shock

In medicine, circulatory failure marked by a sudden fall of blood pressure and resulting in pallor, sweating, fast (but weak) pulse, and sometimes complete collapse. Causes include disease, injury, and psychological trauma.

In shock, the blood pressure falls below that necessary to supply the tissues of the body, especially the brain. Treatment depends on the cause. Rest is needed, and, in the case of severe blood loss, restoration of the normal circulating volume.