AKT · Endocrine/Diabetes & glucose

Diabetic neuropathy

Microvascular/metabolic nerve damage from chronic hyperglycaemia

Overview

Nerve damage from chronic hyperglycaemia, most commonly a length-dependent symmetrical sensory polyneuropathy ('glove and stocking'). Drives foot ulceration (with peripheral vascular disease) and Charcot arthropathy. Also autonomic and mononeuropathies. Managed with glycaemic control, foot protection and neuropathic-pain agents.

Recognise

Symmetrical distal sensory loss ('glove and stocking'), numbness, tingling, burning pain, worse at night; loss of ankle reflexes and vibration sense
Insensate foot → painless ulceration (pressure points), and Charcot neuroarthropathy (warm, swollen, deformed foot)
Autonomic: postural hypotension, gastroparesis, erectile dysfunction, gustatory sweating; mononeuropathies (e.g. CN3 palsy — pupil-sparing)

Red flags

Foot ulcer with infection/ischaemia, or a warm swollen foot (Charcot) → urgent foot-protection/multidisciplinary team
New mononeuropathy/foot drop → exclude other causes

Differentials & how to tell them apart

B12 deficiency / alcohol neuropathyother causes of a symmetrical sensory neuropathy — check B12, history

Peripheral vascular diseaseclaudication, absent pulses, ischaemic (painful, punched-out) ulcers — often coexists

Lumbar radiculopathydermatomal, asymmetric, with back pain

Investigations

Annual foot check (10 g monofilament, vibration, pulses). Exclude other causes of neuropathy (B12, thyroid, alcohol, drugs). Clinical diagnosis.

Management

Glycaemic control + foot protection; amitriptyline/duloxetine/gabapentin/pregabalin for painful neuropathy

1Optimise glucose; structured foot care and annual risk stratification. For painful neuropathy, offer amitriptyline, duloxetine, gabapentin or pregabalin (one first-line agent; switch if not tolerated/ineffective).Gate: A warm, swollen, sometimes painless foot in a neuropathic diabetic is CHARCOT until proven otherwise → offload immediately and refer (not 'just cellulitis'); an ulcer with ischaemia/infection needs urgent MDT
2Refer to the foot-protection/multidisciplinary team for ulceration/Charcot; manage autonomic features (postural BP, gastroparesis, ED).

Glycaemic control + foot care — the foundation; podiatry, footwear, education to prevent ulceration

Neuropathic pain agent (amitriptyline, duloxetine, gabapentin or pregabalin) — first-line — choose one, switch if ineffective; capsaicin/tramadol as adjuncts

Key points

Insensate foot = ulcer risk; the painless warm swollen foot is Charcot, not infection. Treat painful neuropathy with one of the four agents, not an opioid.

Monitor & prognosis

Annual foot check; pain response.

Progressive; foot complications are limb-threatening.

Source: NICE NG19 (diabetic foot); NG28