unconsciousness /unkon″shəsnəs/ , a state of complete or partial unawareness or lack of response to sensory stimuli as a result of hypoxia caused by respiratory insufficiency or shock; from metabolic or chemical brain depressants such as drugs, poisons, ketones, or electrolyte imbalance; or from a form of pathological brain conditions such as trauma, seizures, cerebrovascular accident, brain tumor, or infection. Various degrees of unconsciousness can occur during stupor, fugue, catalepsy, and dream states. See also coma.