panic attack

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The sudden onset of intense anxiety, characterized by feelings of intense fear and apprehension and accompanied by palpitations, shortness of breath, sweating, and trembling.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A sudden period of intense anxiety, mounting physiological arousal, fear, stomach problems and discomfort that are associated with a variety of somatic and cognitive symptoms.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a sudden attack of fear