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EDUCATIONAL WORKSHOPS 2009
KEYNOTE PRESENTATIONKEYNOTE PRESENTATION
Management of the diabetic foot
Author: Paul Chadwick, Salford Royal Hospitals Trust
Sponsored through an unrestricted educational grant from Novartis Pharmaceutical Ltd to help support the
cost of developing and hosting this educational workshop series
Case HistoryA 76 year old man was admitted as an emergency with a
red and swollen right footApyrexial and haemodynamically stableDiagnosed with type 2 diabetes two years earlierOral hypoglycaemic therapy: blood sugar control
moderate
Author: Paul Chadwick, Salford Royal Hospitals Trust
InvestigationsX-ray of the foot showed changes consistent with both
osteomyelitis and soft tissue infectionC-reactive protein 219 mg/l (<10mg/l) Neutrophils 19.2 x109/l (4-11 x109/l)Plasma glucose 24.6 mmol/l (3-6 mmo/l).
Author: Paul Chadwick, Salford Royal Hospitals Trust
Illustration reproduced with permission from Clinical Publishing Ltd, Oxford
Diagnosis & Initial managementModerate diabetic foot infection
limb-threateningcritical ischaemia not present
Treated empirically with IV vancomycin and piperacillin/tazobactam
Author: Paul Chadwick, Salford Royal Hospitals Trust
Microbiological investigationPolymicrobial infection
Gram stain of showed neutrophils, Gram positive cocci and Gram positive bacilli
Enterocoocci and alpha-haemolytic Streptoccoci were isolated from pus
At least five different species comprising Gram positive cocci and Enterobacteria were cultured from superficial swabs.
Author: Paul Chadwick, Salford Royal Hospitals Trust
Surgical InterventionOn day 4 debridement was undertaken to remove
infected bone and soft tissue
Enterococcus faecalis, Propionobacterium sp. and Escherichia coli were isolated from deep pus and tissue samples.
Author: Paul Chadwick, Salford Royal Hospitals Trust
Further managementOn day 7 piperacillin-tazobactam was changed to oral
amoxicillin plus ciprofloxacin. 4 weeks of antimicrobial therapy were given in totalOngoing wound and foot care was provided by the
Podiatry team
Author: Paul Chadwick, Salford Royal Hospitals Trust
Diabetic foot infectionMost common reason for diabetes-related admission to
hospital
High morbidity – may result in amputations
Author: Paul Chadwick, Salford Royal Hospitals Trust
Why does DFI occur?Foot ulceration is the major factor and occurs secondary
to peripheral neuropathy and/or vascular insufficiency (neuro-ischaemic foot ulceration)
Hyperglycaemia and other metabolic disturbances contribute through immunological (e.g. neutrophil) dysfunction and poor wound healing
Author: Paul Chadwick, Salford Royal Hospitals Trust
Prevention of DFIAppropriate foot care/pressure relief
Podiatry services
Good glycaemic controlSpecialist diabetes services
Author: Paul Chadwick, Salford Royal Hospitals Trust
CID 2004; 39:885-910
Multidisciplinary Foot-care TeamPhysicianPodiatristMedical Microbiologist/ID PhysicianVascular surgeonFoot surgeonRadiologist
Author: Paul Chadwick, Salford Royal Hospitals Trust
Microbiological SamplesSamples should be collected following cleansing and
debridementTissue samples should be obtained from the base of an
ulcer by curettage, or at surgeryBone biopsy (including histopathological examination) is
important in establishing a diagnosis of osteomyelitisSamples should be transported without delay to the
laboratory and cultured under both aerobic and anaerobic conditions.
Author: Paul Chadwick, Salford Royal Hospitals Trust
Microbiological pathogensInfection is typically polymicrobial where ulceration is
presentAerobic Gram positive cocci
Staphylococcus aureusΒ-haemolytic streptococci
EnterococciEnterobacteriaceaeObligate anaerobes(Nonfermentative Gram negative rods)(Candida spp.)
Author: Paul Chadwick, Salford Royal Hospitals Trust
Diagnosis and AssessmentDFI is diagnosed clinically by signs and symptoms of
inflammationInfections are categorized as mild, moderate or severe,
on the basis of clinical and laboratory featuresCategorization helps to guide appropriate clinical
managementAssessment made as to whether an episode is life or limb
threatening
Author: Paul Chadwick, Salford Royal Hospitals Trust
Mild infectionPurulent or inflamed wound presentLimited to skin and superficial soft tissuesInflammation extends <2cm from woundNot systemically unwell
Treatment usually by oral routee.g. flucloxacillin, doxycycline, clindamycin
Microbiological sampling not routinely required for mildinfection unless recent antimicrobial therapy or previousantibiotic-resistant organisms
Author: Paul Chadwick, Salford Royal Hospitals Trust
Moderate infectionPurulent or inflamed wound present in a patient who issystemically well and/or one of the followinginflammation extends >2cm from woundlymphangitisspread beneath superficial fasciaabscess formationnecrosis or gangreneinvolvement of muscle, tendon, joint or boneTreatment by oral or parenteral routes according to clinicalassessment and choice of agent
Author: Paul Chadwick, Salford Royal Hospitals Trust
Moderate infectionTreatment options includeamoxicillin/clavulanateclindamycin + ciprofloxacinrifampicin + levofloxacinpiperacillin/tazobactamertapenemNB. Choices influenced by local policy with consideration oflocal issues such as C. difficile and MRSA incidence
Add glycopeptide, linezolid or daptomycin if MRSA infectionis suspected or infection is life/limb-threateningAuthor: Paul Chadwick, Salford Royal Hospitals Trust
Severe infectionInfection in a patient with evidence of systemicinflammatory response syndrome
IV treatment, at least initially, as an inpatient, e.g.clindamycin + ciprofloxacinpiperacillin/tazobactammeropenem or imipenem/cilastatin
Add glycopeptide, linezolid or daptomycin if MRSA infectionis suspected or infection is life/limb-threatening
Author: Paul Chadwick, Salford Royal Hospitals Trust
Diagnostic ImagingImaging should always be considered to identify soft
tissue abscesses or osteomyelitisOsteomyelitis is present in 30% DFIIt is important to identify underlying osteomyelitis as this
influences the choice, dose, route and duration of antimicrobial therapy, however
There is no single, non-invasive, highly sensitive and specific test for osteomyelitis
MRI can help to identify bone involvement (marrow oedema) and define its extent.
