Alcohol poisoning

  • Ethanol rarely causes life-threatening poisoning in adults, but this is possible with large doses.
  • For children, even small amounts of ethanol may be dangerous.
  • Isopropanol (and its metabolite acetone) causes a similar but more severe and long-lasting poisoning than ethanol.
  • Even small ingested amounts of the toxic alcohols methanol and various glycols (one swig, a few millilitres) may cause poisoning that is life-threatening for both adults and children if not treated.
    • Anyone who has ingested toxic alcohol must be sent immediately to emergency specialized care.
  • The treatment of ethanol or isopropanol poisoning depends on the severity of poisoning; see Table T1.
  • In the case of minors (< 18 years), a child welfare notification should be submitted.
  • For adults, any substance abuse should be reviewed (see (Providing care for an alcohol or drug abuser)) before discharge, and the need for involving services for substance abusers should be assessed.
  • Mixed intoxication is always possible.
    • Ethanol together with other toxic alcohols (such as solvents, windscreen cleaner solutions, antifreeze solutions, impure alcohol)
    • Medication together with other intoxicants

Ethanol

  • Ethanol rarely causes life-threatening poisoning, but this is possible with large doses. For children, even small amounts of ethanol may be dangerous.

Diagnosis

  • Various degrees of impaired consciousness
    • Heavy ethanol consumption for long periods increases the tolerance, and consciousness may be only slightly affected even if blood ethanol concentrations are very high.
  • Ataxia and incoordination, slurred speech
  • Nausea and vomiting
  • Respiratory depression (should particularly raise the suspicion of involvement of other drugs)
  • Often smallish or middle-sized pupils that react symmetrically but slowly
  • There may be hypoglycaemia and ketoacidosis. Children may develop hypoglycaemia at quite low doses.
  • Electrolyte disturbances (hyponatraemia, hypokalaemia, hypomagnesaemia) are common in association with long-term alcohol consumption.
  • If the patient has neurological abnormalities, fever, stiffness or convulsions or signs of external injury particularly in the head area, the following, in particular, must be considered in the differential diagnosis:
    • brain trauma
    • cerebral haemorrhage, subarachnoid haemorrhage
    • stroke
    • CNS infection
    • septic infection.

Treatment

  • The place of treatment should be chosen based on the patient’s condition and the facilities for monitoring and treatment.
  • In the case of mild or moderately severe ethanol poisoning, follow-up and fluid administration are enough; see Table T1.
  • If alcohol consumption has continued for several days or longer, the possibility of delirium should be kept in mind (see (Treatment of alcohol withdrawal)).
    • Thiamine (250 mg i.v. or i.m. once daily for 3 days) should be started to prevent Wernicke’s encephalopathy.
  • Any electrolyte or fluid imbalance (incl. abnormal blood glucose levels) should be treated.
  • Haemodialysis removes ethanol effectively but is only necessary in the case of severe, life-threatening poisoning (in children, for instance).
  • Any substance abuse should be reviewed in more detail before discharge, and the need for involving services for substance abusers should be assessed together with emergency social services, as necessary (see (Providing care for an alcohol or drug abuser)).
    • Child welfare notifications should be submitted for minors.
    • Social services can be notified of any adults (particularly elderly ones) if their coping raises concern.

Table 1. Severity of ethanol poisoning, blood ethanol levels, patient’s functional capacity and principles of treatment. The risk of delirium, as well as any disturbed fluid or electrolyte balance should always be considered in the treatment.
Severity of poisoning Blood ethanol level Performance capacity Treatment
Mild Usually less than 2 per mil Capable of functioning No need
Moderately severe 2–3 per mil Clearly affected, cannot stand on his/her feet, keeps dozing off Monitoring
Severe Usually > 3 per mil Unconscious, cannot be awakened Find out about abuse of any other illegal or legal drugs and any diseases or injuries that may cause impaired consciousness.
If consciousness is severely impaired, the following should be provided in specialized care:
  • intubation and mechanical ventilation
  • circulatory support

Isopropanol

  • Isopropanol (and its metabolite acetone) cause similar poisoning to ethanol but the intoxicating effect is stronger and lasts clearly longer.
    • The patient should be treated and examined as for ethanol poisoning.

