W07 - Clinical 2 - Skin & Soft Tissue, Fungal Infection

Question 1

Define skin and soft tissue infections

Answer 1

a variety of pathological conditions that involve the skin and underlying subcutaneous tissue, fascia, or muscle, ranging from simple superficial infections to severe necrotizing infections.

Question 2

List the most common infectious agents associated with these infections

Answer 2

S. aureus = IMPETIGO
S. aureus = PYOMYOSITIS

Strep pyogenes = ERYSIPELAS

Question 3

Describe the major risk factors for developing skin and soft tissue infections

Answer 3

DM, imm suppr., Ren.F., Milroy’s Disease, Atopic Dermatitis

Question 4

Understand how and why special patient groups have cutaneous infections whose causative agents are different from the normal population (especially diabetics and intravenous drug users)

Answer 4

a

Question 5

List the most important toxin-related syndromes affecting skin and soft tissues

Answer 5

caused by SUPERANTIGENS: pyrogenic exotoxins attach directly to T cell receptors = massive immune stimulation = cytokine storm

Question 6

Understand the importance of early diagnosis and management of toxin-related syndromes affecting skin and soft tissues

Answer 6

a

Question 7

Be able to recognise cannulae-associated infections, list the most important causes and possible complicatiosn

Answer 7

IV catheter, sepsis common complication

Question 8

Understand the importance of the different means of preventing infections in patients with peripheral venous cannulae

Answer 8

a

Question 9

List the various types of surgical wound infections

Answer 9

predisp = DM, smoking, obesity, malnutrition, steroid use, S aureus colonisation

=> send pus/tissue for culture

Question 10

Understand the most common causes of surgical wound infections with particular reference to MRSA

Answer 10

(commonly S. aureus; coag neg Staph., enterococcus, E. coli)

Question 11

IMPETIGO

Answer 11

multiple vesicular lesions w/ erythematous base, GOLDEN CRUST (staph aureus) = baked cheddar

exposed parts of skin = face, extremities, scalp

> topical abx for small areas
+oral abx = FLUCLOX larger areas

Question 12

ERYSIPELAS

Answer 12

(strep pyogenes)
upper dermis, painful red area + FEVER
regional lymphadenopathy and lymphangitis
*commonly lower limbs, next commonest FACE
* in areas of pre-existing lymphoedema, venous stasis, obesity, paraparesis, DM

elevated borders

Question 13

CELLULITIS

Answer 13

(Strep pyogenes, Staph aureus)

diffuse skin infection: deep dermis + subcutaneous fat
no borders, spreading eryth. area
* FEVER common
* regional lymphadenopathy

-DM, tinea pedis, lymphoedema

> combo of anti-staph and anti-strept abx
or IV (extensive)

Question 14

Milroy’s Disease

Answer 14

Milroy’s disease (MD) is a familial disease characterized by lymphedema, commonly in the legs, caused by congenital abnormalities in the lymphatic system. Disruption of the normal drainage of lymph leads to fluid accumulation and hypertrophy of soft tissues.

Question 15

Hair-associated Infections

Answer 15

FOLLICULITIS: circumscribed pustular infection, small red papules (staph aureus)

FURUNCULOSOS: single hair follicle inflamm nodule = boils. spont. drain.

CARBUNCLES: multiple furuncles (back, neck, thigh), multiseptated abscesses, purulent material
> hospital for IV abx

> otherwise nil treatment but TOPICAL ABX or oral (if not improving)

Question 16

Necrotising Fasciitis

Answer 16

predisp factors: DM, Sx, trauma, periph. Vasc dis., skin popping

-rapid onset
- erythem., extensive oedema, pain+++
+ fever, hypoT

Type 1 = mixed infection
- strept., staph., enterococci, gram -ve., clostridium

Type 2 = MONOMICROBIAL (strep pyogenes)

> broad abx = Fluclox. / Gentamicin / Clindamycin

Question 17

Pyomyositis

Answer 17

(s. aureus) or gram+ / gram-, TB, fungi

Purulent striated muscle = abscess
2º to dmg & infection
* thighs, calves, arms, gluteal region
- DM, HIV, IVDU, malignancy

• fever, pain => septic shock
• CT/MRI

> drainage, abx cover

Question 18

Septic bursitis

Answer 18

(S. aureus)
infection derived from adjacent skin injection
= sac cavities filled with fluid

predisp:

