Chapter 31
Alcohol Withdrawal
Diagnosis and Management
Alcohol Dependency and Alcohol Withdrawal Syndrome
Alcohol withdrawal syndrome (AWS) is defined by criteria listed in Box 31.1. Although overall mortality and morbidity due to AWS have steadily decreased with the advent of improved treatment and monitoring strategies, utilization of these strategies remains inconsistent. For instance, a considerable proportion (15% to 20%) of patients admitted to the hospital are alcohol dependent (as high as 39% in the ICU), yet studies show that only about half of these patients are initially identified as such by their physicians. Although this may in part be due to inaccurate self-reporting of true alcohol consumption, these data likely reflect lack of implementation of validated screening techniques for alcohol dependence. In addition, the decision process to give pharmacologic prophylaxis and the choice of which medication to use is not consistent or standardized. Although this is not widely appreciated, many patients who are alcohol dependent will not undergo alcohol withdrawal during hospitalization. In fact, only 5% to 7% of this patient population progress into AWS.
Neurophysiology and Physiology of Alcohol Withdrawal
Alcohol stimulates the brain’s main inhibitory neurotransmitter, gamma-aminobutyric acid (GABA), by activating the GABAA receptor, which is responsible for the depressant effects of alcohol on the central nervous system (CNS). With chronic alcohol consumption, GABA receptors become less responsive to the same dosage of alcohol, which causes tolerance to develop. Alcohol also binds to and inhibits N-methyl-d-aspartate (NMDA) receptors in the brain, which inhibit the release of the excitatory neurotransmitter glutamate. Similar to the effects on GABA receptors, chronic exposure to alcohol causes up-regulation of NMDA receptors, which also contributes to the development of tolerance.
Timing of Withdrawal Symptoms
The manifestations of alcohol withdrawal range from mild tremors to seizures and death. The first signs and symptoms may begin within 6 to 36 hours from the time of the last alcoholic drink. The first signs of minor withdrawal often include mild anxiety, headaches, diaphoresis, gastrointestinal (GI) upset, and tremulousness (see Box 31.1). Alcohol withdrawal—related seizures, which occur in ∼10% of patients, typically manifest as single or several brief generalized tonic-clonic seizures with short post-ictal periods within 6 to 48 hours after the last drink. Although status epilepticus may be caused by alcohol withdrawal, it is sufficiently rare that it should prompt a search for an alternate etiology. Hallucinations, both visual and auditory, occur typically between 12 to 48 hours after the last alcoholic drink. In ∼5% of patients, full delirium, agitation, extreme anxiety/fear, and progression to delirium tremens may occur 48 to 96 hours after the last drink. At this stage of withdrawal, patients may also exhibit vital sign instability, most notably tachycardia and hypertension. Although these time frames are general guidelines, in a given patient the timing and severity of withdrawal may vary significantly. Therefore, monitoring the progression of symptoms and signs is critical for making appropriate treatment decisions in individual patients.
Diagnostic Screening Tools
The diagnosis of AWS is clinical and based on the patient’s history plus a high index of suspicion from the presenting signs and symptoms. However, standardized screening tools can be helpful for identifying patients at risk for alcohol-related disorders and hence for AWS. One commonly used tool is the 4-question CAGE questionnaire (Box 31.E1). Other well validated and rapid screening tools include the 3-question AUDIT (Alcohol Use Disorders Identification Test) (http://www.hepatitis.va.gov/provider/tools/audit-c.asp#S1X), the 10-question AUDIT (http://whqlibdoc.who.int/hq/2001/WHO_MSD_MSB_01.6a.pdf), and the NIDA-Modified Alcohol, Smoking, and Substance Involvement Screening Test (NM ASSIST) (www.drugabuse.gov/nmassist/). The last is a convenient web-based interactive tool.
Once a patient at high-risk for alcohol withdrawal has been identified, the patient should be monitored closely for the development of signs and symptoms of AWS. The most widely studied and used scoring tool is the Revised Clinical Institute Withdrawal Assessment for Alcohol scale (CIWA-Ar) (Box 31.E2). This 10-question assessment tool combines both patient responses to questions related to orientation, nervousness, and hallucinations and observations made by medical personnel to complete the score. In addition to being a tool to monitor the emergence of AWS, because the CIWA-Ar score tracks the severity of the withdrawal (see Box 31.E2), it is also used to guide the titration of medicines used to treat AWS. Although the CIWA-Ar quantifies the clinical manifestations of AWS, these are not specific to alcohol withdrawal. As such, other states of withdrawal and other medical conditions associated with an increase in catecholamines may mimic or coexist with AWS and cause a false-positive increase in the CIWA-Ar score (e.g., delirium, meningitis, drug ingestions, liver failure). Therefore, before initiating medical treatment for AWS, based on an elevated CIWA-Ar score, it is essential to assess the patient first to rule out other potential causes.
Importantly, one should not use the CIWA-Ar in a noncommunicative patient (e.g., one who is delirious or intubated). Regrettably, there is no standard assessment tool for monitoring such patients; however, in these cases it is reasonable to use a validated ICU sedation agitation scale to quantify the severity of agitation (e.g., the Richmond Agitation-Sedation Scale [RASS] [see Table 5.2, Chapter 5]). Similar to the CIWA-Ar, an increased RASS score is not specific for alcohol withdrawal; however, it is useful to guide therapeutic management. For example, clinicians can target treatment with benzodiazepines to a RASS goal of −2 to +1 to have objective drug administration goals.
Indications for Transfer to the ICU
Once one diagnoses AWS (Box 31.1), one must consider whether the patient has indications for ICU level of care (see Box 31.2). Patients who don’t meet the criteria in Box 31.2 for admission to the ICU should be able to be managed on a general medical floor—provided that the floor unit’s nursing staff has been trained to perform CIWA-Ar scoring in conjunction with a protocolized or physician-driven titration of appropriately dosed benzodiazepines.