Date post: | 24-May-2015 |
Category: |
Health & Medicine |
Upload: | sanjaya-weerasinghe |
View: | 1,031 times |
Download: | 4 times |
Skin and Soft Tissue Infections
Sanjaya Gihan Weerasinghe
• Infections in,– Skin– Subcutaneous tissue– Fasciae – Muscles
Erysipelas• Strep. Infections of dermis• Well demarcated, painful,
erythematous• indurated plaques, Blisters &
ulceration • Abrupt fever with chills• Face, legs • common in very young, old,
debilitated patients• lymphoedematous• erysipelas and Cellulitis overlap
often• Treatment: Penicillin IV/IM
Impetigo • A contagious superficial infection of the skin • Staphylococci or β-haemolytic streptococci• common in children • usually involves the skin of the face, often around the
mouth and nose. • spread by direct contact• Minor abrasions and other skin lesions predispose to
infections• Prevention is by good personal hygiene , particularly
hand washing with soap.
• It has two forms:1. Non-bullous
Streptococcus pyogenes "honey-crust" lesions
2. BullousStaphylococcus aureusrupture of the bullae
"varnish-like" crust
Treatment• Usually self-limiting• Avoid precipitating factor (e.g., exfoliation)• Localized– topical fusidic acid tds. (for MRSA)
• mild and localized – Topical antibiotic
e.g.; topical mupirocin
• Extensive disease–oral flucloxacillin, Erythromycin
• Other close contacts should be examined • children should avoid school for 1week after
starting therapy. • resistant to treatment or recurrent– take nasal swabs and check other family
members. • Eradication of nasal carriage–Nasal mupirocin
Folliculitis
• Infections of the superficial part of the hair follicle
• itchy or tender papules and pustules.
• Staphylococcus aureus
• Small pustules often pierced by a hair
• Legs, face – (sycosis barbae)
• commoner in humid climates and when occlusive clothes are worn.
• Extensive, itchy folliculitis in HIV infection.
Treatment
• topical antiseptics• topical sodium fusidate • mupirocin containing ointment• oral antibiotics –flucloxacillin or erythromycin
• If chronic – Detect and treat carrier state
Boils (furuncles)• Staph. Infections of the deeper part of hair follicle• most common on the face, neck, armpit, buttocks, and
thighs• On central face – danger of cavernous sinus thrombosis
• Tender, red, cone shaped swelling• heal with scarring• Recurrences may occur • Exclude carrier state• Treatment: Antibiotics• If large – need incision
CARBUNCLE
• Deep staph. Infection of several adjacent hair follicle
• cluster of boils that form a connected area of infection
• neck, back, thighs• In diabetics & debilitated• Treatment– Antibiotics,– Surgical incision
Ecthyma
• By both streptococci and staphylococci
• Ulcer forms under a crusted surface of the infection
• Heals with scarring
• Poor hygiene and malnutrition are predisposing factors
• Minor injuries and other skin conditions determine the site
• Treatment- – Improved hygiene and nutrition
– Antibiotics
(phenoxymethylpenicillin and flucloxacillin)
Cellulitis • Infection of normal skin flora or exogenous
bacteria (S. aureus and ß-haemolytic streptococci)
• Deep skin or subcutaneous layer• Hx of Trauma and Ulceration• Organisms enter through breach in skin• Infection can spread to blood stream Bacteremia /septicemia.• lower leg , hand ,nose ,periorbital
Clinical features • Acute localised pain• Oedema• lymphangitis
&lymphadenitis – Hot painful erythema
streaking, progressing proximally from the affected area, tracking along lymphatics
• +/- blister• Fever, Malaise,
Leucocytosis
Predisposing factors
DiabetesAlcoholismMalignancyDrug abusevenous stasislymphoedema
Investigations
• Swabs taken from relevant sites (from leading edge or aspirating blisters)
• Gram stain and Blood cultures• Serological-– antistreptolysin O titre (ASOT) – antiDNAse B titre (ADB)
Management• Elevate limb.• Treat underlying Cause• Antibiotics– Phenoxymethylpenicillin – erythromycin– flucloxacillin (all 500 mg
qds)– Vancomycin– Linezolid– Clindamycin
• Widespread– IV antibiotics (3–5 days) ,2
weeks (oral)
• Recurrent– low dose antibiotic
prophylaxis (phenoxymethylpenicillin)
MRSA Cellulitis
Complications-Local
• Blisters• Skin necrosis• Thrombophlebetics • Lymphadenitis• Abscesses
• Bacteremia• Septicemia • Osteomyelitis• Meningitis
Complications-Systemic
Skin abscess
• Subcutaneous• localized collection
of pus • surrounded by
granulation tissue• Hx of – penetrating injury– infection of haematoma
• S. aureus is the common infecting organism• Poor hygiene is predisposing• Rx- incision and drainage
Features:
Cellulitis present
Swollen
Soft center
feels like fluid underneath
Painful
TenderCellulitis
Abscess
Necrotizing fasciitis• Surgical emergency• Polymicrobial Infection of the fascia
Type 1- E.coli, Pseudomonas, Proteus, Bacteroides, Clostridium
Type 2- Streptococcus• May proceed rapidly to underlying muscle.
