Severe Withdrawal Complications

Severe withdrawal complications occur in a minority of cases and include seizures, delirium and hallucinations. Early treatment of mild symptoms can prevent progression but many patients only present with established severe withdrawal.

Alcohol Withdrawal Seizures

Alcohol withdrawal seizures are usually generalised (tonic-clonic) seizures. They occur as blood alcohol levels fall, typically within 6 to 24 hours after the last drink is consumed, and can occur even if the blood alcohol level is high (for example, greater than 20 mmol/L) in people with severe alcohol dependence. (Figure 8.1)

The prevalence of alcohol-withdrawal seizures is estimated at 2 - 9 % of alcohol dependent people. People who have experienced an alcohol withdrawal seizure are more likely to experience further seizures in subsequent alcohol withdrawal episodes. The risk of seizure recurrence within 6 to 12 hours is estimated at between 13 and 24 per cent in untreated patients.

Alcohol Withdrawal Delirium

The features of alcohol withdrawal delirium (also known as delirium tremens or DTs) are disturbance of consciousness and changes in cognition or perceptual disturbance. The terms ‘alcohol withdrawal delirium’ and ‘delirium tremens’ can be used interchangeably. Alcohol withdrawal delirium is an acute organic brain syndrome characterised by confusion and disorientation, agitation, hyperactivity and tremor.

Alcohol withdrawal delirium typically commences 2 to 3 days after ceasing drinking, and usually lasts for a further 2 to 3 days, although it can persist for weeks. The incidence of alcohol withdrawal delirium in unmedicated alcohol dependent patients averages 5 per cent, although the incidence is much lower with effective treatment of alcohol withdrawal. Early studies of delirium tremens reported mortality rates as high as 15 per cent; however, mortality rates have fallen with advances in management to less than 1 per cent.


Some patients experience hallucinations or other perceptual disturbances (for example, misperceptions) at any stage of the alcohol withdrawal phase. Hallucinations may be visual, tactile or auditory, and may be accompanied by paranoid ideation or delusions, and abnormal affect (agitation, anxiety, dysphoria). 

FIGURE 8.1: Alcohol withdrawal syndrome progression

Figure 8.1