A person presents to OPD with tremors, visual hallucinations after 2 days history of alcohol cessation.  Diagnosis is:
Ref. Oxford textbook of Psychiatry. Page. 572
 
 Delirium Tremens / Alcohol Withdrawal Delirium (AWD):
Most severe form of ethanol withdrawal manifested by,
Mechanism: 

Altered mental status (Global confusion)
Autonomic hyperactivity (Sympathetic overdrive)

Alcohol abuse affects neurotransmitter systems in brain mainly by,

Loss of GABA inhibitory mechanism - Reduces chloride ion influx.
Alcohol acts as NMDA receptor antagonist - Withdrawal increases the excitatory neurotransmitter.

The clinical manifestations of ethanol withdrawal are combination effects of GABA & NMDA receptor activity.
Thus causing tremors, diaphoresis, tachycardia, anxiety & in severe cases Seizure.
Korsakoff’s psychosis
Delirium tremens
Wernicke encephalopathy
Alcoholic hallucinosis