Diabetic neuropathy is a common microvascular complication of diabetes, caused by chronic hyperglycaemia, oxidative stress, and metabolic dysfunction. It affects up to 50% of people with long-standing diabetes and is a diagnosis of exclusion. 👉 Always rule out reversible causes (B12 deficiency, alcohol, thyroid disease, uraemia, medications) before attributing symptoms to diabetes.

🔬 Pathophysiology

Chronic hyperglycaemia → polyol (sorbitol) pathway activation, oxidative stress, advanced glycation end-products → neuronal injury.
Microvascular damage to vasa nervorum → axonal degeneration and demyelination.
Affects both small fibres (pain, temperature, autonomic) and large fibres (vibration, proprioception, reflexes).
Autonomic involvement may affect cardiovascular, gastrointestinal, genitourinary, and sudomotor systems.

🛡️ Prevention (NICE 2024)

🎯 T1DM: Early, intensive glycaemic control reduces risk of DSPN & autonomic neuropathy.
🎯 T2DM: Optimise HbA1c; intensive control reduces progression but may not fully prevent neuropathy.
⚖️ Lifestyle: weight optimisation, regular exercise, metabolic syndrome management in prediabetes/T2DM.
🚭 Smoking cessation and alcohol moderation reduce peripheral nerve injury.
💉 Cardiovascular risk management: BP & lipid control support nerve health.

🔎 Detection & Screening (NICE 2024)

📅 Annual foot and neuropathy screening: at T2DM diagnosis and 5 years after T1DM onset.
👣 10g monofilament test – predicts risk of foot ulceration/amputation.
🦶 Clinical exam: pinprick & temperature (small fibre), vibration & proprioception (large fibre).
🧪 Nerve conduction studies only for atypical features (rapid progression, asymmetric, motor predominant).
📋 Autonomic testing considered if symptomatic (postural hypotension, GI or genitourinary dysfunction).

📚 Types of Diabetic Neuropathy

Type	Clinical Features	Notes / Management
🦶 Distal Symmetric Polyneuropathy (DSPN)	“Glove & stocking” burning, tingling, numbness; loss of vibration & temperature sensation; foot ulcer risk.	💊 First-line: Duloxetine or Pregabalin (NICE). Alternatives: Gabapentin, low-dose TCAs. 👟 Daily foot inspection, protective footwear, podiatry referral.
🧠 Autonomic Neuropathy	Postural hypotension, resting tachycardia, gastroparesis, diarrhoea, erectile dysfunction, gustatory sweating, urinary retention.	🫀 OH: salt/fluid loading, Midodrine, Fludrocortisone. 🍽️ Gastroparesis: Metoclopramide/domperidone. 💩 Diarrhoea: Loperamide/codeine. 🍆 ED: PDE-5 inhibitors.
🦵 Proximal Neuropathy (Diabetic Amyotrophy)	Unilateral thigh/hip pain, quadriceps wasting, difficulty rising from chair.	Immune-mediated microvasculitis. Analgesia, physiotherapy, glucose optimisation. Spontaneous improvement over months.
🎯 Focal Neuropathy	Cranial nerve palsies (CN III, IV, VI → diplopia/ptosis), facial nerve palsy, limb mononeuropathies. Often painful.	Self-limiting (weeks–months). Supportive care, exclude compressive lesions.
🌀 Mononeuritis Multiplex	Patchy motor/sensory deficits, can involve cranial nerves.	Self-limiting; rarely steroids or IVIG if severe or progressive.

🛠️ Overall Management (NICE 2024)

🎯 Individualised glycaemic targets – tight but safe control; consider age, comorbidities, frailty.
💊 Painful neuropathy: Duloxetine or Pregabalin first-line; alternatives Gabapentin or low-dose TCA.
🚫 Avoid long-term opioids unless refractory, under specialist supervision.
👟 Lifestyle: exercise, weight optimisation, smoking/alcohol reduction.
👣 Foot care: daily inspection, chiropody, protective footwear; podiatry referral for ulceration or high-risk feet.
📅 Regular review of autonomic symptoms and cardiovascular risk factors.

📝 Teaching Pearls

✅ Always exclude reversible causes (B12, TSH, alcohol) before diagnosing diabetic neuropathy.
👣 Monofilament testing is the cornerstone of foot ulcer prevention.
⚡ Autonomic neuropathy is under-recognised – ask specifically about dizziness, GI symptoms, and ED.
🧠 Mnemonic: “PA-PF” = Peripheral, Autonomic, Proximal, Focal neuropathies.

📚 References

🎯 Example OSCE Cases

Case 1: 55-year-old man with T2DM, burning feet worse at night; monofilament absent. 👉 DSPN. Start Duloxetine, reinforce foot care & podiatry referral.

Case 2: 60-year-old woman faints on standing; postural BP drop 30 mmHg. 👉 Autonomic neuropathy. Begin salt/fluid loading, consider Midodrine.

Case 3: 65-year-old man with sudden diplopia; CN VI palsy. 👉 Focal cranial neuropathy. Supportive care; usually resolves in weeks.

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Diabetic neuropathy