13. Skin and soft tissue infections Flashcards
Who gets skin and soft tissue infections?
Diabetes leading to neuropathy and vasculopathy
Immunosuppresion
Renal failure
Milroy’s disease
Predisposing ski diseases (atopic dermatitis)
What else is important is good to consider
Site of infection and potential complications
Drug resistant strains? (MRSA)
Drug interactions
Drug allergies
What organism is very common for skin and soft tissue infections?
Staph Aureaus
What is impetigo?
Superfifical skin infection, highly infectious and common in children 2-5 years old.
How does impetigo present?
Ususally occurs on expose parts of the boies such as face, extremities and scalp.
Multiple vesicluar lesions n an erythematous base
Golden crust is highly suggestive of this diagnosis
Most commonly due to staph aureus
What are predisposing factors to impetigo?
Skin abrasions Minor trauma Burns Poor hygiene Insect bites Chickenpox Eczema Atopic dermatitis
What is the treatment of impetigo?
small areas of infection- topical antibiotics
Large areas of infections- oral antibiotics e.g. flucloxacillin
What is erysipelas?
Infection of the upper dermis. 70-80% is found on the lower limbs. there is a high recurrence rate
How does erysipelas present?
Red, bubbly stretched skin,
associated fever
regional lymphadenopathy and lmyphangitis
elevated borders, typically cuased by strep pyogenes
What are predisposing factors to erysipelas?
Lymphoedema venous stasis obesity paraparesis diabetes
What is cellulitis
Diffuse skin infection involving deep dermis and subcutaneous fat
How does cellulitis present
spreading erythematous area with no distinct borders
Fever is common
Regional lymphadenopathy and lymphangitis
Possible of bactearemia
Staph aureus and strep pyogenes most common organisms
What are predisposing factors to cellulitis?
Diabetes
Tinea pedis (athletes foot)
Lymphoedema
How do you treat erysipelas and cellulitis?
Combination of anti staph and anti strep antibiotics
In extensive disease admit and treat with IV antibiotics and rest
What are the three follicle associated infections?
Folliculitis- single follicle involvement
Furuculosis- red, tender nodule surrounding a follicle with one draining point)
Carbuncles- deep abscess of several follicles with several draining points
What is folliculitus?
Circumscribed pustular infection of a hair follicle
How does folliculitis present?
Presents as small red papules
Central area of purulence that may rupture and drain
Most common organsism is staph aureus, not serious
What is furinculosis?
Furuncles commonly referred to as boils
Single hair nodule associate inflammatory nodules
How does furinculosis present?
Usually swelling ad redness on areas in the face,axilla, neck, buttocks. Staph aureus is the most common organism but systemic symptoms are uncommon. Mo treatment often required
What are the risk factors for furunculosis?
Obesity Diabetes Atopic dermatitis Chronic kidney disease Corticosteroid use
What are carbuncle’s?
Infections that involve multiple furuncles.
How do carbuncle’s present?
Often in back of neck, posterior trunk or thigh
Multiseptated abscesses
Purulent material may be expressed from multiple sites
Constitutional symptoms may be common
How do you treat carbuncle’s?
Often require admission to hospital, surgery and IV antibiotics
What is necrotising fasciitis?
An emergency of infectious disease, skin eating bacteria affecting any site in the body
What organsisms cause necrotising fasciitis?
Streptococci Staphylococci Enterococci Gram negative bacilli Clostridium
What predisposes people to necrotitsing fasciitis?
Diabetes mellitus Surgery Trauma Peripheral vascular disease Skin popping- injecting IV drugs but missing the vein
What are the different types of necrotising fasciitis?
Type 1- mixed aerobic and anaerobic infection
Type II- monomicrobial, typically associated with strep pyogenes. Fast onset, sepsis comes on very quick.
How does necrotising fasciitis present?
Rapid onset, unremitting pain, oedema, erythema
Heamorrhagic bullae, skin necorsis, crepitus
Systemic features e.g. fever, hypotension, tachycardia, delirium and multiorgam failure.
