Management of diabetic foot complications
Clinical features and diagnosis
Clinical examination and risk classification of the diabetic foot
This chapter outlines techniques for the examination of the diabetic foot, including a look at available classification systems.
| Summary |
- Among patients with diabetes, foot ulceration is a common precursor to lower extremity amputation, providing an avenue for infection, and potentially causing progressive tissue necrosis and poor wound healing. Such ulceration is often associated with peripheral neuropathy and repetitive trauma.
- For the successful prevention of foot complications, it is important to identify high-risk patients. Screening essentially involves four elements:
- History of lower extremity disease
- Sensory neuropathy
- Peripheral arterial disease
- Limited joint mobility or structural foot and ankle deformity.
- Techniques and tools for the assessment of sensation, to screen for sensory neuropathy, include use of a tuning fork, the Semmes-Weinstein Monofilament, and vibration perception threshold testing.
- The high-risk patient can also be identified by clinical assessment, using scoring systems such as the Modified Disability Score, which uses standard clinical tools to produce a disability score that has been proven to be predictive of diabetic foot complications.
- When caring for diabetic foot ulceration, a clear classification system is necessary to ensure appropriate therapy, communicate risk and potentially predict outcome.
- There are seven important questions to be asked when assessing a diabetic foot wound:
- Where is the ulcer located?
- How large is the ulcer?
- What does the base look like?
- What do the margins look like?
- How deep is the ulceration? Are there underlying structures involved?
- Is there infection?
- Is there ischemia?
- There have been several diabetic classification systems reported in the literature. These include the Wagner Ulcer Classification and the University of Texas Ulcer Classification.
- The most common components of neuropathic ulceration risk can be identified using simple and readily available equipment in the primary care setting.
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Lavery LA, Armstrong DG. In: The diabetic foot: Medical and surgical management. Edited by Veves A, Giurini JM, LoGerfo FW. Humana Press, 2012. doi: 10.1007/978-1-61779-791-0_4
Classification of diabetic foot disease
This paper discusses the various systems used for the classification of Charcot arthropathy and for the classification of ulceration.
Summary
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- Classification systems for diabetic Charcot arthropathy can be divided into temporal and descriptive (anatomic) types. The temporal classification system of Eichenholtz, while imperfect, is widely accepted, and has allowed for meaningful discussion on treatment options based on disease state.
- The anatomic classification system of Cofield describes three patterns based on radiographic changes:
- Metatarsophalangeal or phalangeal involvement
- Tarsometatarsal joint destruction
- Destruction through the head or neck of the talus, navicular and cuneiforms.
- The anatomic classification system of Sammarco and Conti is based on patterns of bony destruction. Five anatomic patterns of Charcot midfoot involvement are described.
- The anatomic classification of Brodsky classifies Charcot arthropathy according to the area of the foot with maximum bony destruction radiographically. It is the most widely quoted anatomic classification system for Charcot arthropathy.
- The anatomic classification system of Schon established four types of midfoot arthropathy, and involves a clinical deformity severity stage based on the degree of collapse of the longitudinal arch of the foot; it was later modified to include a radiography severity scale.
- The authors conclude that the anatomic classification systems of Schon et al. and Brodsky et al. appear to be most useful for guiding and discussing treatment. They propose the Eichenholtz temporal classification system should be used for staging, while either the Schon et al. or the Brodsky et al. anatomic classifications should be applied to describe the location of disease.
- The most widely referenced classification system for diabetic foot ulcers, which is simple and easy to apply, is the Wagner and Meggitt classification – which uses six grades. Other classification systems of diabetic foot lesions include the depth-ischemia classification, the University of Texas classification, and the International Working Group on the Diabetic Foot classification.
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Taylor R. In: The surgical management of the diabetic foot and ankle. Edited by Herscovici, Jr D. Springer International Publishing, 2016. doi: 10.1007/978-3-319-27623-6_4
Diabetic polyneuropathy
This chapter outlines the neuropathic syndromes that occur in diabetes mellitus, with a focus on diabetic peripheral neuropathy and autonomic neuropathy.
Summary
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- Diabetic neuropathy encompasses several neuropathy syndromes, the most common presentation of which is chronic distal symmetrical polyneuropathy, known frequently as diabetic peripheral neuropathy.
- Diabetic peripheral neuropathy mainly presents as sensory loss, and is usually easily detected by simple clinical examination, with further assessment often necessary to determine severity.
- Acute painful neuropathies are transient, and characterized by acute onset of pain in the lower limbs. There are two distinct types:
- Acute painful neuropathy of poor glycemic control
- Acute painful neuropathy of rapid glycemic control or insulin neuritis.
- Other neuropathies include small fiber neuropathy, focal and multifocal neuropathies, proximal motor neuropathy, cranial mono-neuropathies, and thoraco-abdominal neuropathy.
