Clinical guidelines for the management of adult diabetic foot infections

• Summary
• Background
• Clinical diagnosis
• Investigation
• Treatment
  • Non-antimicrobial treatment
  • Empirical antimocrobial treatment
• Appendix 1 Diabetic Foot Infection Pathway for A&E

Summary

Scope of the guideline

The guideline should be used Trust wide by medical, surgical, podiatrist and nursing staff for the management of patients presenting acutely with diabetic foot infections. The guideline may be used as guidance for primary care and community teams.

Criteria for use of guidelines

This guideline has been produced to promote consistent care of patients with diabetic foot infections. It outlines the actions necessary for managing these conditions and thereby reduces the risk to patients as much as possible. Whilst based on scientific evidence or professional consensus these guidelines are not intended to replace clinical judgement.

There are screening and referral pathways for diabetic feet, incorporating risk assessment for annual review on Leeds Health Pathways for primary care to access (nww.lhp.leedsth.nhs.uk/common/guidelines/detail.aspx?ID=319)

All patients with diabetic foot infection should be assessed by the specialist diabetic foot care team.

Please refer urgently via the Hot Foot Phone 07786250788 (Monday – Friday 08.00 – 15.00), out of hours refer to the medical SpR on call.

See main guideline below for:

Diagnosis
Investigations required
Non-Antimicrobial Management
Antimicrobial treatment

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Background

• Diabetic foot infections (infected foot ulcers, gangrene and osteomyelitis) are a major cause for admission for patients with diabetes mellitus.
• Diagnosing infection in the diabetic foot can be difficult and should be done in conjunction with a specialist team if in doubt.
• Infections may present with few of the classic signs of infection with deranged glycaemic control often being the only clue
• Conversely erythema in the diabetic foot may indicate other pathology such as trauma, inflammation/charcot arthropathy or ischaemia.
• If not treated appropriately, foot infections can lead to septicaemia, amputation and death.
• A multidisciplinary team approach (podiatrists, diabetologists, microbiologists, radiologists, vascular and orthopaedic surgeons, nursing staff and diabetes nurse specialists) is required to reduce morbidity and mortality for affected patients. (EL-A)

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Clinical Diagnosis

A “Hot Foot” in a patient with diabetes is a medical emergency and should be:

• assessed immediately by a clinician with the skills and resources available to manage such problems
• referred to and reviewed by a member of the Multidisciplinary Foot Care Team (MDFCT) with 24 hours

Foot Assessment

Remove all bandages and dressings on both feet to ensure a thorough assessment

• Is there evidence of infection?
  • Locally (in the foot):  Hot, red (erythema), indurated, swelling, pain (although the absence of pain in a neuropathic patient does not exclude infection)
  • Systemically: Shivers/Shakes, arthralgia/myalgia, headaches, poor appetite, lethargy, deranged Blood Sugars (when previously well controlled)

• Does the foot have normal perfusion?
  • Is it cool, pale and pulseless? Is there any necrosis (dead tissue)?

Severity of Infection Assessment(see Table 1- Severity Assessment for Diabetic Foot Infection)

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Investigation

Investigations are required to help determine the depth of the wound, the infecting microorganism and the general health/fitness of the patient (EL-A).

• Blood tests: FBC, U&E, plasma & capillary Glucose, CRP, Blood cultures. Add venous blood gases in patients who take insulin for their diabetes if capillary blood glucose > 14 mmol/L, to exclude Diabetic Ketoacidosis. Lactate should be requested (from laboratory or by Blood Gas) to assess sepsis if present
• Urine tests: Check for ketones in hyperglycaemic patients who take insulin for their diabetes.
• Microbiological tests:
  • Blood Cultures: should be collected if severe infection suspected.
  • Wound Swabs: are not ideal and should only be collected if no other sampling is possible. They grow a range of organisms, many of which may simply be colonising the wound rather than causing the infection
  • Tissue sample (bone or soft tissue): collected from the base of the ulcer following thorough debridement and cleaning to reduce contamination. This should be done by an operator skilled at debridement (usually a member of the MDFCT.
  • Tissue Sample Collection SOP
• Radiological:
  • Plain X ray: to look for evidence of gas in soft tissues / bony destruction / or fracture. Osteomyelitis cannot be excluded on the basis of plane radiography.
  • Magnetic resonance imaging (MRI): may be helpful to exclude osteomyelitis or abscess or determine if surgery is required
  • Magnetic resonance angiography (MRA): may be helpful to assess the vascular supply to the limb. This should only be requested following discussion with a Vascular Surgeon and MDFCT