Parastesthia at site of infection points towards
How do you treat Necrotising fasciitis?
Surgical review is mandatory, imaging may help but can delay treatment
Broad spectrum antibiotics- flucloxacillin, Gentamicin, clindamycin
Overall mortality high
What is pyomyosisits?
Purulent infection deep within skeletal muscle often manifesting as an abscess
How does it present?
fever, pain or woody muscle (pushing on muscle feels like pushing on wood)
If untreated leads to septic shock and death
infection often to damage to the msucele.
Common sites include:
Thigh
Calf
Arms
Glutes
Chest wall
Psoas muscle
Commonest cause is staph aureus
How do you treat pyomyosistis?
Investigate using CT/MRI
Drainage with antibiotics cover depending on stain and culture results
How do you treat pyomyosistis?
Investigate using CT/MRI
Drainage with antibiotics cover depending on stain and culture results
What is septic bursistis?
Infection of te small sac like cavities that are lined by synovial membrane.
How doe septic bursitis present?`
Infection is often from adjacent skin infection.
Peribursal cellulitis, swelling and warmth are common
Fever and pain on movement are also seen
Commonest cause is staph aureus
What are the predisposing factors to bursitis?
RA Alcoholism Diabetes IV drug abuse Immunosupression Renal insufficiency
What is the treatment of septic bursitis?
Diagnosis is based on aspiration of the fluid
Treat with antibiotics
What is infectious tenosynovitis
Infection of the synovial sheaths that surround tendons
How does infected tenosynovitis present
Flexor muscle associated especially in the hands
Penetrating trauma the most inciting event
Muscle will be in a semiflexed position
Tenderness over length of sheath and pain on extension
Most common cause is staph aureus
How do you treat infected tenosynovitis?
Empircal antibiotcs and get the surgeons involved
What are toxin mediated syndromes?
Often due to sueprantigens, group of pyrogenic atigens
Actvivate vast amount sof T cells causing endothelial leakage, haemodynamix hock, multiorgan failure adn eath
Mostly staph aureus and strep. pyogenes
What is toxic shock syndrome?
Can be due to small skin infections are the use of high absorbency tampons
How does toxic shock syndrome present?
Fever, hypotension, diffuse macular rash
3/6 involved- Liver, blood, renal GI, CNS, MSK
TSST1 is produced and induces antibody toxin
How do you treat toxic shock syndrome?
Remove offending agent Intravenous fluids Inotropes Antibiotics Intravenous immunoglobulins
What is staphylococcal scalded skin syndrome?
Infection due to a particular strain of staph aureus producing exfoliative toxin A or B
How does staphylococcal scalded syndrome present?
Characterised by widespread bullae and skin exfoliation
Usually occurs in children but rarely in adults
Treat with IV fluids and antibiotics
What are intravenous catheter associated infections?
What they say on the tin
How do intravenous catheter associated infections present?
local SST inflammation leading to cellulitis, common to have bacteraemia
Most common agents are MSSA and MRSA
Commonly form a biofilm which spills into the bloodstream
Can seed into other places e.g. endocarditis, osteomyetits
Hwo do you treat intravenous catheter associated infections?
Remove cannula
Express any pus from the thrombophlebitis
Antibiotics for 14 days
Echcardiogram
How do you prevent IV catheter associated infections
Do not leave unused cannulae
Do not insert cannulae unless yo are using them
Change cannulae every 72 hours
Monitor for thrombophlebitis
Use aseptic technique when inserting cannulae
What are the classifications of surgical wounds?
Class I- clean wound
Class II- clean-contaminated wound- tracts entered but no unusual contamination
Class III- contaminated wound
Class IV- infected wound
What are risk factors for surgical wounds becoming infected?
Diabetes, smoking obesity malnutrition concurrent steroid use colonisation with staph aureus Shaving night before break in sterile techniquw perioperative hypoxia
How do you diagnose surgical wound infections?
Avoid superfificla swabs, aim for dee structures and send cultures away
Consider an unlikely pathogen if obtained rom sterile site e.g. bone
Antibiotics to target organsim
