RESUMEN
The diagnosis of peripheral neuropathy is not difficult but knowing the cause of peripheral neuropathy is a difficult problem. This, authors had classified peripheral neuropathy into motor, sensory, monouritis multiplex or mixed neuropathy with or without autonomic nervous system involvement. Painful sensory neuropathy with autonomic nervous system involvement is mostly due to diabetes mellitus, amyloidosis, toxins like thallium and neuropathy associated with malignancies. Nine patients diagnosed clinically and by measurement of urine and plasma levels of thallium as thallium poisoning were undergone a full noninvasive autonomic function tests. The study showed that autonomic dysfunction was present in all cases and the parasympathetic nervous system was more vulnerable to be involved than the sympathetic nervous system