Toxicology – Alcohol Withdrawal

Definition

Alcohol withdrawal is a hyperadrenergic syndrome that develops after abrupt reduction or cessation of alcohol in someone with chronic heavy use. Symptoms can begin within several hours and may progress over the next few days.

Typical Presentation

Early withdrawal commonly causes:

• Anxiety
• Tremor
• Sweating
• Tachycardia
• Hypertension
• Agitation

Some patients may develop symptoms overnight and notice tremor or autonomic symptoms on waking.

Neurologic Features

As withdrawal progresses, patients may develop:

• Hallucinations – visual, auditory, or tactile
• Seizures
• Delirium tremens (DTs)

Alcohol-withdrawal hallucinations can occur while cognition is still relatively preserved.

Delirium Tremens

DTs represent severe withdrawal and are characterized by:

• Marked autonomic hyperactivity
• Confusion or delirium
• Agitation
• Hallucinations
• Severe tremor
• Tachycardia and hypertension

This is a medical emergency and requires close monitoring.

Mechanism of Action

Chronic alcohol exposure increases inhibitory GABAergic tone and suppresses excitatory NMDA/glutamate signaling.

Over time, the brain compensates by:

• Downregulating GABA activity
• Upregulating NMDA activity

When alcohol is suddenly removed, the balance shifts toward excessive CNS excitation, producing autonomic overactivity, hallucinations, and seizures.

Management

Treatment is aimed at controlling CNS hyperactivity and preventing complications.

Main therapies include:

• Benzodiazepines as first-line treatment
• Fluids and correction of electrolyte abnormalities when needed
• Thiamine supplementation in patients at risk of deficiency
• Close monitoring for seizures or delirium

Severe or refractory withdrawal may require:

• Phenobarbital
• ICU-level care
• Airway support if needed
• Additional sedative agents under specialist supervision

Key Points

• Alcohol withdrawal reflects excessive CNS excitation after removal of chronic alcohol exposure.
• Early symptoms are mainly autonomic: tremor, sweating, tachycardia, and hypertension.
• Hallucinations can occur before delirium.
• Seizures and DTs indicate more severe withdrawal.
• Benzodiazepines are the mainstay of treatment.