Prehospital Care
The prehospital care provider has several important tasks. First, the prehospital provider should search for any empty containers near the patient. In addition, a blood sugar level should be obtained on anyone who appears intoxicated. Local protocols and the skill level of the provider dictate additional prehospital care for patients with altered mental status.
Emergency Department Care
As with all emergency patients, initial treatment should focus on the airway, breathing, and circulation. Gastric decontamination is rarely necessary for any of the alcohols. An exception to this may be a patient who presents immediately after ingestion of a toxic alcohol in whom one might reasonably expect to be able to recover a significant amount of the toxin via aspiration through a nasogastric tube.
Treatment of ethanol and isopropanol intoxication is largely supportive. [24] Because of the hemorrhagic gastritis that can follow isopropanol ingestion, H2 blockade or proton-pump inhibitors may be helpful. Hemodialysis, while effective, is rarely indicated, and should only be used in the setting of profound hemodynamic compromise. [5]
Once either methanol or ethylene glycol intoxication are suspected, treatment should be initiated without delay. Fortunately, since both alcohols are metabolized by alcohol dehydrogenase, the treatment is the same, and differentiating which of the two toxic alcohols is responsible is not necessary before implementing treatment. [24]
The primary antidotal treatment of methanol or ethylene glycol involves blocking alcohol dehydrogenase. This enzyme can be inhibited by either ethanol or fomepizole. [25, 26, 27] Toxic alcohol levels are frequently not immediately available. Thus, ideally, if methanol or ethylene glycol poisoning is suspected, the patient should receive a loading dose of fomepizole while the levels are being obtained. Because the next dose of fomepizole is not due for an additional 12 hours, this strategy allows 12 hours for the blood to be processed at a reference laboratory before additional treatment is needed.
Inhibition of alcohol dehydrogenase with ethanol may be substituted for treatment with fomepizole (see below), though studies have highlighted the greater safety of fomepizole as a treatment, when available. [11] In some patients, treatment with fomepizole alone may represent definitive treatment and can prevent the need for hemodialysis. [28]
In addition to blocking alcohol dehydrogenase, significant metabolic acidosis should be treated with sodium bicarbonate infusions. If methanol is suspected, folinic acid should be administered at a dose of 1 mg/kg, with a maximal dose of 50 mg. It should be repeated every 4 hours. If folinic acid is not immediately available, folic acid can be substituted at the same dose.
If ethylene glycol overdose is suspected, the patient should also receive 100 mg of intravenous thiamine every 6 hours and 50 mg of pyridoxine every 6 hours. The purpose of the thiamine and pyridoxine is to shunt metabolism of glyoxylic acid away from oxalate and favor the formation of less toxic metabolites.
In methanol overdose, sodium bicarbonate should be administered liberally, with the goal being to completely reverse the acidosis. Experimental studies suggest that formate is excreted in the kidneys at a much higher rate when the patient is not acidotic. In addition, when the patient is not acidotic, formic acid dissociates to formate at lower rates so that less formate crosses the blood-brain barrier. Thus, in methanol intoxication, correcting the acidosis actually speeds up elimination of the toxic compound and decreases toxicity.
If ethanol is used as an antidote, the recommended target serum concentration is 100-150 mg/dL. Because ethanol inhibits gluconeogenesis, hypoglycemia is common in patients on an ethanol infusion. [29] Hypoglycemia is particularly prevalent in pediatric patients on such drips. Thus, serum glucose levels must be checked frequently, at least every 2 hours. In addition, because it is difficult to attain a steady serum concentration of ethanol, the ethanol level also must be checked frequently, and titrations made.
A 5% or 10% ethanol solution can be made in the pharmacy. If giving ethanol, administer a loading dose of 600 mg/kg, followed by a drip of 66-154 mg/kg/h, with chronic alcoholics requiring doses at the higher end of the scale. Ethanol can be given either intravenously or orally.
In addition to hypoglycemia, additional adverse effects from ethanol infusion include inebriation, CNS depression, pancreatitis, and local phlebitis. Because of the phlebitis that occurs with ethanol infusions, some advocate that ethanol should only be administered via a central venous line.
Ethanol infusions are not only labor intensive, but once the costs of the frequent blood glucose and serum ethanol level assays are accounted for, ethanol antidotal therapy is frequently more expensive than fomepizole. Ethanol has also been associated with more frequent adverse reactions than fomepizole. [30] Thus, because of the lower overall cost and the ease of administration and safety considerations, fomepizole has become the preferred antidote for methanol or ethylene glycol poisoning. [31]
Fomepizole should be administered as a loading dose of 15 mg/kg. Subsequent doses should be at 10 mg/kg every 12 hours for 4 doses. Because fomepizole actually induces its own metabolism after 48 hours of treatment, if additional doses are needed, the dose should be increased to 15 mg/kg. Fomepizole needs to be re-dosed during hemodialysis. The package insert or local poison center can help with the re-dosing strategy. Fomepizole should be continued until the serum ethylene glycol or methanol concentrations are less than 20 mg/dL.
Hemodialysis is frequently required in patients with significant methanol or ethylene glycol ingestions. [24, 28] Indications for hemodialysis include the following:
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Arterial pH < 7.10
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A decline of >0.05 in the arterial pH despite bicarbonate infusion
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pH < 7.3 despite bicarbonate therapy
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Rise in serum creatinine level by 90 mmol/L
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Initial plasma methanol or ethylene glycol concentration ≥50 mg/dL
A number of case reports suggest that hemodialysis should be considered in the treatment of severe alcohol intoxication with serum ethanol levels > 450 mg/dL. Close monitoring is required when administering hemodialysis to patients with alcohol use disorder as alcohol withdrawal syndrome could be triggered by the rapid elimination of ethanol. [32]
Patients with ethanol intoxication can usually be observed until they are no longer clinically intoxicated and then discharged. Patients with isopropanol ingestion may require observation in the hospital. Patients with significant ingestions of toxic alcohols require hospital admission in a closely monitored setting such as the intensive care unit. Patients who are alcoholics may be at risk of alcohol withdrawal if admitted to the hospital. Patients with known or suspected methanol or ethylene glycol intoxication should be monitored closely, probably in an intensive care unit.
Consultations
For patients with ethanol intoxication who appear to have issues with dependence or abuse, consider referral to an alcohol detoxification facility. Consult a toxicologist for all known or suspected cases of isopropanol, methanol, or ethylene glycol ingestion. If a toxicologist is not immediately available at the medical center where the patient is located, the regional poison control center can be contacted at (800) 222-1222.
Consult a nephrologist for any known or suspected cases of methanol or ethylene glycol intoxication to assist in the decision making for hemodialysis.
Complications
Ethanol ingestion complications include the following:
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Hypoglycemia is common. [29] The etiology is multifactorial but largely related to decreased glycogen stores and malnutrition in children and chronic alcoholics, as well as ethanol’s inhibition of glycogenolysis.
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Patients with acute intoxication may exhibit "holiday heart," in which dysrhythmias, especially atrial fibrillation, occur following a heavy drinking episode. Ethanol lowers the threshold for developing atrial fibrillation.
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Cirrhosis, esophageal varices, and erosive gastritis are common in patients who use ethanol on a frequent basis.
Complications of other alcohols include the following:
