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Diabetic foot infection
Dr Aurélien DINH, MD
Pr Louis BERNARD, MD, PhD
Infectious Diseases, University Hospital Tours, France
Corresponding author: [email protected]
Meeting of the Lebanese Society of Rheumatology
6th of November 2009, Beyruth
Definition
• Infection is due– to tissue infestation – by micro organisms – with inflammatory response
• Diabetic foot infection (DFI) is due to foot ulceration
• Colonization should be distinguish from infection
• Colonization is continuous on wound
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No infection !
Infection !
Diagnosis
• Diagnosis of infection is clinical (not bacteriological):– Induration– Warmth– Erythema– Local tenderness– Purulence discharge
• DFI involve soft tissue with or wthout bone tissue (osteitis)
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© Copyright SPILF
Are all diabetics equal for foot infection ?
• NO !!• Diabetic foot infection is mostly
due to peripheral neuropathy• Mainly because of
– deformation (neuroarhropathy) – insensitiveness
Deformation
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© Copyright SPILF
Sensitive neuropathy
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Peripheral neuropathy• Lack of protective sensation• Cracking skin>>Neuropathy is favourable to
wound• Neuropathy delays diagnosis and
treatment of wound• Neuropathy does’nt help to take
care (no pain, no care)
Physiopathology of DFI
• Foot wound and infection are more frequent in diabetic population
• Risks factors are subject to debate but :– Deficit of cellular mechanism of defense (hyperglycemia)– Peripheral neuropathy– Hyperpressure– No off-loading– Chronicity of wound– Hypoxy– Vascular disease– Anatomic deformation
Predictive factors of outcome
• Peripheral vascular disease– restrict debridment– Reduce antibiotic efficacy – Encourage gangrene
• No off-loading– Encourage by insensitivity to pain– Refrain from wound healing – Encourage infection and osteitis
Clinical classification (staging in DFI)
• UT (University of Texas) Classification– Easy to use, based on : depth of wound/
infection/ vascular disease
• IWGDF-IDSA classification (International working group on the diabetic foot classification) focus on infection stage
• Others classifications : Wagner, Lipsky, PEDIS
UT Classification
Wound prevalence by grade and stage
Prevalence of amputation within each wound category
IDSA-IWGDF classification
Lavery, CID 2007
How to collect specimens for microbiological
diagnosis ?• Bacteriological samples :
– should be performed • Only in case of clinical infection • Before antibiotic therapy
– Several methods exists
How to get reliable microbiological data ?
• How to get bacteriological specimens ?• There is no consensus to distinguish the best
method• Local protocols should be done by clinicians
and microbiologists• They should specify: objective of analysis,
method of taking specimens, transport, culture…
• The goal is to identify micro organisms involve in bacterial invasion and to avoid colonization
General principles
• Wound should be cleanse and debride before obtaining specimens for culture
• Samples should – be clearly identified – and promtly send to laboratory
Microbiological evaluation
• Generally : blood cultures or cultures of deep tissue biopsy specimen>>more clinically significant
• Superficial swab: easy to perform, not invasive
• Scraping with a curette• Needle Aspiration• Soft tissue biopsy• Bone biopsy (osteomyelitis)
Superficial swab
Needle aspiration
Soft tissue biopsy
Bone biopsy
62
65
68???
Sapico 1984, Lavery 1995, Slater 2004, Kessler 2006, Senneville 2006
30
69
24
Microbiological correlation between superficial sample and deep tissue
biopsy (from E. Senneville)
Microbiological correlation (between kind of wound and germs involved)
Lipsky CID 2004
Bone biopsy
• Gold-standard test for diagnosis osteo myelitis (histological analysis should be performed)
• Usefulness reliably recovering the pathogens responsible for bone infection
• It should be performed passing through a clean zone
Concordance between superficial swabs and bone biopsy
Senneville CID 2006
Recommanded wash out period before bone biopsy :
+15 days
0
1
2
3
4
5
6
7
1 5 9 13 17 21
pénicilline
céfalotine
netilmycine
clindamycine
ciprofloxacine
rifampicine
Witso et al. Acta Orthop Scand, 1999
Bone biopsy
Which relevance for other laboratory investigations ?
• Limited interest • No biological markers can help to
make difference between infection and colonization
• Kinetic of the value of C Reactive protein could be interesting to estimate response to treatment
Assess risk factors
• Mechanical factors• Vascular factors
– Clinical data– Systolic index pressure– Doppler – Transcutaneous oxygen pressure– others
© Copyright Pr Louis BERNARD
DFI management
• Multidiscplinary team• Management
– Strict glycemic control – Strict off-loading– Medical debridment– Wound care plan– Edema controll– Tetanos vacinal status
Glycemia/off loading
• Glycemia – should be strictly controlled:
• close monitoring, • insulinotherapy
• Off loading : – The major factor !!– It should be total and continuous
Atherosclerosis/Debridment
• Seek for vascular disease to correct
• Mechanical debridment to clean tissue– Physically excise dead and unhealthy
tissues– Reduces bacterial burden– Removes reservoir of potential pathogens
>> help to heal
Local therapy
• Local antiseptic : – No Proof of effectiveness !!
