Toxic myopathies

The incidence of toxic myopathies is increasing. This may be in part related to the large number of readily available compounds, including therapeutic drugs, drugs of abuse, and environmental toxins, that are potentially toxic to muscle. Toxic myopathy should be included in the differential diagnosis of anyone exposed to any of the compounds discussed here who develops weakness, wasting, and an elevated CK with or without pain. Specific EMG and muscle biopsy features are seen in many of these conditions and may be extremely helpful in making the diagnosis. Recognition of these myopathies is crucial because most are reversible upon discontinuation of exposure to the toxin.