Describe acute and chronic alcohol intoxication with the medicolegal examination for drunkenness.

Pharmacology and Blood Levels

• Absorption — about 20% from the stomach and 80% from the small intestine; peak blood level at 30 to 90 minutes, delayed by food, especially fat and protein
• Distribution — throughout body water; volume of distribution about 0.6 L/kg in men and 0.5 in women, which is why a woman reaches a higher level from the same drink
• Metabolism — over 90% in the liver by alcohol dehydrogenase to acetaldehyde, then by aldehyde dehydrogenase to acetate. The kinetics are zero order — a constant amount is removed per unit time, independent of the concentration — at about 15 to 20 mg/dL per hour, faster in a habituated drinker. This is what permits back-calculation of the level at an earlier time, with appropriate caution
• The widmark formula — A = c × p × r, where A is the amount of alcohol in the body, c the blood concentration, p the body weight, and r the distribution factor (0.6 for men, 0.5 for women)

The Medicolegal Examination for Drunkenness

• This is a medicolegal examination and consent is essential; a person cannot be examined by force, and refusal is recorded — though under the Motor Vehicles Act refusal to provide a breath sample is itself an offence
• What to examine — the general demeanour and cooperation; the smell of the breath, recorded but not relied upon; speech (slurred, thick, garrulous); gait and balance — the romberg test, walking a straight line, the finger-nose test and picking up small objects; pupils (dilated, sluggish) and nystagmus; the pulse, blood pressure and temperature; and the state of the clothing, soiling and vomit
• What must be excluded before attributing the state to alcohol — and this is the crux of the examination: head injury, particularly a subdural haematoma in a person who has fallen; hypoglycaemia; diabetic ketoacidosis, whose ketotic breath is mistaken for alcohol; stroke; hepatic encephalopathy; meningitis; epilepsy in the post-ictal state; and other drugs. Always check the blood glucose
• The sample — blood taken with sodium fluoride and potassium oxalate (fluoride prevents both bacterial fermentation and glycolysis), and the skin cleaned with a non-alcoholic antiseptic such as an aqueous antiseptic or soap and water — using spirit invalidates the result and is the classic procedural error. Urine and breath may also be taken
• The opinion — the correct form of words is whether the person is "under the influence of alcohol to such an extent as to be incapable OF taking care OF himself" or of performing the relevant duty. The doctor does not certify "drunk", which is a lay conclusion; the opinion is about capacity, and it must state whether any illness or injury could account for the findings

Chronic Alcoholism, Methanol and Postmortem Alcohol

• Chronic alcoholism — hepatic: fatty liver, alcoholic hepatitis and cirrhosis with portal hypertension; neurological: wernicke encephalopathy (the triad of ophthalmoplegia, ataxia and confusion) and korsakoff psychosis (irreversible short-term memory loss with confabulation), both from thiamine deficiency; peripheral neuropathy; cerebellar degeneration; delirium tremens on withdrawal; cardiomyopathy; pancreatitis; and fetal alcohol syndrome — growth restriction, microcephaly, a smooth philtrum and thin upper lip, and intellectual disability
• Methanol — the "hooch tragedy": illicitly distilled liquor contaminated or adulterated with methanol causes recurrent mass-casualty outbreaks in India. Methanol itself is relatively harmless; it is metabolised by alcohol dehydrogenase to formaldehyde and then formic acid, which is the toxin. Hence a latent period of 12 to 24 hours, longer if ethanol was taken with it. Features: severe high anion gap metabolic acidosis; and the characteristic visual disturbance — blurring, "snowfield vision", hyperaemia of the optic disc and then permanent blindness from optic atrophy; with putaminal necrosis on imaging. Treatment: ethanol or fomepizole to compete for alcohol dehydrogenase, sodium bicarbonate, folinic acid to accelerate formate breakdown, and haemodialysis
• Postmortem alcohol production — putrefactive organisms ferment glucose and generate alcohol after death, reaching levels of up to about 200 mg/dL in a decomposed body. To distinguish it: take vitreous humour and urine, which are protected from bacterial contamination; use fluoride preservative; take blood from a peripheral (femoral) vessel rather than the chest cavity; and note that the presence of other fermentation products such as n-propanol indicates postmortem production

