The Diabetic Foot

Authors: Ferdinand Ohanusi, Charlotte Davies / Editor: Swagat Mishra / Codes: CC10, HAP34, DC5, SLO1 / Published: 07/06/2022

We’ve all seen diabetic foot presentations in the Emergency Department (ED), but many more of them are managed successfully in primary care and podiatry clinics. As in many other areas, the ED has a huge role to play in prevention as well as treatment.

Pathogenesis

Without going into too many details, the combination of peripheral vascular disease and peripheral neuropathy can lead to problems with the feet of diabetics. The reduced sensation means that small wounds are not noticed and treated, so wounds deteriorate. The peripheral vascular disease leads to poor wound healing, with breakdown of the skin and soft tissue forming ulcers. For more details, look at the Calgary Guide. There may be associated arterial insufficiency contributing to the ulcers.

Neuropathy is evidenced by reduced sensation, especially to vibration. There may be associated deformity like pes cavus, claw toes, and a “rocker-bottom” sole. The sensory loss may be patchy and non dermatomal, so examination of the whole foot is recommended. This neuropathy is often symmetrical and may also be painful – follow the analgesic ladder.

Peripheral Vascular Disease (PVD)  is evidenced by poorly palpable pulses that may or may not be present with a Doppler.

Prevention

ED does have a role in public health, and it’s in everyone’s interest, especially the patients, for us to encourage foot care as much as possible. So we need to:

General practice examine their diabetic patients a lot more rigorously, and should have documented sensation and pulses recorded within the last twelve months as part of a QOF indicator, as described by Geeky Medics.

Management

When prevention hasn’t worked and patient has presented with a foot ulcer, not all of them need managing with antibiotics, amputations and admission. To start with, take a good history:

  • How long the ulcer has been a problem
  • Treatment so far, including antibiotics
  • Wound swabs and MCS results if known
  • Presence of pain
  • Systemic features
  • Smoking status
  • Glycaemic control
  • Compliance with treatment

Then examine your patient carefully. If they have dressings on, you have to get them off – to not look at the legs, if the ulcer is the presenting complaint, would be very poor care. Removal of dressings might be uncomfortable – consider soaking bandages off by putting the patient’s leg in a sharps bucket full of warm water – ask the patient what will work for them.

Examine the legs fully, describing the wound, and the vascular findings. You might need to use a hand held doppler to find the pulses. Diabetic foot ulcers are normally punched out lesions on the lateral aspect of the sole of the foot. If you take a photo to add into the notes, a description as well will be useful.

 

Investigations

*             Vital signs
*             Blood tests – FBC, U&E, CRP, LFT, Glucose as indicators of infective status.
*             Blood cultures in the systemically unwell patients.
*             Deep wound swabs in the systemically unwell patient – they are unlikely to be useful in the well patient as it is hard to work out whether the identified species are colonisation or not. Culture of debrided tissue is a lot more sensitive – but this should be taken by a specialist practitioner.
*             X-rays should be taken to determine any late signs of osteomyelitis.
*             Photography can be useful to prevent regular wound examinations – but remember these should be taken using official cameras, and not on your mobile phone.

Treatment       

  • Cleanse wound with sterile saline
  • Apply non adhesive dressing like adaptic (once it is unlikely anyone else is going to want to look at the wound – normally this is done once the post take Medical Consultant has reviewed the patient).
  • Issue crutches to enable offloading of ulcerated foot.
  • Refer to in or outpatient podiatry for review.
  • Provide psychological support – patients need to be supported to prevent deterioration of their ulcer. The effect on their lives of regular wound care, potentially offensively smelly wounds, and potentially amputation must be considered and not minimised.
  • Treat infection as per PEDIS and trust guidelines.

The clinical examination should guide management and treatment more than wound swab results. All wounds are colonised with bacteria, this doesn’t indicate an acute infection. The antibiotics you give will depend on your local guidelines but before you speak to your microbiology team, make sure you know the patient’s allergies and previous culture results.

Antibiotics are given until the infection has resolved, not until the wound itself has completely healed. Mild infection normally needs 1-2 weeks of treatment, with severe infection requiring 2-4 weeks of treatment.

PEDIS 1:                No antibiotics recommended

PEDIS 2:                Treat for likely Staph aureus or Streptococci, but can be polymicrobial, consider MRSA eg. Flucloxacillin

PEDIS 3:                Treat for likely Staph aureus or Streptococci, but can be polymicrobial, consider MRSA eg. Flucloxacillin and Metronidazole

PEDIS 4:                Treat for deep seated infection eg. Piperacillin-tazobactam
                             Consider MRSA eg. Add in vancomycin
                              Involve vascular surgery

Who treats these patients will depend on your hospital set up, and many will have multi-disciplinary foot teams. In most hospitals, the medical teams with the diabetologists lead on the care, with support from the podiatrists. Vascular involvement is normally only needed in PEDIS grade 4 infections, and where there is associated critical limb ischaemia – but do check your local hospital guidelines.

Gangrene

Gangrene should be treated as per PEDIS 3 or 4. Black toes are a sign of dry gangrene and vascular compromise, and if present in isolation don’t need treating acutely.

There’s also a nice summary of diabetic foot management in primary care from the BMJ infographic team available here.

Hopefully this blog post has reminded you of some of the important factors to consider when treating a diabetic foot ulcer in the ED. If you have any other tips or tricks, get in touch with us!

2 Comments

  1. Dr. Katherine Hartington says:

    interesting, thank you

  2. Olubusola says:

    Informative

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