Methanol poisoning is intoxication with methyl alcohol (methanol), the metabolites of which have a harmful effect on the human organism. Depending on body weight and general condition, even less than 30 ml can be lethal.
What is methanol poisoning?
Methanol poisoning is defined as excessive exposure of the human organism to methyl alcohol, which has a toxic effect (methanol intoxication). Generally, a distinction is made between acute and chronic methanol intoxication. Acute intoxication with methanol is characterized by a single ingestion of a high quantity of methanol. If the alcohol is absorbed into the gastrointestinal tract after about 12 to 24 hours, nausea, vomiting, headache, visual dizziness and dizziness manifest themselves. In more pronounced cases, convulsive twitching and impaired consciousness may be observed. Due to the paralyzing effect on the circulatory and respiratory centers, acute methanol poisoning can lead to death. In chronic methanol poisoning, on the other hand, small amounts of methanol are inhaled or absorbed through the skin, leading to visual disturbances and damage to the visual and auditory nerves when exposed over a long period of time. Loss of appetite, abdominal pain, recurrent irritation of the ocular and respiratory mucous membranes are other characteristic symptoms of chronic methanol poisoning.
Causes
In methanol poisoning, after ingestion (absorption), methanol is converted in the liver by the enzymes alcohol dehydrogenase and aldehyde dehydrogenase to its harmful metabolites (metabolites) formic acid and formaldehyde. The metabolites are only slowly eliminated or excreted renally (via the kidneys), so that these two toxic substances accumulate in the body. While formic acid causes metabolic acidosis with metabolic derailment, formaldehyde has a direct damaging effect on the adjacent organs. Poisoning with methanol is caused primarily by the consumption of low-quality or improperly home-distilled spirits, which may contain higher amounts of methanol. In addition, methanol is used commercially as a solvent for varnishes, adhesives, and paints, as well as in the pharmaceutical, chemical, and cosmetic industries, which can cause chronic methanol poisoning if inhaled continuously or absorbed through the skin.
Symptoms, complaints, and signs
Methanol poisoning is manifested by visual disturbances, nausea and vomiting, severe headache, and dizziness. As a result of the acidosis, impaired consciousness may also develop. The highly acidified urine has an unusual odor and often also takes on a strong yellow color. Furthermore, methanol poisoning can impair hearing. Those affected are then no longer able to perceive low tones correctly, and later high tones are also no longer perceived. Often the liver is also involved and signs of jaundice appear, i.e. yellow skin, pallor and a strong feeling of malaise. Externally, symptoms such as acidosis are noticeable by a blue coloration of the lips and pale skin. Strong bad breath and accelerated breathing are also typical. In the long term, methanol poisoning causes vision problems, hearing problems, atherosclerosis, arthritis, osteoporosis, cardiac insufficiency and diseases of the immune system. The chronic form of the disease develops over months or years of repeated consumption of low-quality spirits or other products containing methanol. Acute methanol poisoning occurs within a few hours of alcohol consumption and paralyzes the cardiovascular and respiratory systems. The acute form can lead to patient death if left untreated.
Diagnosis and course
Methanol poisoning can be diagnosed in many cases on the basis of clinical symptoms and information obtained from the patient’s medical history regarding possible exposure to methanol (working with solvents, consumption of low-grade spirits). In addition, in acute methanol poisoning, an enlarged liver, oliguria or anuria, in pronounced cases uremia with residual nitrogen, and an increase in blood pressure can be detected. In addition, the urine is in the acidic range as well as a very strongly increased concentration of calcium oxalate crystals with very strongly lowered erythrocyte and leukocyte counts.Metabolic acidosis can be diagnosed in the course of a blood gas analysis (including lowered carbon dioxide partial pressure). In chronic methanol poisoning, methanol can be detected in the urine and blood. In addition, an elevated formic acid concentration can usually be detected in the urine. The course and prognosis of methanol poisoning correlate with the time of diagnosis and the start of therapy. The later intoxication with methanol is recognized, the more likely irreversible impairments are. If left untreated, methanol poisoning is usually lethal. Furthermore, late effects, especially loss of visual acuity, can be observed in methanol poisoning.
Complications
In general, methanol poisoning has a very negative effect on the health of the patient, and in the process, in the worst case, can even lead to the death of the affected person. However, this case only occurs when larger amounts of methanol have been introduced into the body. However, even small amounts can cause severe damage, especially to the internal organs and the brain. The damage is usually irreversible. As a result of methanol poisoning, those affected suffer from severe visual disturbances and, in many cases, veil vision. Furthermore, there is vomiting and severe nausea. Patients also complain of dizziness and headaches and also suffer from impaired consciousness. The person’s thinking and actions are also significantly impaired by methanol poisoning. As a rule, methanol poisoning must be treated acutely by an emergency physician or in a hospital. Consequential damage can be avoided with gastric lavage. Complications usually only occur at higher levels, and damage to internal organs can occur. However, the exact course of the disease depends very much on the amount of methanol ingested.
When should you see a doctor?
