Is a short-lived, but occasionally life-threatening, toxic-confusional state with accompanying somatic disturbances.
It is usually a consequence of absolute or relative withdrawal of alcohol in severely dependent users with a long history of use.

Onset usually occurs after withdrawal of alcohol. In some cases the disorder appears during an episode of heavy drinking. Prodromal symptoms typically include insomnia, tremulousness, and fear. Onset may also be preceded by withdrawal convulsions.
The classical triad of symptoms includes clouding of consciousness and confusion, vivid hallucinations and illusions affecting any sensory modality, and marked tremor. Delusions, agitation, insomnia or sleep-cycle reversal, and autonomic overactivity are usually also present.

See the reference for more information.

World Health Organization. The ICD-10 Classification of mental and behavioral disorders: clinical descriptions and diagnostic guidelines. Internet. Accessed December 28, 2010.