Clinical meaning
Advanced management of peripheral neuropathy requires distinguishing axonal from demyelinating patterns, length-dependent from non-length-dependent neuropathies, and identifying the underlying etiology among over 100 potential causes. Electrodiagnostic studies (nerve conduction velocity studies and electromyography) are the cornerstone of evaluation: axonal neuropathies show reduced amplitude with preserved conduction velocity, while demyelinating neuropathies show prolonged distal latencies, reduced conduction velocity, conduction block, and temporal dispersion. The NP must systematically evaluate metabolic (diabetes, B12, thyroid), toxic (alcohol, chemotherapy, heavy metals), inflammatory (CIDP, vasculitic neuropathy), infectious (HIV, Lyme, hepatitis C), hereditary (CMT), and paraneoplastic etiologies through targeted laboratory and electrodiagnostic testing.
Diagnosis & workup
Diagnostics & workup: - Nerve conduction studies (NCS) and electromyography (EMG) — distinguish axonal vs demyelinating pattern - HbA1c and 2-hour OGTT (diabetes/prediabetes screening) - Vitamin B12 and methylmalonic acid (MMA — more sensitive for B12 deficiency) - TSH (hypothyroid neuropathy) - SPEP/UPEP with immunofixation (paraproteinemia screening) - Hepatitis B/C and HIV serology - ESR, ANA, ANCA (vasculitic neuropathy) - Nerve biopsy for suspected vasculitis, amyloidosis, or CIDP when electrodiagnostics inconclusive - Skin punch biopsy for intraepidermal nerve fiber density (small fiber neuropathy)