24. Substance Abuse

Question 1

Alcohol effects

Alcohol withdrawal

Answer 1

Alcohol increases effects of GABA on the GABAA receptor, thus increasing its inhibitory effects.

Alcohol inhibits the excitatory effects of glutamate at the N-methyl-D-aspartate (NMDA) receptor, thereby decreasing neuronal excitability.

During alcohol withdrawal, a state of hyperexcitability and autonomic dysfunction becomes apparent (hypermetabolic state)

Question 2

BZDs for alcohol withdrawal treatment and prevention

Answer 2

Scheduled dosing for patients with moderate or high risk.
- Doses high enough to relieve symptoms over the first 24-48 hours and the patient is slowly weaned (by ~20% per day) over the next 3-5 days.
- Longer acting BZDs such as diazepam (Valium) starting at 5-10mg PO/IV/IM Q6-8 hours or chlordiazepoxide (Librium) 25-100mg PO/IV/IM Q4-6 hours.

Question 3

DT precautions/prophylaxis orders

Answer 3

Thiamine 100mg IM/IV daily
Folate 1mg PO/IV daily
Multivitamins PO/IV
Magnesium sulfate 1g IM/IV daily
Benzodiazepines as needed or scheduled

Question 4

Differential diagnosis of AMS

Answer 4

• Toxic (drug overdose or toxicity)
• Metabolic (hypoglycemia, hepatic encephalopathy, uremia)
• Infectious (systemic or CNS)
• Inflammatory (demyelinating disease or CNS vasculitis)
• Vascular (large vessel infarction or intracranial hemorrhage)
• Traumatic (increased ICP 2/2 closed head injury)
• Hypoxemia/hypercarbia
• Psychotic episodes

Question 5

Work-up of AMS

Answer 5

Blood alcohol
Urine drug screen
Head CT

Question 6

Wernicke’s encephalopathy triad

Answer 6

• Encephalopathy
• Ophthalmoplegia
• Ataxia

Treated with thiamine 50-100mg IV QD (give before glucose because glucose further depletes thiamine and accelerates development of Wernicke’s encephalopathy).

Question 7

Korsakoff syndrome

Answer 7

Memory impairment without significant deficits of other cognitive functions.