Clinical features of toxic neuropathies
| Neuropathy phenotype | Toxic causes to consider |
| Sensory predominant | Commonly cause predominant sensory ataxia: Mercury, nitrous oxide, acrylamide Pyridoxine (vitamin B6), platinum compounds, brentuximab vedotin, amiodarone |
| Other causes of sensory predominant neuropathy: Alcohol, cadmium, n-hexane/glue-sniffing, allyl chloride, carbon disulphide, ethylene oxide Taxanes, bortezomib, thalidomide, BRAF/MEK inhibitors, leflunomide, linezolid, metronidazole, calcineurin inhibitors, isoniazid, ethambutol, triazole antifungals, amiodarone, phenytoin, colchicine, chloroquine, levodopa/carbidopa intestinal gel, fluoroquinolones | |
| Can involve significant distal motor weakness | Nitrous oxide, lead, arsenic, thallium, n-hexane/glue-sniffing, organophosphates Vinca alkaloids, BRAF/MEK inhibitors, dapsone, nitrofurantoin, disulfiram, amiodarone |
| Predominant neuropathic pain | Alcohol, mercury, thallium, ciguatoxin Taxanes, bortezomib, thalidomide, linezolid, metronidazole, nitrofurantoin, disulfiram, cotrimoxazole |
| Acute/subacute sensorimotor neuropathy (‘GBS like’) | Arsenic, thallium, seafood toxins (saxitoxin, tetradotoxin), diethylene glycol, n-hexane/glue-sniffing (if acute high doses) Immune checkpoint inhibitors, tumour necrosis factor inhibitors, BRAF/MEK inhibitors, calcineurin inhibitors, nitrofurantoin, bortezomib (rarely), amiodarone (rarely) |
| Extraneural features | Toxic causes to consider |
| Encephalopathy | Alcohol, lead (mainly in children), arsenic, mercury, n-hexane/glue-sniffing, industrial agents (acrylamide, carbon disulphide, diethylene glycol, ethylene oxide) Metronidazole, disulfiram, phenytoin |
| Tremor | Mercury Calcineurin inhibitors, amiodarone, phenytoin |
| Optic neuropathy | Nitrous oxide, lead, mercury, thallium Vincristine, calcineurin inhibitors, linezolid, ethambutol, isoniazid, amiodarone, chloroquine, dapsone, disulfiram |
| Myelopathy | Nitrous oxide |
| Myopathy | Taxanes, immune checkpoint inhibitors, amiodarone, colchicine, chloroquine |
| Gastrointestinal disturbance | Lead, arsenic, thallium, seafood toxins, organophosphates |
| Renal failure | Lead, mercury, cadmium, diethylene glycol Calcineurin inhibitors |
| Anaemia | Chemotherapy drugs, lead (microcytic anaemia, basophilic stippling), arsenic, nitrous oxide (megaloblastic anaemia) |
| Mees’ lines | Arsenic, thallium |
| Hyperkeratosis | Arsenic, thallium |
GBS, Guillain-Barre syndrome; MEK, mitogen-activated protein kinase kinase (or MAP2K).