms that cause type 1 necrotosing fasciitis?

A 
□ Streptococci
□ Staphylococci
□ Enterococci
□ Gram negative bacilli
□ Clostridium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is type 2 necrotising fasciitis (and what causes it)?

A
  • Monomicrobial

- Normally associated with Strep. pyogenes

26
Q

What are the clinical features of necrotising fasciitis?

A
  • Rapid onset
  • Sequential development of erythema, extensive oedema and severe, unremitting pain
  • Haemorrhagic bullae, skin necrosis and crepitus may develop
  • Systemic features include fever, hypotension, tachycardia, delirium and multiorgan failure
  • Anaesthesia at site of infection is highly suggestive of this disease
27
Q

How is necrotising fasciitis managed?

A
  • Surgical review is mandatory
  • Imaging may help but could delay treatment
  • Antibiotics should be broad spectrum
    □ Flucloxacillin
    □ Gentamicin
    □ Clindamycin
28
Q

What is the mortality of necrotising fasciitis?

A
  • Overall mortality ranges between 17-40%
29
Q

What is pyomyositis?

A

○ Purulent infection deep within striated muscle, often manifesting as an abscess
○ Infection is often secondary to seeding into damaged muscle
○ Multiple sites involved in 15%

30
Q

What are the common sites for pyomyositis?

A
  • Thigh
  • Calf
  • Arms
  • Gluteal region
  • Chest wall
  • Psoas muscle
31
Q

What are the clinical features of pyomyositis?

A
  • Can present with fever, pain and woody induration of affected muscle
  • If untreated can lead to septic shock and death
32
Q

What are the predisposing factors of pyomyositis?

A 
□ Diabetes mellitus
□ HIV/immunocompromised
□ Intravenous drug use
□ Rheumatological diseases
□ Malignancy
□ Liver cirrhosis
33
Q

What are the causes of pyomyositis?

A
  • Commonest cause is Staph aureus

- Other organisms can be involved including Gram positive/negatives, TB and fungi

34
Q

How is pyomyositis managed?

A
  • Investigation using CT/MRI

- Treatment is drainage with antibiotic cover depending on Gram stain and culture results

35
Q

What are the predisposing factors od septic bursitis?

A
  • Infection is often from adjacent skin infection
  • Other predisposing factors include
    □ Rheumatoid arthritis
    □ Alcoholism
    □ Diabetes mellitus
    □ Intravenous drug abuse
    □ Immunosuppression
    □ Renal insufficiency
36
Q

What are the clinical features of septic bursitis?

A
  • Peribursal cellulitis, swelling and warmth are common
  • Fever and pain on movement also seen
  • Diagnosis is based on aspiration of the fluid
37
Q

What causes septic bursitis?

A
  • Most common cause is Staph aureus
  • Rarer organisms include
    □ Gram negatives
    □ Mycobacteria
    □ Brucella
38
Q

What is infectious tenosynovitis?

A

○ Infection of the synovial sheaths that surround tendons
○ Flexor muscle-associated tendons and tendon sheaths of the hand most commonly involved
○ Penetrating trauma most common inciting event

39
Q

What causes infectious tenosynovitis?

A

○ Most common cause Staph aureus and streptococci
○ Chronic infections due to mycobacteria, fungi
○ Possibility of disseminated gonococcal infection

40
Q

What is the clinical presentation of tenosynovitis?

A
  • Present with erythematous fusiform swelling of finger
  • Held in a semiflexed position
  • Tenderness over the length of the tendon sheath and pain with extension of finger are classical
41
Q

How is infectious tenosynovitis managed?

A
  • Empiric antibiotics

- Hand surgeon to review ASAP

42
Q

What are toxic mediated syndromes?

A

○ Often due to superantigens
○ Group of pyrogenic exotoxins
○ Do not activate immune system via normal contact between APC and T cells
○ Superantigens bypass this and attach directly to the T cell receptors activating up to 20% of the total pool of T cells instead of the normal 1/10,000
○ Massive burst in cytokine release
○ Leads to endothelial leakage, haemodynamic shock, multi-organ failure and death

43
Q

What are the causes of toxic mediated syndromes?

A 
- Mostly due to some strains of Staphylococcus aureus and Streptococcus pyogenes
□ Staph aureus: 	
® TSST1
® ETA and ETB
□ Strep pyogenes:	
® TSST1
44
Q

What are the diagnostic criteria for staphylococcal TSS?

