II. TOXIC DISORDERS
A. General Categories
Toxins include: heavy metals, certain poisons, endogenous products of metabolism,
organic compounds, drugs (of addiction and/or therapy) and anesthetics.
Occasionally, the mechanism of action is clear, as in the anoxic poisons,
carbon monoxide and cyanide. More often the relationship of biochemical
and morphological lesions is obscure. Alcohol, for example, is a depressant
drug which may cause nervous system and muscle pathology directly or through
metabolites.
On the other hand, the profound nutritional deprivations which generally
accompany alcoholism also cause nervous system pathology. In the case of
alcoholism, the latter effects appear to be more important and will therefore
be discussed as problems of nutritional etiology.