Methanol, ethylene glycol or diethylene glycol poisoning

  • These alcohols are relatively harmless as such but produce toxic metabolites in the body.
    • Serious symptoms only occur after the production of such metabolites, with a delay that can be as long as 48–72 h.
  • Methanol is metabolized in the body to formaldehyde and formic acid, which have effects such as eye injuries (visual disturbances, even blindness) and metabolic acidosis.
  • Ethylene glycol (EG) forms calcium oxalate crystals with calcium. Together with the metabolites of ethylene glycol, these cause renal damage, hypocalcaemia and metabolic acidosis, for instance.
  • The effects of diethylene glycol (DEG) include renal damage and sometimes severe, permanent neurological symptoms.
  • The exact toxic doses are not known, and there is wide individual variation; even just one swig or a few millilitres may cause severe poisoning (see Table T2).
  • If ingestion of methanol or other surrogate alcohol is suspected, the patient should be immediately transferred to specialized care.

Table 2. Methanol, ethylene glycol or diethylene glycol poisoning
Alcohol Examples of mixtures where these can be found Toxic dose
Methanol Windscreen washer fluid, carburettor cleaner, some paints, paint remover, varnish, lacquer and detergents, antifreeze agents
Ordinary alcoholic drinks (bootleg liquor, drink spiking)
0.4–1.2 mg/kg or 30–200 ml may be lethal.
As little as 10 ml may cause blindness.
May also be toxic on inhalation or skin exposure.
Ethylene glycol Antifreeze solutions, car radiator fluids, de-icers, brake fluids, ink-jet printer colours, for instance
Its sweetness increases the risk of poisoning.
30 ml has been found to be lethal for adults, 1 ml/kg for children.As little as 10 ml may cause severe poisoning.
Low serum ethylene glycol levels do not exclude poisoning, and glycols cannot be detected by a breathalyser
False blood lactate elevation in cassette-based analysis
Diethylene glycol Car radiator fluids, brake fluids, solvents, inks, medicinal and cosmetic products Doses as low as 0.22 ml/kg have proved lethal.
As little as one swig may cause severe poisoning.

Symptoms

  • Symptoms may not occur until after 12–48 or even 72 h. Simultaneous ingestion of ethanol will slow down the appearance of symptoms.
  • During the first few hours, there will be inebriation similar to that caused by ethanol with irritation of the gastric mucosa.
  • Severe metabolic acidosis, hyperventilation and, depending on the substance, symptoms such as visual disturbances, kidney failure, decreased level of consciousness and convulsions will develop within 6–30 h. Hypocalcaemia and dehydration may occur.
  • Blood gas analysis should also be performed in primary health care, as far as possible, but this must not delay hospital treatment.

Treatment

  • Disturbances of bodily functions that are immediately life-threatening should be treated according to the general principles (respiratory and circulatory support, beginning rehydration).
  • If less than 2 h have elapsed since ingestion, gastric aspiration may be useful (nasogastric tube); induced emesis is not recommended.
  • Medicinal charcoal binds alcohol poorly but may be indicated in case of mixed intoxication.

Antidotes and further treatment

  • In primary health care only after consulting an emergency physician or other regionally agreed specialist
    • Sodium bicarbonate can be used for first aid in the case of acidosis.
    • If access to treatment is significantly delayed and specialized care is only available very far away, ethanol treatment during transportation may be considered.
  • For severe poisoning, adults should be given ethanol as an antidote p.o. or by infusion through a central venous catheter, and children and pregnant women should be given fomepizole. These compete with toxic alcohols for alcohol dehydrogenase, preventing the formation of toxic metabolites.
  • Calcium folinate (leucovorin) accelerates formic acid metabolism and may reduce visual disturbances associated with methanol poisoning.
  • Haemodialysis eliminates alcohols and their metabolites effectively. It should be started if the patient’s condition is getting worse despite other treatment; e.g. unconsciousness, convulsions, significant acidosis, visual symptoms (methanol), kidney failure (EG, DEG).


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