Alcohol and the Motor Vehicles Act

• Section 185 of the Motor Vehicles Act makes it an offence to drive with a blood alcohol exceeding 30 mg per 100 mL, or while under the influence of a drug to such an extent as to be incapable of exercising proper control. The Amendment Act of 2019 substantially increased the penalties
• Section 203 empowers a police officer to require a breath test, and refusal is itself an offence and grounds for arrest without warrant
• Section 204 provides for a laboratory test of blood, to be taken by a registered medical practitioner; and a person arrested may request such a test, which is a safeguard against a faulty breath reading
• The evidential requirements — the time of the incident and of the sample; a non-alcoholic skin preparation; fluoride and oxalate preservative; a sealed container with the doctor’s seal and an impression of it; and an unbroken chain of custody. A defect in any of these is the commonest ground on which such prosecutions fail
• The doctor examines and reports; the officer prosecutes. The medical opinion addresses capacity — whether the person was capable of exercising proper control — and whether any illness or injury could account for the findings

Applied Aspects

• Never clean the skin with spirit before taking a blood alcohol sample; use an aqueous antiseptic, and record that you did
• Check the blood glucose in every intoxicated patient, and examine for head injury; the smell of alcohol is not a diagnosis and both errors are fatal
• Give thiamine before or with glucose in any chronic drinker; glucose alone precipitates Wernicke encephalopathy, which is preventable and irreversible
• Suspect methanol in a cluster of visual loss and severe acidosis after illicit liquor, and treat with ethanol or fomepizole immediately; the latent period means the patient may present feeling well
• Use vitreous and urine in a decomposed body; blood alcohol alone is uninterpretable once putrefaction has begun, and fluoride must be used in every sample
• Give the opinion in the statutory form — whether the person is incapable of taking care of themselves — and state expressly whether illness or injury could explain the findings
• Back-calculate with caution and state the assumptions; zero-order kinetics permit it, but the elimination rate varies substantially and the calculation is regularly overstated in evidence
• Zero-order kinetics remove a constant amount per hour, about fifteen to twenty milligrams per decilitre, which permits back-calculation
• Women reach a higher level from the same drink, because the distribution factor is lower, and the Widmark formula reflects this
• The Indian legal driving limit is 30 mg per 100 mL under the Motor Vehicles Act, and refusal of a breath sample is itself an offence
• Korsakoff psychosis is irreversible where Wernicke encephalopathy is not treated, which is why thiamine precedes glucose
• Fetal alcohol syndrome gives a smooth philtrum and thin upper lip with microcephaly and intellectual disability
• Putrefaction generates alcohol after death, so vitreous and urine are taken and fluoride is used in every sample
• Do not certify a person drunk; the opinion is whether they are incapable of taking care of themselves
• N-Propanol in the sample indicates postmortem production, and is a useful marker where fermentation is suspected
• Exclude head injury, hypoglycaemia and ketoacidosis before attributing a confused state to alcohol; the smell explains nothing
• Methanol is metabolised to formate, which causes both the acidosis and the blindness, and ethanol blocks its formation
• Treat a hooch outbreak on exposure alone; the latent period means the patient may present entirely well and go blind later
• Peak level is at thirty to ninety minutes, delayed by food, which bears on the interpretation of a sample taken soon after drinking
• A habituated drinker eliminates alcohol faster and survives far higher levels, so no figure is absolute in either direction
• Delirium tremens follows withdrawal at two to four days, and is a medical emergency distinct from acute intoxication
• Record the examination findings, not a conclusion; gait, speech, Romberg and finger-nose are what the court will read
• Refusal of a breath test is itself an offence under section 203 of the Motor Vehicles Act, and grounds for arrest without warrant
• An arrested person may request a blood test under section 204, which is a safeguard against a faulty breath reading
• Procedural defects are how these prosecutions fail — the antiseptic, the preservative, the seal and the timing all matter
• Alcohol potentiates sedatives and opioids, and that combination accounts for a large share of accidental deaths