Table 1:

Differential diagnoses for subtypes of polyneuropathy9

Subtype	Differential diagnoses
Distal symmetric polyneuropathy	Diabetes mellitus Alcohol Chronic kidney disease Vitamin B₁₂ deficiency	Adverse effect of medications and chemotherapy Amyloidosis MGUS (IgG and IgM) HIV
Acute-to-subacute polyneuropathy	Guillain–Barré syndrome CIDP with acute onset Vasculitis (primary or secondary)^* Critical illness polyneuropathy Lymphoproliferative disease	Sarcoidosis Organophosphate exposure Diphtheria Porphyria
Motor-predominant polyneuropathy	CIDP Multifocal motor neuropathy Hereditary motor sensory polyneuropathy (e.g., Charcot–Marie–Tooth disease) Hereditary motor neuropathies	Porphyria Lead toxicity Diphtheria Adverse effect of medications (e.g., dapsone)
Mononeuritis multiplex	Vasculitis (primary or secondary) MADSAM Multifocal motor neuropathy Amyloidosis Sarcoidosis	Inflammatory bowel disease Celiac disease HNPP Diabetes mellitus
Autonomic neuropathy	Diabetic autonomic neuropathy Alcohol-related neuropathy Amyloidosis Autoimmune autonomic ganglionopathy Adverse effect of medications (amiodarone, vincristine, cisplatin, paclitaxel)	Sjögren syndrome HIV Vitamin B₁₂ deficiency Heavy metal toxicity (lead, thallium, mercury) Hereditary sensory and autonomic neuropathy
Isolated small-fibre polyneuropathy	Diabetes mellitus HIV Hepatitis C (with or without cryoglobulinemia) Cryoglobulinemia Amyloidosis (familial or sporadic) Fabry disease Ehlers–Danlos syndrome	Hemochromatosis Sodium channelopathies (SCN9A, SCN10A) Sjögren syndrome Celiac disease Hypertriglyceridemia Alcohol

Note: CIDP = chronic inflammatory demyelinating polyradiculoneuropathy, HIV = human immunodeficiency virus, HNPP = hereditary neuropathy with liability to pressure palsies, Ig = immunoglobulin, MADSAM = multifocal acquired demyelinating sensory and motor neuropathy, MGUS = monoclonal gammopathy of undetermined significance.
↵* Common primary vasculitides with neuropathy include microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis, granulomatosis with polyangiitis, polyarteritis nodosa, and Behçet disease. Systemic (secondary) vasculitides with neuropathy are less common and are associated with another cause. Examples include connective tissue diseases (such as systemic lupus erythematosus, rheumatoid arthritis, Sjögren syndrome), infection (hepatitis B and C) and cryoglobulinemia.