W07 - Clinical 2 - Skin & Soft Tissue, Fungal Infection Flashcards
Define skin and soft tissue infections
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.
List the most common infectious agents associated with these infections
S. aureus = IMPETIGO
S. aureus = PYOMYOSITIS
Strep pyogenes = ERYSIPELAS
Describe the major risk factors for developing skin and soft tissue infections
DM, imm suppr., Ren.F., Milroy’s Disease, Atopic Dermatitis
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)
a
List the most important toxin-related syndromes affecting skin and soft tissues
caused by SUPERANTIGENS: pyrogenic exotoxins attach directly to T cell receptors = massive immune stimulation = cytokine storm
Understand the importance of early diagnosis and management of toxin-related syndromes affecting skin and soft tissues
a
Be able to recognise cannulae-associated infections, list the most important causes and possible complicatiosn
IV catheter, sepsis common complication
Understand the importance of the different means of preventing infections in patients with peripheral venous cannulae
a
List the various types of surgical wound infections
predisp = DM, smoking, obesity, malnutrition, steroid use, S aureus colonisation
=> send pus/tissue for culture
Understand the most common causes of surgical wound infections with particular reference to MRSA
(commonly S. aureus; coag neg Staph., enterococcus, E. coli)
IMPETIGO
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
ERYSIPELAS
(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
CELLULITIS
(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)
Milroy’s Disease
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.
Hair-associated Infections
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)
Necrotising Fasciitis
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
Pyomyositis
(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
Septic bursitis
(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
Infectious tenosynovitis
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
Causes of Toxin-mediated syndromed
Staphylococcus aureus and Streptococcus pyogenes
S. aureus = TSST1, ETA, ETB
Strep pyogenes = TSST1
=
Diagnostic criteria for Staphylococcal & Streptococcal TSS
STAPH
- Fever
- Hypotension
- Diffuse macular rash
STREPT
- associated w/ strep presence in deep infections (erysipelas or necrotising fasciitis)
> sx debridement
Fluids
abx
IV Ig
Staphylococcal scalded skin syndrome
production of exfoliative toxin A or B
= widespread bullae, skin exfoliation
*children > adults
> Iv fluids, abx7
IV catheter infections
progression to cellulitis or tissue necrosis + bacteraemia
S. aureus and MRSA = forms biofilm = blood = infective mets. (valves or bones)
> remove cannula
Abx 14d
ECHO
Appreciate the burden of fungal infections from a global perspective
signfiicant amount of mild cases go undiagnosed
opportunistic
- immunodef.
- HIV/AIDS
- malignancy
chronic lung diseases: asthma, COPD, CF, Sarcoidosis
Know the 3 fungal organisms causing the majority of invasive fungal infections in the UK/Europe
CANDIDASIS (yeast-like)
non-commensal. asymptomatic until disruption.
TINEA (dermatophytes)
ASPERGILLUS (mould)
- soil, and organic matter, damp buildings
Understand the concept of invasive fungal infections classified as opportunistic infections
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
Know which patient groups are affected by invasive fungal infections
- extremes of age
- imm compr.
- steroid users
- chronic diseases
- DM
- recent abdo sx (systemic)
Know the 3 classes of antifungals available for treatment of invasive fungal infections
> antifungal topicals or orals
> steroids (allergic broncpulm aspergilliosis)
Tinea
- scaly, itchy skin
- flat/raised annular patches, clear centre, asymmetrical distribution
> topical creams
oral for extensive
When does pulmonary aspergilliosis become chronic
greater than 3 mos. exacerbations not responding to abx, resp symptoms
*cxr investigatio, sputum investigation
> oral anti-fungals
Aspergilloma
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
Significance of Acute Invasive Pulmonary Aspergilliosis
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