People who suffer from sudden symptoms such as vomiting, nausea, dizziness, or headache should see a doctor. If there is impairment of the usual vision or if the general risk of accidents increases, a medical examination is needed. If the complaints increase in scope or intensity, a doctor must be consulted. Disturbances of consciousness are signs of an existing irregularity that must be examined and treated. If a loss of consciousness develops, emergency medical services should be alerted. First aid measures must be taken until the emergency medical technician arrives to prevent the premature demise of the affected person. A pale or yellowish complexion, cold limbs or discoloration of the lips are further indications of a health problem. Blue discoloration of the lips is a characteristic feature of methanol poisoning and should be treated as soon as possible. If there is a loss of hearing, there is cause for concern. If low-pitched sounds in particular can no longer be heard by the affected person, a visit to the doctor is advisable. If there is a general feeling of malaise or unusual bad breath, the symptoms should be clarified by a doctor. If the affected person suffers from a weakened immune system, a decrease in internal strength or sleep disturbances, a doctor is needed. If irregularities of the heart rhythm set in, further medical tests should be performed immediately to determine the cause.
Treatment and therapy
Because methanol is metabolized only slowly, gastric lavage is usually performed first in cases of methanol poisoning. Another therapeutic measure is to inhibit methanol oxidation with orally administered or infused ethanol or fomepizole. Both substances have a much higher affinity for aldehyde dehydrogenase and alcohol dehydrogenase, so that the metabolization of methanol in the liver can be effectively prevented until renal elimination. In addition, alkalizing substances such as sodium bicarbonate and trometamol are administered in parallel to compensate for metabolic acidosis (pH in arterial blood is acidic or below 7.35). As a result of the normalized extracellular and intracellular pH, the degradation of formic acid is accelerated (increased degree of dissociation), which may reduce the toxic effect. In addition, the damaging effect of formic acid can be accelerated by high doses of folic acid, which promotes the oxidation of the substance to carbon dioxide.In severe cases of methanol poisoning (over 100 ml ingestion) or in the presence of renal insufficiency, hemodialysis (renal replacement procedure) is required for rapid elimination of methanol and its metabolites. In the case of chronic methanol poisoning, exposure cessation (avoidance of all methanol sources) and dietary changes (vitamin– and protein-rich diet, increased fluid intake) are generally recommended. In addition, organ damage caused by methanol poisoning should be treated.
Outlook and prognosis
In the case of methanol poisoning, the further development of health depends on the amount of high-proof alcohol consumed, the weight of the affected person, and his or her general condition. The higher the ingested level of methyl alcohol, the less favorable the further course. Under optimal conditions, the symptoms are relieved within a few hours. In most cases, freedom from symptoms is achieved within one to two days. The prerequisite for this is a good state of health of the person affected and a weight in the normal range of the BMI. In addition, a good and balanced lifestyle should always be present in order to achieve lasting relief of the symptoms. However, if a high amount of methyl alcohol is consumed, there is basically a danger to life. In addition, irreparable damage to the internal organs can occur and cause lifelong impairments. In the case of poor health and existing pre-existing conditions, the further course is usually unfavorable. If alcoholism is already present, consequential damage can hardly be ruled out. Normally, the lower the patient’s weight, the more severe the further complications and long-term health impairments. In acute cases, only an ambulance service and intensive medical care can save the life of the affected person. In these situations, damage to the brain is to be expected. These worsen the overall quality of life.
Prevention
Methanol poisoning can be prevented by avoiding high-proof spirits of unknown origin or inferior quality. In occupational activities involving exposure to methanol, the appropriate protective measures (including protective gloves, clothing, eye and face protection, well-ventilated rooms) should be taken to prevent methanol poisoning.
Aftercare
Because methanol poisoning is a serious type of poisoning, adequate aftercare is extremely important. To rebuild the intestinal flora that has been affected, patients can, for example, follow a course of treatment with lactic acid bacteria. It is generally recommended that the stomach be revitalized with gentle food for a while after the acute phase. Since the immune system is battered by the food poisoning, susceptibility to germs is increased. The focus should therefore be on cautious familiarization with food and medical observation by the attending physician. Affected individuals have a personal responsibility to stay away from menthanol-containing substances.
This is what you can do yourself
In the case of mild methanol poisoning, the affected person should drink sufficient amounts of non-carbonated and natural mineral water. The intake of water alleviates the percentage of methanol in the organism, as it mixes with the water. The total amount of fluids additionally causes it to be excreted more quickly. In some cases, this improves physical well-being. Rest should be maintained and overexertion should be avoided. In order to minimize the risk of injury, it is helpful if the affected person takes a sitting position and pays attention to the changes in the organism. If his condition gradually improves, there is a good chance that he will be symptom-free in some time. If the symptoms increase, a doctor should be called, as self-help options are exhausted. In case of severe poisoning, only medical treatment will help. There is a possibility that organs are damaged and permanent damage develops. The longer a consultation with a doctor is avoided, the more severe the symptoms will be. During an ongoing treatment, individual self-help options can be worked out in cooperation with the doctor. These focus on optimizing a healthy lifestyle.This includes a balanced diet rich in vitamins and sufficient exercise. Toxins such as alcohol or nicotine should be avoided.
