Myelopathy among zinc-smelter workers in Upper Silesia during the late 19th century

Zinc-induced myeloneuropathy was recently (re)discovered and its pathophysiology elaborated as resulting from secondary copper deficiency. However, myelopathy was a recognized problem among European zinc-smelter workers in the late 19th century, although these early reports have been overlooked in recent studies and reports. The purpose of this article is to translate and review German-language reports of myelopathy among zinc-smelter workers in Upper Silesia (now southern Poland) by Schlockow from the 1870s. Disease manifestations among zinc-smelter workers developed after sustained zinc exposure over many years. The earliest symptoms were sensory and included paresthesias, dysesthesias, allodynia, and formication in the lower extremities, particularly the feet. Workers ultimately developed a clinical picture resembling subacute combined degeneration of the spinal cord with a spastic-ataxic gait with prominent proprioceptive impairment, sensory disequilibrium, and rombergism.