All alcohols are potentially toxic and cause clinical inebriation. Ethanol and isopropanol are the most commonly ingested alcohols and cause direct toxicity, while methanol and ethylene glycol cause toxicity as a result of conversion to toxic metabolites.
Ethanol is the most commonly abused drug in the world. While acute toxicity may result in death due to respiratory depression, the majority of morbidity and mortality is due to trauma owing to impaired cognitive function. Blood ethanol levels correlate poorly with the degree of intoxication due to the development of tolerance. On an average, nondrinkers metabolize ethanol at a rate of 20 mg/dL/h, whereas chronic alcoholics metabolize ethanol at a rate of 30 mg/dL/h.
Signs and symptoms of ethanol intoxication include disinhibited behavior, slurred speech, impaired coordination, followed later by respiratory and central nervous system (CNS) depression.
Diagnosis and Differential
Head injury and hypoglycemia can present similarly to ethanol intoxication, and these diagnoses may coexist. Glucose should be measured in all patients with altered mental status. In those patients without a clear explanation for their altered mental status, serum ethanol levels may help confirm intoxication, although the value may be difficult to interpret. For patients with comorbid disease or injury, additional labs that may be helpful include the following: electrolytes may demonstrate an anion gap acidosis; liver enzymes may reveal hepatic damage. Obtain imaging as indicated by external signs of trauma in the inebriated patient.
Emergency Department Care and Disposition
The mainstay of treatment is observation. A careful physical examination should be performed to evaluate for complicating injury or illness.
Treat hypoglycemia with IV dextrose. Thiamine 100 mg IV or IM may be given concurrently if Wernicke encephalopathy is suspected.
Consider secondary causes of deterioration or lack of improvement during observation and manage accordingly.
Discharge the patient once sober enough to pose no threat to self or others.
Isopropanol is commonly found in rubbing alcohol, solvents, skin and hair products, paint thinners, and antifreeze. Acetone is the principal toxic metabolite.
Clinically, isopropanol intoxication is similar to that of ethanol but produces a greater degree of intoxication than ethanol. Severe poisoning presents as coma, respiratory depression, and hypotension. Hemorrhagic gastritis is common and causes nausea, vomiting, abdominal pain, and upper gastrointestinal (GI) bleeding.
Diagnosis and Differential
A glucose level should be measured in all patients with altered mental status. Laboratory studies may reveal an elevated osmolal gap, ketonemia, and ketonuria, without acidosis. In the setting of upper GI bleeding, coagulation studies, a complete blood count, and a type and screen should be obtained. When available, serum isopropanol and acetone levels confirm the diagnosis, but are not required for management.