What is Methanol Poisoning?

The toxic effect of methanol on the human body is caused by methanol and its metabolites, formaldehyde and formic acid. It is mainly characterized by central nervous system damage, eye damage, and metabolic acidosis. Methanol itself has an anesthetic effect and has a direct toxic effect on nerve cells. Formic acid damages the optic nipples and optic nerves, causing optic papillary edema, optic nerve myelin damage, and optic nerve damage. Accumulation, production of formic acid, a methanol metabolite, leads to metabolic acidosis.

Basic Information

English name

methylalcoholpoisoning

Visiting department

Emergency Department

Common causes

Oral poisoning, occupational poisoning

Contagious

no

Causes of methanol poisoning

Oral poisoning

Mostly caused by alcohol or beverages deliberately taking methanol, accidentally taking methanol, or industrial alcohol containing methanol. The lowest dose of oral poisoning in humans is about 100 mg / kg of body weight, and oral intake of 0.3 to 1 g / kg can be fatal.

2. Occupational poisoning

Mainly found in the production and transportation of methanol and the industry using methanol as a raw material or solvent. Such as poor ventilation or accidents, inhalation of high concentrations of methanol in a short period of time can cause acute or subacute poisoning; if a large amount of methanol is absorbed through the skin, it can also cause poisoning.

Clinical manifestations of methanol poisoning

Acute poisoning

It is caused by ingestion of methanol or industrial alcohol blended with alcohol or beverage, or inhalation of a large amount of methanol vapor. The clinical manifestations are central nervous system symptoms, eye damage, and metabolic acidosis, which can be complicated by acute pancreatitis and arrhythmia. , Transaminase elevation and renal dysfunction.

The incubation period is 8 to 36 hours. If you take ethanol at the same time, you can extend the incubation period. The early stage of poisoning was drunk, with symptoms of dizziness, headache, fatigue, drowsiness, or insomnia, and rarely the euphoria of alcohol poisoning; severe cases of delirium, blurred consciousness, and coma. Both eyes may have pain, blurred vision or diplopia, sudden loss of vision, or even blindness; fundus examination showed retinal congestion, bleeding, and optic nerve papillary edema.

2. Chronic poisoning

Can be manifested as vision loss, visual field defects, optic nerve atrophy, with autonomic dysfunction and other symptoms.

Methanol poisoning test

1. Increased white blood cell count; some liver and kidney functions are abnormal.

2. Blood gas analysis

Metabolic acidosis (decreased pH, decreased SB, and increased negative BE), reduced CO2 binding.

3. ECG

Visible arrhythmias such as ST-T changes and ventricular premature beats.

4. Visual evoked potential (VEP) examination

It is helpful for the diagnosis of early optic nerve damage.

5.Cranial brain CT examination

Severe poisoning can be seen in reduced white matter and basal ganglia density and lenticular lesions.

6. Methanol and formic acid increase in blood and urine.

Diagnosis of methanol poisoning

1. Have a history of taking alcohol or alcohol mixed with methanol or industrial alcohol containing methanol, or inhaling a large amount of methanol vapor;

2. Clinical manifestations of central nervous system symptoms, eye damage, and metabolic acidosis;

3. Increased concentrations of methanol and formic acid in blood and urine.

Methanol poisoning treatment

1. leave the scene

Oral poisoning induces vomiting and gastric lavage. Skin contaminated skin cleansing.

2. Intravenous drip

Intravenous infusion of 2% to 5% sodium bicarbonate corrects metabolic acidosis. The degree of metabolic acidosis determines the severity and prognosis of methanol poisoning.

3. Severe poisoning

Feasible hemodialysis.

4. Fundus Lesions

Try intravenous drip of mannitol and dexamethasone.

5. Detoxification treatment

Folic acid promotes the oxidation of formic acid to carbon dioxide and water. 4-methylpyrazole inhibits alcohol dehydrogenase and prevents the metabolism of methanol to formic acid.

6. Symptomatic supportive care

Intravenous fluid replacement maintains heat, water, and electrolyte balance. Gauze or goggles cover your eyes and avoid light irritation.

Methanol poisoning prevention

Strictly abide by the operating regulations; strengthen storage to prevent accidental use or use of methanol for alcoholic beverages; regular health and safety monitoring