Acute thallium poisoning: Toxicological and morphological studies of the nervous system

Abstract

Nine days following ingestion of 5 to 10 gm of thallium nitrate, a young man died with severe cranial and peripheral neuropathy, anuria, and heart failure. Ultrastructural examination of nerves obtained on days 7 and 9 demonstrated axonal degeneration with secondary myelin loss. Axons were swollen and contained distended mitochondria and vacuoles. Thallium levels in more than twenty organs and body fluids ranged from below 1.0 to 178 microgram/gm; concentrations in twenty areas of the nervous system ranged from 29 to 140 microgram/gm. The highest brain levels of thallium were found in gray matter. In the thalamus, 87% of the thallium was present in cell sap. Tissue concentrations of thallium did not parallel those reported for potassium, suggesting that thallium distribution differs from potassium distribution in human beings.

Heavy metal poisoning: management of intoxication and antidotes

“…They typical reveal a sensorimotor axonopathy with the severity of neuropathy correlating with the severity of other symptoms and findings. In cases of severe poisoning, a nerve biopsy may reveal Wallerian degeneration with axonal destruction and secondary myelin loss, although these findings are not specific to thallium [189,202,203].…”

Environmental Toxic Neuropathies

“…Thallium enters cells through potassium channels, substitutes for it in reactions, and can compete with potassium for sodium potassium ATPase [ 31,32 ] . The substitution for potassium, however, may not be the mechanism of its toxicity.…”

Medication and Toxin-Induced Peripheral Neuropathy

“…Pathological studies reveal a distal axonopathy of large, myelinated sensory axons, with swollen mitochondria. 59 Recovery is prolonged and often incomplete.…”