Treatment

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Non-Antimicrobial Treatment

Having performed your clinical evaluation you may be able to assess the depth and severity of the infection. The assessment of diabetic foot infection can be difficult, the true depth of infection is not always apparent and the rate of spread can be alarming (EL-A). Frequent assessment by a suitably qualified health care provider is essential (frequency dictated by patient need and should be specified in the patients care plan).

All patients with diabetic foot infection should be assessed by the Multi-Disciplinary Foot Care Team urgently.

Please refer urgently via the Hot Foot Phone 07786 250788 (Monday – Friday 08.00 – 15.00), out of hours refer to the Leeds Teaching Hospitals Medical SpR on call.

• Superficial/Mild infections may often be treated with oral antibiotics on an out patient basis under the close supervision of the Multi-Disciplinary Foot Care Team (see guidance below). (EL-A)
• Most other infections will require:
  • Admission
  • Specialist assessment
  • Intravenous antibiotics (see antibiotic guidelines)
  • Rehydration
  • Pumped insulin therapy and regular capillary glucose monitoring
  • DVT prophylaxis
• An urgent Vascular Surgical opinion (on call registrar, via LGI switchboard) is recommended for Moderate/Severe infections requiring admission if the need for surgical debridement is suspected. (EL-D) This would include patients with a clinical suspicion of abscess formation, evidence of rapidly progressing or penetrating infection or any other case that causes concern after discussion with the on call Consultant Physician.
• Removal of infected tissue and abscess drainage may be urgently required so the patient must be fasted until the need for surgery is excluded.
• A less urgent vascular surgical opinion may also be indicated to assess the need for revascularisation once the acute infection is controlled.

General wound care, dressings and diabetic foot ulcers (EL-D)

• Patients should be non-weight bearing to aid healing of their ulcers
• Sterile, non-adhesive dressings should be used to cover ulcers to protect them from trauma, absorb exudates, reduce infection and promote healing
• Wound with low levels exudate - use Inadine® (unless iodine allergy) and a dry dressing
• Wound with high levels exudate - use Aquacel Ag® and a foam dressing
• For dressings advice please liaise with specialist diabetes podiatrist via Hot Foot Phone - 07786 250788

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Empirical Antimicrobial Treatment

Targeted Antimicrobial Therapy

• Empiric antimicrobial therapy should be reviewed in light of appropriate culture and sensitivity results.
• Other antimicrobials with special considerations which may be used for empiric and targeted therapy include:
  • Linezolid : can rarely cause optic neuritis, thrombocytopaenia (and other blood dyscrasias). Licence is limited to a max. treatment duration of 28 days. Visual acuity and FBC should be checked before starting treatment and FBC should be checked weekly. Linezolid should not be given to patients taking medication with MAOI activity due to the risk of serotonin syndrome.
  • Daptomycin : IV only but can be offered as a once-daily preparation through the CIVAS service. Can rarely cause myositis. Statins should be stopped temporarily while on treatment and patients should be monitored with baseline and weekly CK testing.

These agents should be used only after consultation with an Infection Specialist.

• Co-trimoxazole  (contains trimethoprim and suxamethoxazole): Can cause GI upset and more rarely blood dyscrasias especially in the elderly. Consider concurrent administration of folic acid on treatment and monitor patients with weekly FBC’s.

Discharge from hospital and out-patient follow-up

• All patients should have a clear diagnosis and management plan (including planned duration of therapy) prior to discharge
• No patient should be discharged with penetrating / deep infection (EL-D). Patients with superficial infection may be discharged after liaison with the Multi-Disciplinary Foot Care Team (Hot Foot Phone- 07786 250788)
• All foot lesions must be inspected on the day of discharge (EL-D)
• All patients on discharge should be referred to the Multi-Disciplinary Foot Care Team for out-patient follow-up, using appropriate referral forms (nww.lhp.leedsth.nhs.uk/referral_info/detail.aspx?ID=164)

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Appendix 1 Diabetic Foot Infection Pathway for A&E