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15 - 08 - 1999
I found something very interesting: http://www.hem.com/statox/stox712.htm this is the text: TOXIC PERIPHERAL NEUROPATHIES COMMENTS CLINICAL PRESENTATION BIOLOGICAL SAMPLING REFERENCES ------------------------------------------------------------------------ COMMENTS Peripheral neuropathies are of three types: First, is that of a rapid onset, usually sensory, sometimes caused by mercury or adriamycin. The second type is rapid onset, primarily motor. Can be caused by buckthorn poisoning. The third type is gradual onset, stocking glove with a mixed motor and sensory component, and this comprises a majority of the chemicals. This classification is probably the most helpful from a clinical perspective (Schaumburg and Spencer, 1979). CLINICAL PRESENTATION In sensory peripheral neuropathy there may be a decreased sensation to pain with a sharp object such as a pin. DeGowin suggests running the stroke from the non-sensitive to the sensitive skin, having the patient indicate a change. Temperature discrimination may be lost when tactile sense is still present. Proprioceptive sense, specifically vibratory sense, may be lost with sensory peripheral neuropathy. Motor peripheral neuropathy may be focal and in a nerve root distribution. If there is disease of the pyramidal track, there may be hyperactive reflexes. In its extreme clonus, and a positive babinski reflex (DeGowin and DeGowin, 1969). Differential diagnosis of peripheral neuropathy include the following: chronic arsenic exposure; benzene; carbon monoxide; chlorine; phenocoll; dinitrophenols; ethambutol; ethanol; goldsalts; herbicides; hexane; hydrogen sulfide; isoniazid; lead; mercury; methanol; methaqualone; narcotics; nicotine; paralytic shellfish; thallium (Noji and Kelen, 1989). Additionally, thalidomide monomers, carbon disulfide, hexane, methyl- and butyl-ketone, organophosphates (tocp, leptophos, poly-chlorinated byphenals, pcb's) (Schaumburg and Spencer, 1979). Lead can cause a peripheral neuropathy and a sensory neuropathy when the lead levels reach up to 60 g% (Araki and Honma, 1976; Ashby, 1980; Seppalainen et al, 1975). N-hexane and methyl n-butyl-ketone have been reported to cause peripheral neuropathy (Billmaier et al, 1974; Herskowitz et al, 1971; Iida et al, 1969). These peripheral neuropathies are usually symmetric and sensory motor. BIOLOGICAL SAMPLING In electromyography (EMG) and nerve conduction studies (NCS), the majority of toxic neuropathies are normal, therefore a normal does not rule out a toxic neuropathy (Sullivan and Krieger, 1993). However, if there is a myopathy that develops, the electromyography may be abnormal. Fibrillation and high frequency potentials in organophosphate induced neuropathy may have EMG and NCS abnormalities (Sullivan and Krieger, 1992). Serum lead levels may be obtained when there is a question of such exposure. Twenty-four hour urine arsenic levels may be helpful. Sural nerve biopsy may be helpful in diagnosing toxic neuropathy. REFERENCES Araki S, Honma T: Relationships between lead absorption and peripheral nerve conduction velocities in lead workers. Scand J Work Environ Health 4:225, 1976. Ashby J: A neurological and biochemical study of early lead poisoning. Br J Ind Med 37:133, 1980. Billmaier D, Yee H, Allen H, et al: Peripheral neuropathy in a coated fabrics plant. J Occup Med 16:665, 1974. DeGowin E, DeGowin R: Bedside Diagnostic Examination. The MacMillan Company, 1969. Herskowitz A, Ishii N, Schaumburg H: n-Hexane neuropathy. A syndrome occurring as a result of industrial exposure. N Engl J Med 285:82, 1971. Iida M, Yamamura Y, Sobue I: Electromyographic findings and conduction velocity on n-hexane polyneuropathy. Electromyography 9:247, 1969. Noji E, Kelen G: Manual of Toxicologic Emergencies. Year Book Medical Publishers, Inc., 1989; page 209. Schaumburg H, Spencer P: Toxic Neuropathies. Neurology 29:431, 1979. Seppalainen A, Tola S, Hernberg S, et al: Subclinical neuropathy at "safe" levels of lead exposure. Arch Environ Health 30:180, 1975. Sullivan J, Krieger G: Hazardous Materials Toxicology. Williams & Watkins, Baltimore, Maryland; 1992. Sullivan J, Krieger G: Hazardous Materials Toxicology. Williams & Watkins, Baltimore, Maryland; 1993.