[en] We describe the case of a 29 year old patient who presented severe myalgias and asthenia for 3 months. First biological assessment revealed muscular lysis and raised transaminases. The following complementary screening showed major hypothyroidism with the presence of anti-microsomes antibodies, a carpian canal syndrome and a left ventricular systolic dysfunction. A diagnosis of hypothyroidic rhabdomyolysis consecutive to a Hashimoto disease was then mash. Patient was treated by hormonal thyroid substitution with a progressive improvement of muscular symptoms to complete recovery, and a concomitant normalization of cardiac and thyroid functions.