• Local antibiotherapy : – No Proof of effectiveness !!
Wound care
• Wound dressing – should be performed daily, – no adhesive or occlusive devices
• But there is:
– No good trials– No consensus– No study cost/effectiveness
Others
• Tetanos vaccine status : YES
• Hyperbaric oxygenia : no proof of effectiveness
• Growth factors: no proof of effectiveness
Antibiotherapy
• Indication: when there is infection and after microbiological sample performed
• Empirical antibiotic regimen: – Effective against staphylococcus aureus– Decrease with bacteriological results– Depending on severity of infection– Depending of diagnosis of osteitis– Mostly parenteral at the beginning– With good biodisponibility and penetration
Complex choice of antibiotherapy
• Bacterial spectra >> effective on Staphylococcus• Biodisponibility >> intra veinous ?• Penetration >> high dose ?• Tolerance >> visceral failure• Interaction• Bitherapy >> to prevent resistance• High dose >> because of atherosclerosis
Treatment duration
Lipsky, CID 2004
Surgical strategies
• Vascular surgeryVascular surgery– by pass
– Percutaneous transluminal angioplasty
• Orthopedic surgery– To control infection
– To attempt to salvage limb
Vascular surgery (1)
• Vascular disease exacerbate infection>> revascularization
• Revascularisation can be realise – to save the limb – or to help healing
Vascular surgery (2)
• In case of critical ischemia– revascularization should be perform when
sepsis is controlled– In case of emergency: revascularization
should be performed close or at the same time
• When ischemia is less critical: revascularization should always be discussed
Before
After
Benefit of revascularization (1)
Jacqueminet Diabetes care 2005
Jacqueminet Diabetes care 2005
Benefit of revascularization (2)
Methods for local treatment
• Most important !!• Excision of infected tissues• Limited debridment of necrotic tissues• Drainage of deep abscess and deep space
infection• In some cases : amputation = the only option• Surgery should attempt to preserve the
integrity of walking surface
Indications for surgery
• Urgent surgical consultation:– Fasciitis and necrosis– Gangrene/abscess
• Delay surgery : – cellulitis not responding after 3 days of efficient
antibiotic therapy
• Indications for amputation:– If vascular disease: state on vascularization
possible procedure– If non vascular disease: if extensive soft tissue lost
or fasciitis with life or limb-threatening infection
Osteitis in DFI
• When think about it ?• Which imagery ?• Surgery management• Which antibiotic therapy ?
Physical examination
• No healing despite appropriate care
• Positive probe to bone test – (PPV:50-89% ; NPV>95%)
• Sausage deformity
Accuracy of probe to bone test
Lavery Diabete care 2007
Ulcers not healing
CRP and osteitis
Enderle et al. Diabetes Care 1999
Radiological diagnosis of osteitis (1)
Dinh MT CID 2008
Kapoor et al. Arch Int Med 2007
Radiological diagnosis of osteitis (2)
Radiological diagnosis of osteitis (3)
Termaat JBJS 2008
Surgery for osteitis
• Conservative surgery– Limited resection– No osteo synthesis– Antibiotherapy from 4 to 6 weeks
(parenteral then oral)
• Different from acute Charcot foot
Hartemann-heurtier,
Senneville,
Diabetes metabolism 2008
Microbiology in osteitis of DFI
Hartemann-heurtier, Senneville, Diabetes metabolism 2008
Antibiotic treatment for osteitis in DFI
Hartemann-heurtier, Senneville, Diabetes metabolism 2008
Preventive actions
• Education: – risks of neuropathy and vascular
disease, self management and examination
• Pedicure: – nails care, managing hyperkeratosis
• Shoes: – should fit, trauma due to shoes are
the first cause of diabetic ulcers• Preventive surgery:
– if major deformation to avoid futur hyperpressure
Take home messages
• Diabetic foot ulcers are– Coming on insensitive
foot– Always colonized– Infection diagnosis is
clinical– Outcome depending
mostly on atherosclerosis and tipping off
• Management need – Precise wound care– Assess risks factors– Microbiological
specimens– Antibiotherapy– Surgery some times
Thank you for your attention !
• Thanks to – french infectious disease society, – french society of vascular surgery, – french society of microbiology
• Pr Agnès Hartmann-Heurtier (Endocrinology, Pitié Salpétrière)
• Dr Eric Senneville (Infectious disease, Lille)