• Diagnosis is often delayed
• Primarily a clinical diagnosis
• Rapid progression to septic shock• Mortality 30-50%
Clinical Features
• Severe pain at the site of initial infection
• Tissue necrosis. • spreading erythema• pain • soft tissue crepitus– (infection tracks rapidly
along the tissue planes)
• Fever ,Tachycardia
Diagnose on signs and symptoms.
Imaging- air in the tissues.
Clinical findings in necrotising fasciitisEarly findings1. Pain2. Cellulitis3. Pyrexia4. Tachycardia5. Swelling6. Skin anesthesia
Late findings1. Severe pain2. Skin discoloration (purple or
black)3. Blistering4. Hemorrhagic bullae5. Crepitus6. Discharge of “dishwater” fluid7. Severe sepsis or systemic
inflammatory response syndrome8. Multi-organ failure
• Treat aggressively and promptly• antibiotics –Type 1- –Broad-spectrum combination (amoxicillin , imipenem, levofloxacin)
–Type 2 • benzylpenicillin and clindamycin
• urgent surgical exploration– Extensive debridement or– amputation (if necessary)
Necrotizing fasciitis after debridement
•
Staphylococcal scalded skin syndrome
• exfoliate or epidermolytic toxin.
• rapidly spreading tender erythema
• Dermonecrosis• Outer layer of the epidermis
peel off• Blistering• Ritter's Disease of the
Newborn - most severe form of SSSS
• Affects– infants, immunosuppressed , renal disease,
Malignancy• Mortality – higher in adult
• Diagnosis – Clinical– Culture– Frozen section examination of skin – shows split
• Treatment: IV antibiotics & nursing care or Self limiting.
Hidradenitis suppurativa
• Infection in Apocrine sweat glands• Common in Axillae and groin and in females• Multiple tender swellings • Enlarging and discharging pus• Recurrence • worse in obese individuals• Rx- – weight loss– oral retinoids (Vitamin A)– Zinc gluconate
Erythrasma• Chronic skin infection of
Corynebacterium
• Macular wrinkled, slightly scaly pink ,brown or macerated white areas
• armpits ,groin or between toe webs
• Coral pink under Wood’s light
• prevalent among diabetics, the obese, and in warm climates
• Rx – Topical fusidic acid ,Miconazole
Pyomyositis• S. aureus & Streptococcus
infection of the skeletal muscles
• pus-filled abscess• most common
in tropical areas- “ myositis tropicans”
• can affect any skeletal muscle• most often infects the large
muscle groups e.g.-quadriceps or gluteal
muscles
• Fever, Sepsis, Localized inflammation
• Muscle pain• Predisposing factors-
Immunodeficiency, IVDAs, Trauma and malnutrition
• Complications- Abscess, sepsis
• Rx- Drain surgically and antibiotics
Gangrene• Clinical situation where extensive tissue
necrosis is complicated by bacterial infectionDry gangreneWet gangreneGas gangrene
• Predisposing factors– Serious injuries – Ischemia due to atherosclerosis and PVD –Diabetes
Dry Gangrene
• The result of ischaemic coagulative necrosis.
• Black, dry, sharply demarcated
• Secondary bacterial infection is insignificant
E.g. Gangrene of extremities in thrombo-embolic occlusion of vessels
Wet Gangrene
• Tissue necrosis is complicated by severe infection.• Swollen, reddish-black foul smelling tissue.• Extensive liquefaction of dead tissue occurs due to
invasion of organisms & acute inflammation.• No clear demarcation between dead and viable
tissue.• Occurs in extremities and internal organsE.g. Diabetic gangrene of foot
Gangrene of bowel
Gas Gangrene (Clostridial myonecrosis)
• Clostridium perfringens
• Extensive tissue destruction
• gas production by fermentative action of bacteria.
• Swollen reddish-black foul smelling tissue with crepitus.
Treatment
• usually surgical debridement• amputation (if necessary) • Antibiotics alone are not effective
Thank you!