/ Download pdf version of this discussion
Diabetic peripheral neuropathy develops in up to half of all people with diabetes and is one of the
main risk factors contributing to foot ulceration and eventual amputation. There are several types of neuropathies but
90% of people with diabetic peripheral neuropathy have symmetric distal polyneuropathy, often occurring in combination
with autonomic neuropathy.
The risk of developing diabetic neuropathy is proportional to both the magnitude and duration of hyperglycaemia therefore
it is less likely in people with optimal long-term control of HbA1c levels (< 55 mmol/mol). Other risk factors include
smoking, hypertension, obesity and dyslipidaemia, increasing age and a family history of neuropathy.
Diagnosis is based on clinical suspicion, generated by a combination of findings from the history and
examination. Other diagnostic possibilities that should be considered include medicines, systemic conditions, infections,
autoimmune disorders, toxins, trauma and inherited conditions.
Patients with symmetric distal polyneuropathy usually have a predominance of sensory symptoms over
motor symptoms with a mild, insidious onset and nocturnal exacerbations. Symptoms can vary widely and include the loss
of sensation to pain, temperature, touch, vibration and proprioception. Symmetrical symptoms usually first appear in the
toes and gradually progress proximally in a “stocking distribution” to involve the feet and legs. Involvement of the fingers
and hands may occur, however, usually in people with later-stage diabetic neuropathy. Motor symptoms such as atrophy,
weakness and unsteadiness are also more common later in the disease course.
Autonomic neuropathic dysfunction, with or without sensorimotor neuropathy, can involve the cardiovascular,
gastrointestinal, genitourinary, sudomotor (control of the sweat glands) and ocular systems.
Examination for peripheral neuropathy should include:
- A general inspection of the feet and the patient’s footwear
- Musculoskeletal assessment for deformity (including Charcot arthropathy)
- Neurological assessment, e.g. monofilament testing, tuning fork tests
- Vascular assessment of the feet, and assessment of the heart rate and blood pressure (lying/sitting and standing)
Management – The primary goal of treatment of diabetic neuropathy is resolution of the patient’s symptoms
and prevention of further nerve damage as there is no specific treatment that can reverse damage to the nervous system
damage. Good glycaemic control, however, may stabilise or even improve peripheral neuropathy over the long-term. Additional
management is aimed at controlling symptoms, particularly pain, and improving the patient’s quality of life. Protecting
insensate feet from trauma is also important to avoid the development of ulcers.
Mild neuropathic pain may respond to paracetamol or NSAIDs. If required, a tricyclic antidepressant or an anticonvulsant
can be considered. Consider adding a weak opioid, such as codeine or tramadol (short-term use only), if the pain is not
controlled. Topical treatment with capsaicin cream, 0.075%, can be considered for people with relatively localised neuropathic
pain who do not wish to take, or cannot tolerate, oral treatments. Non-pharmacological methods, e.g. exercise, should
also be encouraged.
When to refer patients – patients with atypical features or who fail to respond to management strategies
should be referred to a Neurologist for further investigation, including patients with:
- Pronounced asymmetry of the neurologic deficits
- Predominant motor deficits, mononeuropathy or cranial nerve involvement
- Rapid development or progression of the neuropathic impairments
- Progression of the neuropathy despite optimal glycaemic control
- Symptoms arising from the upper limbs
- Family history of non-diabetic neuropathy
- Pain that is difficult to manage, limiting the patient’s lifestyle and daily activities or if their underlying health
has deteriorated as a result
Peer group discussion points
- Do you routinely ask patients with diabetes whether they have symptoms of peripheral neuropathy, e.g. numbness,
tingling or pain?
- Up to 50% of people with type 2 diabetes are likely to develop peripheral neuropathy. If a patient could not detect
pressure from a monofilament during a routine foot check would you routinely go on to do further neurological
assessment, e.g. tuning fork tests for vibration sense or check for deep tendon reflexes?
- Topical treatment with capsaicin cream may be effective for patients with localised neuropathic pain, however,
there is debate regarding its effectiveness. If you have prescribed it for patients, have they reported benefit
from its use?
- Good glycaemic control is beneficial for patients with peripheral neuropathy; what strategies do you use to help
patients achieve better glycaemic control?