- There are several pressure palsies that also fall under the umbrella of diabetic polyneuropathy, such as carpal tunnel syndrome, and ulnar nerve and other isolated entrapments.
- The pathogenesis of diabetic polyneuropathy remains unclear, but it is widely accepted that micro-vessel disease is important in this pathogenesis, and severe neural microvascular disease has been demonstrated in subjects with clinical diabetic neuropathy.
- Autonomic neuropathy has a gradual onset and is slowly progressive. Intensive glycemic control is critical in preventing onset and slowing progression of diabetic autonomic neuropathy.
- Diabetic peripheral neuropathy is painful in approximately half of all cases. The exact mechanisms of this pain remain to be fully elucidated, and its management poses a considerable clinical challenge. The most commonly prescribed first-line agents are pregabalin, duloxetine, gabapentin and amitriptyline. If pain is inadequately controlled opioids such as tramadol and oxycodone may be added.
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Tesfaye S. In: The diabetic foot: Medical and surgical management. Edited by Veves A, Giurini JM, LoGerfo FW. Humana Press, 2012. doi: 10.1007/978-1-61779-791-0_3
Clinical features and diagnosis of peripheral arterial disease
This chapter discusses features of peripheral arterial disease in patients with diabetes, with a focus on patient evaluation and diagnostic techniques.
Summary
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- Peripheral arterial disease is characterized by two distinct pathological processes:
- Nonocclusive microcirculatory impairment
- Macroangiopathy manifesting as atherosclerotic lesions.
- One of the most important steps to ensure salvage of the diabetic limb is assessment of the arterial circulation. This should start with taking a patient history and performing a physical exam, followed by the selective use of the vascular diagnostic laboratory.
- Arterial insufficiency should be considered in any patient who presents with foot ulceration or gangrene, even if it has already been determined to be neuropathic, or due to an infected ulcer.
- Pulse examination, including the status of the foot pulses, is the most important component of the physical exam, with ischemia always assumed to be present in the absence of a palpable pulse.
- Non-invasive arterial testing for the diagnosis of peripheral arterial disease includes the following, all of which have significant limitations:
- Doppler segmental pressures
- Toe pressures
- Doppler waveform analysis
- Pulsed volume recordings
- Duplex ultrasound
- Transcutaneous oxygen tension and laser Doppler perfusion.
- A thorough bedside evaluation with selective use of non-invasive vascular testing is usually sufficient for detecting arterial insufficiency in patients presenting with diabetic foot ulceration. If present, revascularization is indicated to save the limb. Only after determining that insufficiency is present is arteriography appropriate; it should not be considered a diagnostic tool.
- Peripheral arterial disease is common in diabetes. Missing a diagnosis of arterial insufficiency can lead to ongoing wound problems and even limb loss. Awareness of the features and a high level of diagnostic skill help lead to improved outcome and limb salvage.
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Akbari CM. In: The diabetic foot: Medical and surgical management. Edited by Veves A, Giurini JM, LoGerfo FW. Humana Press, 2012. doi: 10.1007/978-1-61779-791-0_5
The diabetic foot
This chapter reviews the various imaging techniques used in diabetic infectious arthropathies, highlighting ways for distinguishing these from neuropathic arthropathies.
Summary
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- An important difficulty faced by those involved in the management of diabetic patients is the identification of infections, and distinguishing these from neuropathic arthropathy.
- There are several patterns of neuropathic arthropathy (Charcot joint) that can occur, including atrophic, hypertrophic and mixed. To aid in the interpretation of radiographic findings, progression of neuropathic arthropathy has been classified into three stages, plus a preradiographic stage, by Eichenholtz. While not commonly used clinically, this staging helps provide an understanding of progression of a Charcot joint.
- In addition to radiography, other imaging techniques used in the investigation of neuropathic arthropathy include magnetic resonance imaging (MRI), computed tomography (CT), ultrasound and nuclear medicine.
- Diabetic foot infections most commonly occur due to skin barrier breakdown. Imaging can be useful for assessing diabetic foot complications, identifying osteomyelitis or septic arthritis and differentiation from an isolated neuropathic joint. MRI plays a particularly important role here.
- Again, several imaging modalities are useful in the investigation of diabetic foot infections, including radiography, used predominantly to reveal major structure abnormalities of the bones of the foot, MRI, ultrasound, CT, nuclear medicine and positron emission tomography.
- MRI is the most appropriate means of identifying osteomyelitis in diabetic foot infections, and differentiating it from the reactive bone marrow edema that is seen in the neuropathic joint.
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Legault KJ, O’Neill J. In: Essential imaging in rheumatology. Edited by O’Neill J. Springer-Verlag New York, 2015. doi: 10.1007/978-1-4939-1673-3_14