• IV drug abuse
• rheum arth.
• alcoholism
• DM
• imm supr
• R.Failure
• aspiration fluid = Dx

Question 19

Infectious tenosynovitis

Answer 19

Flexor muscle-associated tendons and tendon sheats of the hand most commonly involved
d/t penetrating trauma
= ERYTH. FUSIFORM SWELLING OF FINGER + tendon tenderness

(s. aureus, streptococci)
+ chronic infection d/t mycobact. fungi

> empiric abx
hand surgeon review

Question 20

Causes of Toxin-mediated syndromed

Answer 20

Staphylococcus aureus and Streptococcus pyogenes

S. aureus = TSST1, ETA, ETB

Strep pyogenes = TSST1

=

Question 21

Diagnostic criteria for Staphylococcal & Streptococcal TSS

Answer 21

STAPH

• Fever
• Hypotension
• Diffuse macular rash

STREPT
- associated w/ strep presence in deep infections (erysipelas or necrotising fasciitis)

> sx debridement
Fluids
abx
IV Ig

Question 22

Staphylococcal scalded skin syndrome

Answer 22

production of exfoliative toxin A or B
= widespread bullae, skin exfoliation

*children > adults

> Iv fluids, abx7

Question 23

IV catheter infections

Answer 23

progression to cellulitis or tissue necrosis + bacteraemia

S. aureus and MRSA = forms biofilm = blood = infective mets. (valves or bones)

> remove cannula
Abx 14d
ECHO

Question 24

Appreciate the burden of fungal infections from a global perspective

Answer 24

signfiicant amount of mild cases go undiagnosed

opportunistic

• immunodef.
• HIV/AIDS
• malignancy

chronic lung diseases: asthma, COPD, CF, Sarcoidosis

Question 25

Know the 3 fungal organisms causing the majority of invasive fungal infections in the UK/Europe

Answer 25

CANDIDASIS (yeast-like)
non-commensal. asymptomatic until disruption.

TINEA (dermatophytes)

ASPERGILLUS (mould)
- soil, and organic matter, damp buildings

Question 26

Understand the concept of invasive fungal infections classified as opportunistic infections

Answer 26

CANDIDIASIS

• vulnerable skin sites
• Vaginal thrush
• oral: furry tongue, plaques
• SYSTEMIC CANDIDA

> CLOTRIMAZOLE (topical) - vaginal
GLUCONAZOLE (oral) - vaginal

> NYSTATIN (topical) - oral thrush

ASPERGILLUS: common in ppl w/ underlying issues
• cough, SOB, wheeze, pyrexia, malaise, headache

• allergic bronchopulmonary aspergilliosis = ASTHMA and CF 3w cough => pulmonary fibrosis
• sputum culture

Question 27

Know which patient groups are affected by invasive fungal infections

Answer 27

• extremes of age
• imm compr.
• steroid users
• chronic diseases
• DM
• recent abdo sx (systemic)

Question 28

Know the 3 classes of antifungals available for treatment of invasive fungal infections

Answer 28

> antifungal topicals or orals

> steroids (allergic broncpulm aspergilliosis)

Question 29

Tinea

Answer 29

• scaly, itchy skin
• flat/raised annular patches, clear centre, asymmetrical distribution

> topical creams
oral for extensive

Question 30

When does pulmonary aspergilliosis become chronic

Answer 30

greater than 3 mos. exacerbations not responding to abx, resp symptoms

*cxr investigatio, sputum investigation

> oral anti-fungals

Question 31

Aspergilloma

Answer 31

Fungal mass developing in lung scar/abscess (from prev disease) - opportunistic in nature

• HAEMOPTYSIS*
• cough + fever
• or incidental CXR

predisp = TB, sarcoidosis, bronchiectasis, post-pulm infection, cyst or bullae,

• CT scan

> Sx, LT anti-fungal

Question 32

Significance of Acute Invasive Pulmonary Aspergilliosis

Answer 32

at risk: neutropenic patients

post-transplant

phagocytic defects

presentation:
cough, SOB, fever, haemoptysis, pleuritic chest pain, nasal congestion + pain (think sinusitis development)

also present as persistent febrile neutropenia
=> spread to kidney brain thyroid, GI, eye, skin

> IV anti-fungals