Diabetic Neuropathy

Hallmark and Atypical Symptoms

Classic Symptoms:

• Numbness, tingling, and pain, primarily in the toes and feet.

• Sensory changes begin at toes, progressing to calves, then hands (nerve length-dependent, with proximal spread).

• Symptoms present at rest but improve with mobility.

• Symmetrical and slow progression over time.

Atypical Symptoms:

• Calf pain greater than foot pain, worsens with movement (often linked with Peripheral Vascular Disease - PVD).

• Acute onset, asymmetry, motor symptoms predominant over sensory, with symptoms in proximal extremities more than distal (non-length dependent).

Neuropathic Arthropathy / Charcot Foot

• Lack of proprioception leading to ligament laxity, instability, and increased risk of minor trauma

• Progressive degenerative changes in joint architecture

• Presents as swelling, redness, warmth, with a history of trauma or overuse

• Relatively painless despite significant deformity and abnormal weight-bearing

• Can result in fractures, deformity, and ulceration

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History

• Longstanding diabetes with poor glycemic control.

• Presence of other cardiovascular risk factors (e.g., smoking, hyperlipidemia, hypertension).

• Duration and severity of diabetes directly correlate with neuropathy risk.

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Clinical Features of Peripheral Neuropathy

Peripheral Neuropathy Symptom Score:

• 1 point for each symptom occurring a few times a week for the past 2 weeks.

• Symptoms: Unsteadiness, burning/aching/tenderness, prickling, numbness.

• Scoring system for neuropathy symptoms (assign 1 point for symptoms that occur a few times per week over the past 2 weeks):

  • 1 - Unsteadiness

  • 2 - Burning, aching, tenderness

  • 3 - Prickling

  • 4 – Numbness

• Score ≥ 1 indicates polyneuropathy

Peripheral Neuropathy Examination:

• Reduced ankle tendon reflexes

• Loss of 10g monofilament pressure sensation.

• Loss of vibration perception.

• Loss of pinprick pain sensation.

Charcot Neuropathy

• Acute: swollen, warm, red foot with minimal pain despite significant structural damage

• Chronic: deformity such as “rocker bottom” foot due to bone collapse and progressive joint destruction

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Diagnosis

• Imaging for Charcot Neuropathy

  • X-rays may show osteolysis, fractures, and deformity, especially in later stages

  • MRI or nuclear imaging can confirm stress fractures and soft tissue involvement, as plain radiographs may miss early changes

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Management

Non-Pharmacological:

• Well-fitting footwear.

• Daily self-examination of feet.

• Control of diabetes and cardiovascular risk factors.

• Regular podiatry reviews.

• Referral to high-risk foot clinics if necessary.

• Surgical referral for vascular assessment if warranted.

Pharmacological:

• Amitriptyline 25 mg at night, up to 150 mg as needed.

• Duloxetine 60 mg daily, may increase to 60 mg twice daily.

• Pregabalin 75 mg twice daily, up to 300 mg daily if needed.

• Topical nitrate spray for localized pain (not in ETG, but referenced in RACGP guidelines).

Note: Treatment options align closely with management strategies for fibromyalgia.

Charcot Foot - A Medical Emergency

• Requires a multidisciplinary high-risk foot team

• Management options:

  • Offloading with a total contact cast or Charcot restraint orthotic walker to prevent further weight-bearing injury

  • Antibiotics if cellulitis is present

  • Optimal diabetic control to prevent progression

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Differential Diagnosis for Neuropathy

General Neuropathy:

• Diabetic neuropathy.

• Prolonged alcohol use.

• Peripheral arterial disease (PAD).

• B12 deficiency.

• Hypothyroidism.

• Chronic kidney disease (with peripheral oedema).

• Multiple myeloma.

• Idiopathic (25% cases).

• Restless legs syndrome.

• Raynaud's phenomenon.

Unilateral Neuropathy:

• L5/S1 nerve root compression (back pain with radiation).

• Chronic regional pain syndrome (often post-trauma).

• Morton's neuroma (aggravated by tight shoes).

• Tarsal tunnel syndrome (compression of posterior tibial nerve).

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Notes

• Diabetic neuropathy is progressive and managing blood glucose levels can slow its progression.

• Regular monitoring and lifestyle modifications are crucial.

• Early recognition and management can prevent complications, especially in foot care to avoid ulcers and infections.

Pathophysiology of Charcot Foot:

• Charcot neuropathy is attributed to repeated minor trauma and loss of protective sensation, which leads to joint destruction and bone resorption.

• The affected foot is often warm, red, and swollen, but relatively painless.

Patient Education:

• Emphasize the importance of regular foot checks and immediate reporting of new symptoms (e.g., redness, warmth, or swelling in feet).

• Discuss the role of glycaemic control in preventing neuropathy progression