Peripheral Nerve Disorders

Peripheral nerve disorders (peripheral neuropathy) are diseases of the nerves that run outside the brain and spinal cord. They cause numbness, tingling, pain, weakness, or autonomic problems depending on which nerves are affected. In India, diabetic neuropathy and vitamin B12 / other nutritional deficiencies are by far the commonest causes.

Symptoms

• Sensory — numbness, tingling ("pins and needles"), burning, electric pain; often starts in feet then hands (glove-and-stocking).
• Motor — weakness, wasting, cramps, dropping objects, tripping.
• Autonomic — dizziness on standing, digestive issues, bladder changes, sweating changes, sexual dysfunction.
• Can be acute (Guillain-Barré) or chronic (diabetes, B12 deficiency, leprosy).

Causes common in India

• Diabetes — the single commonest cause of chronic neuropathy.
• Vitamin B12 deficiency — especially in vegetarians; very common, easily treated.
• Vitamin D, folate, thiamine deficiencies.
• Alcohol — directly toxic + associated thiamine deficiency.
• Leprosy — still occurs in India; characteristic peripheral nerve thickening, skin patches; fully treatable with multi-drug therapy (free under national programme).
• Hypothyroidism, kidney disease.
• HIV, hepatitis, TB treatment side-effects.
• Chemotherapy.
• Inherited (Charcot-Marie-Tooth) and autoimmune (CIDP, Guillain-Barré).
• Compression — carpal tunnel, sciatica (covered on own pages).

Red flags — see a Health Expert urgently

• Rapid onset weakness ascending from legs — Guillain-Barré; dial 112.
• Weakness with bladder/bowel changes — spinal cord, not peripheral.
• Rapidly progressive weakness.
• Sudden facial weakness with limb weakness — brainstem.
• Fever, rash, joint pain with neuropathy — vasculitis work-up.
• Severe pain unmanageable with simple measures.

Evaluation

• Blood tests — sugar, HbA1c, B12, folate, TSH, kidney, liver, HIV, vasculitis screen as indicated.
• Nerve conduction studies + EMG.
• Nerve biopsy — selected cases.
• Skin biopsy for small-fibre neuropathy.
• Evaluate for leprosy — palpate peripheral nerves, look for skin patches — in India, don't miss it.

Treatment

• Treat the cause — optimal diabetes control, B12/other vitamin replacement, stop alcohol, multi-drug leprosy therapy, treat thyroid/HIV/kidney disease.
• Nerve-pain medicines (specific classes under specialist guidance) — for painful neuropathy.
• Foot care — crucial in diabetic and leprosy neuropathy; see Diabetic Foot and Leprosy pages.
• Physiotherapy, occupational therapy, orthotics — where weakness is present.
• Regular monitoring — progression, complications, response to treatment.