Isoniazid intoxication. Light and electron microscopic findings in muscle and sural nerve biopsies.

This study indicates the cellular and ultrastructural changes of the thigh muscle and sural nerve biopsies of a patient intoxicated as a result of isoniazid intake for tuberculosis treatment. The observation of the relative degradation of myelination and fibre type II groups was apparent. The regular concentric layers of the myelin sheath were destroyed.