Alcohols: Ethyl alcohol (Ethanol), Methanol, Isopropanol, and Ethylene Glycol, Their Complications
Ethyl alcohol (Ethanol)
- Alcohol levels can be estimated in blood, breath, and saliva.
- When collecting blood, then don’t clean the site with alcohol. Clean the site with an alcohol-free disinfectant like benzalkonium chloride.
- A blood test is the best sample for the estimation of alcohol.
- Blood samples in a living patient may be whole blood, serum, or plasma.
- The serum and blood alcohol ratio are 1:14.
- Blood in a cadaver is taken from the aorta.
- The blood must be capped to avoid the evaporation of alcohol.
- Collect blood in sodium fluoride or potassium oxalate.
Precautions for Ethyl alcohol (Ethanol)
- Use alcohol-free disinfectants. Take a blood sample without the use of any alcohol skin cleaning solution.
- Alcohol is volatile, so capped the bottle to avoid evaporation.
- Can store the blood when it is properly sealed for 14 days at room temperature or at 4 °C with or without preservatives.
- For longer storage or nonsterile postmortem material, specimens use preservative sodium fluoride.
Measurement can be done on the following samples:
- Blood alcohol levels were tested in serum or plasma or whole blood.
- An arterial blood sample is higher than a venous sample.
- Capillary blood from the finger prick or ear lobules is about 70% to 85% of the arterial blood.
- The serum value is 18% to 20% higher than the whole blood level.
- Blood levels correlated by the law are whole blood samples.
- Serum: whole blood ratio is 1.03 to 1.35.
- Rainey, in 1995, gave a median serum/whole blood conversion ratio of 1.15 rather than 1.20.
- Breath test:
- The police mostly use breath tests; these are easy and can be done anywhere.
- A breath analyzer measures the concentration of ethanol at the end of deep expiration after the deep inspiration.
- Alcohol level: breath/blood alcohol ratio is 2100:1. Multiply the value by 2100.
- Breath alcohol = g/210 L
- The above value is equal to blood alcohol g/dL.
- Before performing the breath test wait for 15 minutes to rule out:
- Alcohol may be present in the mouth in case of recent drinking.
- Vomiting containing alcohol-rich gastric fluid.
- Alcohol-containing mouth wash.
- There should be no smoking.
- Some of the mouthwashes produce a significant level 2 minutes after use, but it is no more after 10 minutes.
- Ketone bodies may interfere in the breath test.
- In case of a breath negative test, indicate some other medical emergencies.
- Saliva may be used where alcohol concentration is 9% higher than that in the whole blood.
- This is an easy and noninvasive method.
- The urine alcohol sample is noninvasive and easy to collect the sample.
- During the post-absorptive stage after alcohol intake, the concentration of the alcohol in the urine is roughly 1.3 times that in the blood.
- This is variable, so it is better to empty the bladder and then collect urine after 20 to 30 minutes.
- It can detect the ingestion of alcohol within the previous 8 hours.
- Urine samples are not recommended because of the variable blood/urine ratio and the stasis of the urine in the urinary bladder.
- But urine can be used for screening purposes.
Indications for Ethyl alcohol (Ethanol)
- Quantitation of the alcohol level is done for therapeutic or legal purposes.
- The alcohol level is done to diagnose alcohol intoxication.
- Alcohol levels may be done in cases of coma, cerebral trauma, and drug overdose.
- To differentiate an alcoholic intoxication coma from a diabetic coma.
- This test is also done for alcoholism.
- This test is done on the drivers.
Pathophysiology of Ethyl alcohol (Ethanol)
Definition of an alcoholic person:
- Alcohol shows a range of actions on the central nervous system extending from sedation to anesthesia, and intake of alcohol leads to impairment of judgment and thinking and altered behavior.
- The legal definition of alcohol intake is when a person has a blood level of alcohol of 0.1 g/dl or 100 mg/dL.
- Alcohol is Ethanol, and it is readily absorbed from the GI tract.
- The peak level is within 40 to 70 minutes after the intake.
- The liver enzyme dehydrogenase metabolizes ethanol into acetaldehyde.
- 90% of alcohol is metabolized in the liver.
- This acetaldehyde is converted into acetic acid by the enzyme Aldehyde Dehydrogenase.
- For the diagnosis of alcoholism:
- A major criterion is a blood alcohol level >15 mg/dL at any time.
- The minor criterion is blood alcohol concentration is >300 mg/dL at any time, and blood alcohol concentration is 100 mg/dL.
- Toxic concentration blood alcohol level is ≥200 mg/dL.
- The lower limit to detect blood alcohol level is 100 µg/mL.
Alcohol (Ethyl alcohol) metabolism:
- Ethanol easily diffuses into the body fluids and is partially cleared in the urine and other body excretion.
- Its major metabolic pathway is its conversion into acetaldehyde by the alcohol dehydrogenase enzyme in the liver.
- Acetaldehyde is converted into acetate by the acetaldehyde dehydrogenase enzyme.
- Ethanol metabolite acetaldehyde leads to acidosis and ketosis called Alcoholic ketoacidosis.
- Ethanol is converted to acetaldehyde.
- Headache, flushing, and hangover are due to acetaldehyde before it is metabolized to acetate.
- Ethanol is converted to acetaldehyde.
- Once the peak level is reached, then its level decreases.
Effect of Ethyl alcohol (Ethanol) on the body:
- Ethanol depresses the CNS and ultimately may lead to coma and death.
- ≤50 mg/dL = Euphoria and decreased inhibitions.
- 100 to 300 mg/dL = Incoordination and decreased orientation.
- >400 mg/dL = Coma and death.
- CNS dysfunction is more pronounced when:
- Absorptive phase: Ethanol concentration in the blood is increasing.
- Elimination phase: When the level of alcohol is declining.
- Alcohol causes diuresis by inhibiting the secretion of the ADH (antidiuretic hormone) by the posterior pituitary.
- It also inhibits the secretion of oxytocin. Because this property is used to stop uterine contractions in premature labor.
- Alcohol blood concentration level of 100 mg/dL has been established to limit car/truck driving in most states in the United States.
- While in 17 states, this limit is 80 mg/dL.
- When ethanol is used with other CNS-depressant drugs, then ethanol exerts potentiation or synergistic depressant effect.
- Alcohol is present in the blood, urine, stomach contents, and breath.
- Saliva’s alcohol level is 9% higher than blood.
- The blood-alcohol level of 50 to 100 mg/dL causes:
- Slowing of reflexes.
- Impaired vision.
- The blood-alcohol level of >100 mg/dL causes:
- Signs of CNS depression seen.
Toxic Effect of blood alcohol:
- A blood alcohol level >300 mg/dl is usually associated with a coma.
- A blood-alcohol level of >400 mg/dL is fatal, and death may occur.
- The pregnant ladies taking alcohol will have low-birth-weight babies.
- Alcoholic mother babies will have mental retardation and fetal alcohol syndrome (an irreversible congenital disorder).
- Nutritional and metabolic studies have demonstrated that alcohol can cause hypertension.
Level of the alcohol intake:
- The blood-alcohol level will increase roughly 15 to 25 mg/dL when adult taking:
- An ounce of whiskey or.
- 12 ounce of the bear or.
- One glass of wine.
- Women absorb more quickly than men and show a 35% to 45% higher blood alcohol level. During the menstrual cycle, the peak occurs more rapidly. Birth control pills cause higher levels and sustain it.
- The use of sedatives like barbiturates and benzodiazepines with alcohol is hazardous and may lead to death by respiratory depression.
The complication of alcohol in chronic drinkers:
- Chronic use of alcohol may lead to:
- Cirrhosis of the liver.
- The degenerative changes in the brain.
- The degenerative changes in the skeletal muscles.
- Chronic alcoholics may have nutritional and vitamin deficiencies.
The rate of elimination of ethanol from the blood circulation:
- Men = 11 to 22 mg/dL/ hour.
- Average level is = 15 mg/dL/hour.
- Women = 11 to 22 mg/dL/hour.
- Average level is = 18 mg/dL/hour.
- Drinking habits also influence the elimination rate.
- For example = Alcoholics have an average elimination rate of about 30 mg/dL/hour.
Alcohol or ethanol intake effects on the body (Complications of alcohol):
- Ethanol ingestion leads to hypoglycemia and ketonemia because of the inhibition of gluconeogenesis.
- Lactate accumulates and competes with uric acid for excretion through the kidney. So serum uric acid level is increased.
- When alcohol is taken with fatty meals, it leads to hypertriglyceridemia, which may persist for more than 12 hours.
- The moderate intake of alcohol for one week leads to increased serum triglyceride >20 mg/dL.
- The toxic level of alcohol stimulates the release of:
- Increased intake of alcohol leads to:
- The decreased plasma testosterone level in the men.
- There is an abnormal pituitary, adrenocortical, and medullary function.
- Alcohol ingestion after metabolized leads to acetaldehyde formation, which causes damage to mitochondria of hepatocytes, and H+ leads to fat accumulation.
- In chronic alcoholism, there is an increased level of acetaldehyde and acetate.
- The acetate enters the acetyl-CoA cycle and leads to increased synthesis of fatty acids, and the result is fatty liver.
- Ethanol leads to diuresis by inhibiting the ADH from the posterior pituitary.
- It also inhibits the secretion of Oxytocin from the posterior pituitary. So can be used in stopping uterine contraction in premature labor.