Acute thallium poisoning: toxicological and morphological studies of the nervous system.

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.