wk11- diabetic foot infections Flashcards
what is neuropathy
caused by damage to peripheral nerves
types of diabetic neuropathy
- sensory neuropathy- burning, tingling or paraesthesia in a stocking and glove distribution or numbness
- motor neuropathy- atrophy in the intrinsic muscles of the foot, resulting in toe clawing and changes to the architecture of the mid foot leading to pressure redistribution over the metatarsal heads
- autonomic neuropathy results in increased skin atrophy, dry or overly moist skin, hair loss to legs and brittle toe nails
what happens with the blood vessels and nerves in the foot of a diabetic?
reduced blood flow and as a result a damaged nerve
the main bacteria on the foot is?
Staphylococcus species account for 70% of the normal skin microbiome on the plantar zone of the foot.
unregulated inflammation results in which of the following symptoms/conditions
tissue damage
pain
oedema
how do infectious agents persist in wounds 6
-change in gene expression (change in virulence factors)
-altered microbial growth (reduced metabolic rate/reproduction)
-resistance caused by impaired host immune defenses
-resistance caused by antimicrobial resistance
-resistance caused by resistance to disinfection
-impaired wound healing dur to biofilm formation
why do diabetics have delayed wound healing
sub-optimal blood flow to peripheral limbs, and impaired nutrient supply required to support the healing process.
the most common diabetic foot infections?
Staphylococci or streptococci- as the depth and severity of the infection increases, these infections become polymicrobial and include with Gram-negative and anaerobic infectious agents.
as resistance increases and species number also increases the infection goes from neuropathic to?
neuroischemic
traits of neuropathic infections
warm
well perfused
palpable pulses
sweating is diminished
skin dry and prone to fissuring
traits of neuriischemic infections
cool
poorly perfused
pulseless
skin thin, shiny and hairless
when should foot infection be suspected and treated?
when 2 of the following are present
local swelling or induration
erythema extending more than 0.5 cm in any direction from the wound
local tenderness or pain
local warmth
purulent discharge.
wound assessment involves 3
Careful inspection to identify signs of infection
Debridement to remove necrotic tissue
Probing to assess wound depth
medical imaging is useful when the wound extends beyond what layer?
superficial fascia
when shouldn’t microbial investigations and antimicrobial therapy be used
when theres no clinical signs and symptoms of infection
swabbing wounds how to
Swabbing dry crusted areas is unlikely to yield the causative pathogen
Remove debris (debride) and surface exudate and clean with sterile saline prior to specimen collection
Pass the sterile collection swab deep into lesion and firmly sample the leading (advancing) edge of the wound
why should uninfected wounds/ulcers not be processed in the diagnostic microbiology laboratory
all wounds are contaminated with infectious agents and ulcers are not meant to be sterile
interventions for wound management 5
-wound management (dressing, removal of biofilm and debridement)
-glycaemic monitoring and control
-pressure area care
-management of ischemia via vascularization
-treatment of infected wounds (antimicrobial therapy and antisepsis)
antimicrobial therapy for mild diabetic foot infections
-what level of infection, infectious agents, treatment duration and route
Involves only the skin and subcutaneous tissue
Erythema extends no more than 2 cm from the wound margin and there are no systemic features of infection
Gram-positive cocci (staphylococci, streptococci) with or without MRSA
1-2 weeks
orally
antimicrobial therapy for moderate diabetic foot infections
-what level of infection, infectious agents, treatment duration and route
Involves structures deeper than the skin or subcutaneous tissues (eg muscle, bone, joint, tendon)
Erythema that extends more than 2 cm from the wound margin.
Gram-positive cocci; gram-negative rods; anaerobes with or without multidrug-resistant organisms (e.g., MRSA, extended-spectrum beta-lactamase–producing strains (ESBLs), vancomycin-resistant enterococcus (VRE))
2-4 weeks
orally or parenterally followed by orally
antimicrobial therapy for severe diabetic foot infections
-what level of infection, infectious agents, treatment duration and route
Infection associated with systemic inflammatory response syndrome (SIRS)
Two or more of:
-abnormal temperature [more than 38°C or less than 36°C]
-heart rate more than 90 beats/minute
-respiratory rate more than 20 breaths/minute
-white cell count more than 12 × 109/L or less than 4 × 109/L, or more than 10% immature [band] forms
Gram-positive cocci; gram-negative rods; anaerobes with or without multidrug-resistant organisms (e.g., MRSA, ESBLs, VRE)
minimum 6 weeks
administer parentally then switch to orally
do adults or children have better blood supply?
children
