Exploration des myopathies toxiques : de l'anamnèse aux méthodes de pharmacogénomique

Toxic myopathies are the result of exogenous perturbations of the structure and/or the function of muscles. Depending on the particularities of each perturbation, different exploration methods can be used. The large number of pathologies that can mimic toxic myopathies makes the anamnesis an essential step in diagnosis. The anamnesis can identify the medical and exposure histories as well as the pre-existing diseases which are essential elements to guide the clinician. Early assessment of the distribution of muscle damages and their degree of severity facilitates the treatment and exploration of affected areas. Biological assessments are of invaluable help because of their availability and fastness. Other means allow further exploration. Electromyography, medical imaging and magnetic resonance spectrometry are very useful to build the diagnosis and to evaluate more precisely the extent of muscle damages. The use of muscle biopsy is more limited because of its invasiveness. Some myopathies require more sophisticated techniques such as contracture tests. Toxicological screening in acute myopathies allows more adapted management of patients. Immunological exploration may reveal auto-antibodies (anticholinergic receptors or anti-HMG-CoA reductase) that could explain the persistence of myopathy after the eviction of the incriminated agent. Genetic susceptibilities to some xenobiotics can be identified by pharmacogenomic techniques. These technologies offer future solutions in the adaptation of potentially myotoxic drug therapies for each patient.