A
  • Fever
  • Hypotension
  • Diffuse macular rash
  • Three of the following organs involved
    □ Liver, blood, renal, gastrointestinal, CNS, muscular
  • Isolation of Staph aureus from mucosal or normally sterile sites
  • Production of TSST1 by isolate
  • Development of antibody to toxin during convalescence
45
Q

What is the mortality of sptretococcal TSS compared to staphylococcal TSS?

A

50% (strep)

5% (staph)

46
Q

What is the treatment of streptococcal associated TSS?

A 
-Treatment necessitates urgent surgical debridement of the infected tissues
□ Remove offending agent (e.g. tampon)
□ Intravenous fluids
□ Inotropes
□ Antibiotics
□ Intravenous immunoglobulins
47
Q

What is staphylococcal scalded skin syndrome?

A
  • Infection due to a particular strain of Staph aureus producing the exfoliative toxin A or B (ETA, ETB)
  • Characterised by widespread bullae and skin exfoliation
  • Usually occurs in children but rarely in adults as well
  • Treatment with intravenous fluids and antimicrobials
  • Mortality 3% in children but higher in adults who often are immunosuppressed
48
Q

What is penton-Valentine leucocidin toxin?

A
  • It is a gamma haemolysin
  • Can be transferred from one strain of Staph aureus to another, including MRSA
  • Can cause SSTI and haemorrhagic pneumonia
  • Tends to affect children and young adults
  • Patients present with recurrent boils which are difficult to treat
  • Treat with antibiotics that reduce toxin production
49
Q

What are the risk factors for intravenous-catheter associated infections?

A
  • Continuous infusion >24 hours
  • Cannula in situ >72 hours
  • Cannula in lower limb
  • Patients with neurological/neurosurgical problems
50
Q

What are the causes of intravenous-catheter associated infections?

A
  • Most common organism is Staph aureus (MSSA and MRSA)
  • Commonly forms a biofilm which then spills into bloodstream
  • Can seed into other places (e.g. endocarditis, osteomyelitis)
  • Diagnosis made clinically or by positive blood cultures
51
Q

How are intravenous-catheter associated infections managed?

A
  • Treatment is to remove cannula
  • Express any pus from the thrombophlebitis
  • Antibiotics for 14 days
  • Echocardiogram
52
Q

How are intravenous catheter associated infections prevented?

A

□ Do not leave unused cannula
□ Do not insert cannulae unless you are using them
□ Change cannulae every 72 hours
□ Monitor for thrombophlebitis
□ Use aseptic technique when inserting cannulae

53
Q

What does a class 1 surgical wound mean?

A

Clean wound (respiratory, alimentary, genital or infected urinary systems not entered)

54
Q

What does a class 2 surgical wound mean?

A

Clean-contaminated wound (above tracts entered but no unusual contamination)

55
Q

What does a class 3 surgical wound mean?

A

Contaminated wound (Open, fresh accidental wounds or gross spillage from the gastrointestinal tract)

56
Q

What does a class 4 surgical wound mean?

A

Infected wound (existing clinical infection, infection present before the operation)

57
Q

What are the causes of surgical wound infections?

A
  • Staph aureus (including MSSA and MRSA)
  • Coagulase negative Staphylococci
  • Enterococcus
  • Escherichia coli
  • Pseudomonas aeruginosa
  • Enterobacter
  • Streptococci
  • Fungi
  • Anaerobes
58
Q

What are the aetiologies of surgical wound infecion?

A
  • Diabetes
  • Smoking
  • Obesity
  • Malnutrition
  • Concurrent steroid use
  • Colonisation with Staph aureus
59
Q

What procedural factors can lead to surgical wound infections?

A
  • Shaving of site the night prior to procedure
  • Improper preoperative skin preparation
  • Improper antimicrobial prophylaxis
  • Break in sterile technique
  • Inadequate theatre ventilation
  • Perioperative hypoxia
60
Q

How are surgical wound infections diagnosed?

A
  • Importance of sending pus/infected tissue for cultures especially with clean wound infections
  • Avoid superficial swabs – aim for deep structures
  • Consider an unlikely pathogen as a cause if obtained from a sterile site (e.g. bone infection)
  • Antibiotics to target likely organisms

Infectious disease (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions