Make the Diagnosis: Severe Alcohol Withdrawal Syndrome
Prior Probability of Severe Alcohol Withdrawal Syndrome
The incidence of alcohol withdrawal syndromes in hospitalized patients varies widely as a function of the patient population, care setting, and the reason for hospital admission. About one-half of patients who are long-term, heavy alcohol users will develop at least mild withdrawal symptoms when they stop drinking. The more significant symptoms of hallucinations occur in 2% to 8% of patients, with 10% of those symptomatic patients affected by seizures. Among patients admitted specifically for alcohol withdrawal, the incidence of severe alcohol withdrawal is 23% (95% CI, 20%-27%).
For those admitted to general medical units who are at risk for alcohol withdrawal (defined as an Alcohol Use Disorders Identification Test-Consumption [AUDIT-C] score > 8), the incidence of any alcohol withdrawal syndrome is 1.9% (95% CI, 1.2%-3.1%), though patients admitted with a blood alcohol level > 200 mg/dL, or a history of any drinking in the prior 30 days, have an incidence of 6.7% (4.6%-9.6%). Patients admitted after trauma are a particular concern because an accurate alcohol history may not be obtainable, but the overall incidence of severe alcohol withdrawal syndrome among consecutive trauma patients is only 0.40% (95% CI, 0.33%-0.48%).
Population of Hospitalized Patients Among Whom Alcohol Withdrawal Syndrome Should Be Considered
All hospitalized patients should be screened for at-risk or heavy drinking so that measures can be taken to lower the risk of severe alcohol withdrawal syndrome. A definition of at-risk or heavy alcohol use would be consumption of 4 drinks on any day or 14 drinks/week for men, or more than 3 drinks on any day or 7 drinks/week for women.1 When at-risk patients are identified, the Clinical Institute Withdrawal Assessment for Alcohol (CIWA) is used to measure the severity of withdrawal symptoms, and protocol that includes the administration of benzodiazepine prophylaxis has been associated with a reduced incidence of delirium tremens (–4.9 cases per 100 patients) and seizures (–7.7 seizures per 100 patients).2
Assessing the Likelihood of Alcohol Withdrawal Syndrome
A prior history of delirium tremens is the finding that is both studied best (3 studies) and that is associated with increased likelihood of delirium tremens (likelihood ratio [LR], 2.9; 95% CI, 1.7-5.2; see Table 105-1). A history of substance use disorders other than alcohol have been associated with increased risk of severe alcohol withdrawal syndrome (LR, 6.4; 95% CI, 1.2-34), but this risk factor was reported in only 1 high-quality study. The presence of a blood alcohol level > 200 mg/dL (LR, 3.5; 95% CI, 3.0-4.0) is associated with increased likelihood of any symptoms of alcohol withdrawal syndrome.
Table 105-1.Useful Findings for Assessing the Likelihood of Alcohol Withdrawal Syndrome