Peripheral Neuropathy: Symptoms, Patterns, and Clinical Evaluation

Peripheral neuropathy encompasses damage to peripheral nerves — sensory, motor, autonomic — singly (mononeuropathy), in multiple sites (mononeuropathy multiplex), or diffusely (polyneuropathy).

Common Symptom Clusters

• Sensory: Numbness, tingling, pins‑and‑needles, burning, shooting pain, allodynia (pain from light touch), loss of vibration/proprioception.
• Motor: Weakness, atrophy, fasciculations, cramps, foot drop, reduced reflexes.
• Autonomic: Orthostatic hypotension, gastroparesis, diarrhea/constipation, urinary retention/incontinence, anhidrosis, erectile dysfunction.

Typical Patterns

• Length‑dependent (stocking‑glove): Distal symmetric polyneuropathy — most common (diabetes, idiopathic, toxins, B12 deficiency).
• Focal/mononeuropathy: Median (carpal tunnel), ulnar (cubital tunnel), peroneal (foot drop), radial.
• Multifocal: Vasculitis, sarcoidosis, Lyme, multifocal motor neuropathy.
• Autonomic‑predominant: Pure autonomic failure, diabetic autonomic neuropathy, amyloid.

Diagnostic Workup

1. History: onset, progression, distribution, risk factors (diabetes, alcohol, chemo, meds, family).
2. Neurologic exam: sensory modalities, strength, reflexes, autonomic signs.
3. Labs: glucose/HbA1c, B12/folate, TSH, SPEP/IFE, ANA/ESR, HIV, Lyme, heavy metals.
4. Electrodiagnostics: NCS/EMG — demyelinating vs. axonal, distribution, severity.
5. Skin biopsy (intraepidermal nerve fiber density) for small‑fiber neuropathy.
6. Genetic testing if hereditary suspected (CMT, familial amyloid).

Management Principles

• Treat underlying cause (glucose control, B12 replacement, alcohol cessation, immunosuppression for autoimmune).
• Symptomatic pain control: gabapentinoids, SNRIs (duloxetine), TCAs, topical capsaicin/lidocaine.
• Physical/occupational therapy for weakness, balance, orthotics.
• Autonomic: compression stockings, midodrine/fludrocortisone, dietary modification.
• Foot care education (daily inspection, proper footwear) for insensate feet.

Early diagnosis and etiology‑specific treatment improve outcomes and prevent disability.