Skin and Soft tissue infections Flashcards
what is impetigo?
superficial skin infection, presents with multiple vesicular lesions on an erythematous base and has a golden crust, common on face, extremities and scalp
Common cause of impetigo?
staph aureus, strep pyogenes (less common)
Risk factors of impetigo?
2-5 years, skin abrasions, minor trauma, burns, poor hygiene, insect bites, chickenpox, eczema, atopic dermatitis
Treatment of impetigo?
topical antibiotics (sometimes + oral)
what is erysipelas?
infection of the upper dermis,
red and painful area + fever and regional lymphadenopathy and lymphangitis,
has distinct elevated borders
what commonly causes erysipelas?
strep pyogenes
risk factors of erysipelas?
areas of pre-existing lymphoedema, venous stasis, obesity, paraparesis, dm
what is cellulitis?
skin infection involving deep dermis and subcutaneous fat,
spreading erythematous area with no distinct borders,
fever, regional lymphadenopathy and lymphangitis present
predisposing factors of cellulitis?
diabetes mellitus,
tinea pedis,
lymphoedema,
lymphangitis
Most likely organisms that causes cellulitis
strep pyogenes,
staph aureus
treatment of erysipelas and cellulitis
flucloxacillin
what is the most common organism causing folliculitis
staph aureus
what is furunculosis?
single hair-follicle-associated inflammatory nodule,
extends into dermis and subcutaneous tissue,
usually affects face, axilla, neck, buttocks
furunculosis causative organism?
staph aureus
furunculosis risk factors?
obesity, dm, atopic dermatitis, chronic kidney disease, corticosteroid uses
what is a carbuncle?
infection extends to involve multiple furuncles,
back of neck, posterior trunk or thigh,
purulent material expressed
carbuncle treatment?
iv antibiotics
predisposinf conditions to necrotising fasciitis
dm, surgery, trauma, peripheral vascular disease, skin popping
what is type 1 necrotising fasciitis
mixed aerobic and anaerobic infection
typical organisms causing type 1 necrotising fasciitis
streptococci, staphylococci, enterococci, gram -ve bacilli, clostridium
typical organisms causing type2 necrotising fasciitis
strep pyogenes
necrotising fasciitis presentation
erythema, extensive oedema, severe pain, haemorrhagic bullae, skin necrosis, crepitus, fever, hypotension, tachycardia, delirium, mutiorgan failure
treatment of necrotising fasciitis
surgical review,
broad spectrum antibiotics (flucloxacillin, gentamicin, clindamycin)
what is pyomyositis?
purulent infection deep within striated muscle,
manifests as an abscess
common sites of pymyositis?
thigh, calf, arms, gluteal region, chest wall, psoas muscle
presentation of pyomyositis?
fever,
pain,
woody induration of affected muscle
predisposing factors of pyomyositis
dm, HIV/ immunocompromised, IDU, rheumatological diseases, malignancy, liver cirrhosis
common cause of pyomyositis
staph aureus
pyomyositis investigations?
CT/ MRI,
gram stain
treatment of pyomyositis
drainage and antibiotic cover
predisposing factors for septic bursitis
rheumatoid arthritis, alcoholism, DM, IDU, immunosuppresion, renal insufficiency
presentation of septic bursitis?
peribursal cellulitis, swelling, warmth, fever, pain on movement
Diagnosis of septic bursitis
aspiration of fluid,
common cause is staph aureus
what is infectious tenosynovitis
infection of the synovial sheats that surround tendons
common cause of infectious tenosynovitis?
staph aureus and stretococci,
penetrating trauma most commonly incites event
presentation of infectious tenosynovitis?
erythematous fusiform swelling of finger,
held in semiflexed position,
tenderness over tendon sheat,
pain on extension
treatment of infectious tenosynovitis?
empiric antibiotics,
hand surgeon
diagnostic criteria for staphylococcal toxic shock syndrome?
fever,
hypotension,
diffuse macular rash,
3 of following organs involved- liver, blood, renal, gi, cns, muscular,
isolation of staph aureus form mucosal or normally sterile site,
production of TSST1 by isolate,
development of antibody to toxin
treatment of toxic shock syndrome?
remove offending agent, IV fluids, inotropes, antibiotics, IV immunoglobulins
what is panton-valentine leucocidin toxin?
gamma haemolysin,
can cause SSTI and haemorrhagic pneumonia,
presents with recurrent boils
risk factors for IV-catheter associated infections?
continuous infusion >24 hours,
cannula in situ >72 hours,
cannula in lower limb,
patients with neurological/ neurosurgical problems
Cause of IV-catheter associated infections
staph aureus,
forms biofilm which spills into bloodstream
treatment of IV-catheter associated infections
remove cannula,
express any pus from thrombophlebitis,
antibiotics for 14 days,
echocardiogram
class 1 of surgical site infections?
clean wound
class 2 of surgical site infections?
clean-contaminated wound
class 3 of surgical site infections?
contaminated wound
class 4 of surgical site infections?
infected wound
procedural risk factors for surgical site infections?
shaving of site night prior to procedure, improper preoperative skin preparation, improper antimicrobial prophylaxis, back in sterile technique, inadequate theatre ventilation, perioperative hypoxia