Author: Paul Chadwick, Salford Royal Hospitals Trust
Clinical signs of osteomyelitisThe following are associated with osteomyelitis
Inflamed, swollen (‘sausage’) toePresence of exposed bonePositive ‘probe-to-bone’ test
Author: Paul Chadwick, Salford Royal Hospitals Trust
‘Sausage toe’
Osteomyelitis of halluxProbe to bone?
X-rays and DFIPlain X-rays can be negative during the first 2-3 weeks of
osteomyelitisCharcot neuroarthropathy & gout may produce similar
appearancesPragmatic approach where osteomyelitis is suspected
but X-rays are negativetreat for osteomyelitis for two weeks then re-Xrayextend the course of therapy if new changes become
apparent.
Author: Paul Chadwick, Salford Royal Hospitals Trust
Osteomyelitis distal phalanx
MR imaging and DFIMarrow oedemaCortical discontinuityperiosteal reactiondebrissequestrasoft tissue oedema/indurationjoint involvementulcerationsinus formationabscess collection
Author: Paul Chadwick, Salford Royal Hospitals Trust
Osteomyelitis of calcaneum, T1 image
Image courtesy of Dr J Harris, Radiology Department, Salford Royal Hospital
Sinus
Marrow oedema
Marrow oedema
Soft tissue oedema
Osteomyelitis of 1st metatarsal head, STIR image
Image courtesy of Dr J Harris, Radiology Department, Salford Royal Hospital
Does the patient require surgery?Surgical intervention is often required. Urgent assessment
is needed by a surgeon with expertise in foot surgery where the infection is life- or limb-threatening. Vascular surgery may be needed where there is critical ischaemia.
? Excision & drainage? Debridement? Resection +/- reconstruction? Revascularisation? Amputation
Author: Paul Chadwick, Salford Royal Hospitals Trust
Wound Care IssuesOngoing debridement of non-viable tissue as requiredDressings to allow daily inspection of wound and to
encourage a moist wound-healing environmentRemove pressure from the wound (off-loading)
Author: Paul Chadwick, Salford Royal Hospitals Trust
Larval (Maggot) TherapyUseful for some sloughy woundsFeed by extra-corporeal digestion, secreting collagenasesEnzymes break down necrotic tissue into a semi-liquid
form that the maggots can ingest
Author: Paul Chadwick, Salford Royal Hospitals Trust
Contra-indications to larvaeMetronidazole Do not use in abdominal cavityDo not use in fistulaeNot recommended near major blood vesselsAnti-coagulant therapy in the community settingDry necrotic wounds (need to be softened)
Author: Paul Chadwick, Salford Royal Hospitals Trust
Sloughy wound beforeMaggot therapy
Maggot Therapy
Glucose ControlGood blood glucose control should be achieved
To manage the acute infection
To reduce the risk of future foot problems
Author: Paul Chadwick, Salford Royal Hospitals Trust
Duration of Antimicrobial TherapyContinued until the signs and symptoms of infection have
resolved (ulcer may persist)May be longer than for skin and soft tissue infections in non-
diabetic patientsMild soft tissue infections 1-2 weeksModerate-severe soft tissue 3-4 weeks
Osteomyelitis typically 6 weeks, unless all affected bone is completely removed by surgery (1-2 weeks)
Therapy ≥3 months sometimes required for extensive bone infection e.g. calcaneumNB. Courses may need to be longer than for non-diabetic patients with cellulitis
Author: Paul Chadwick, Salford Royal Hospitals Trust
Antibiotics in DFIAntimicrobial therapy can be challenging!Consider patient factors (e.g. age, renal function,
peripheral vascular disease)Side effects are common
Gastrointestinal intolerance of oral antibiotics, often to multiple agents
Hypersensitivity reactions (typically skin rashes) Deterioration in renal function may occur
Author: Paul Chadwick, Salford Royal Hospitals Trust
OHPAT and DFIOutpatient or home parenteral antimicrobial therapy maybe appropriate as prolonged IV therapy often needed forSevere infectionOsteomyelitisMRSA infectionIntolerance of oral agentsNo response to oral agents
Author: Paul Chadwick, Salford Royal Hospitals Trust