Thallium and arsenic poisoning in a small midwestern town.

Thallium and arsenic have been used as a means of criminal poisoning. Although both manifest characteristically with peripheral neuropathies, thallium is associated with alopecia and arsenic with gastrointestinal symptoms. We describe the symptoms, physical findings, diagnostic test results, and outcomes in a group of men poisoned with thallium and arsenic. Seven patients had evidence of elevated thallium levels, and 2 patients had elevated arsenic and thallium levels. The most commonly reported symptoms included myalgias, arthralgias, paresthesias, and dysesthesias. Five patients developed alopecia. All patients with symptoms and peripheral neuropathies had characteristic blackening of their hair roots. Initially treated with dimercaptosuccinic acid, patients were switched to multiple-dose activated charcoal after testing revealed thallium poisoning. By 6 months, all patients' symptoms and peripheral neuropathies improved, but 5 patients had ongoing psychiatric problems. Thallium remains a means of criminal poisoning and should be considered in any patient with a rapidly progressing peripheral neuropathy with or without alopecia.