Neuropathy is a common complication of diabetes affecting up to 50% of people who have had diabetes more than 25 years. It classically presents as symmetrical loss of sensation in the feet but may also present with pain or unpleasant alteration of touch sensation (allodynia) in the feet. In addition to peripheral neuropathy, other manifestations include autonomic neuropathy and diabetic mono-neuropathies.

How long has the patient had diabetes?

Neuropathy typically develops after >10 years of diabetes. However, in a proportion of cases of T2DM it can even be a presenting symptom.

What is the anatomical distribution of the parasthesia?

The typical diabetic peripheral neuropathy causes a 'glove and stocking' distribution sensory loss.

The 'glove' part of the syndrome is not normally apparent until the 'stocking' part has progressed to around the level of the knees.

It is usually symmetrical and asymmetry should alert the clinician to a potential alternate diagnosis. Similarly, if the onset is not distal then the diagnosis is unlikely to be diabetic peripheral neuropathy.

Are there any symptoms in addition to parasthesia?

A proportion of patients with diabetic peripheral neuropathy will also experience neuropathic pain (painful diabetic neuropathy, PDN).

The pain is typically worse at night, exacerbated by contact with bed clothes and is often described as burning or lancinating.

Are there any symptoms of autonomic failure?

Patients who have had diabetic peripheral neuropathy for some time are at increased risk of autonomic neuropathy.

This may present with features of gastroparesis (early satiety, post prandial vomiting), small bowel bacterial over growth (intractable diarrhoea), cardiovascular autonomic failure (symptomatic postural hypotension) and sometimes other features such as gustatory sweating.

What other drugs is the patient taking?

A thorough drug history should be elicited to ensure there are no potential iatrogenic causes of neuropathy such as anti-tuberculous drugs, anti-convulsants and amiodarone.

Is there a history of excess alcohol intake?

Alcohol excess is a common cause of peripheral neuropathy.

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