[Primary lesions caused by explosions]. / Lesiones primarias por explosión.

The lesions produced by the expansive wave are characteristic of severe injury produced by explosion. This type of injury is being classified as primary lesion. We report a 28 years old male patient who suffered amputation of both lower extremities associated with hypovolemic shock. The patient presented primary tympanic perforation and pneumothorax after initiation of mechanical ventilation at positive pressure. In the discussion section we analyze the physical mechanisms leading to this primary lesion and we indicate the organs most commonly affected. We rise general considerations dealing with the management of these patients and we remark the advantages of a coordinated medical attendance policy.