In obstructive urinary tract disorders, the Valsalva maneuver can be performed in order to ease micturition. Among other things, the maneuver leads to complex vascular reactions and increases the systemic blood pressure. These vascular changes pose a serious stressor to the vessel wall and ruptures of small arteries have been anecdotically described in literature. Herein, we present a case of a patient referred to a thoracic surgeon with a huge mediastinal hematoma. Diagnostic work-up revealed a spontaneous rupture of the left inferior thyroid artery due to repetitive Valsalva maneuver.