Medico-legal importance of alcohol and its effects on the human body, various stages f alcohol intoxication and their effects on the human body. The absorption and elimination of alcohol by the body.

1. Alcohol & Alcoholism
Sardar Faizan
4th year MBBS
Islamabad Medical & Dental College

2. Introduction
• Alcohol is derived from the word “Al kohl” (Surma) which is a fine metallic
powder used in Muslim tradition believed to have medicinal properties.
• To a chemist the word alcohol refers to a group of compounds possesing
OH group.

3. Medicolegal importance of alcohol
• There may be no other chemical substance more frequently involved as a
contributory or causativr factor in violent or natural deaths and sometimes
even non fatal accidents.

4. Alcohol Misuse
• Alcohol misuse – term used to denote a persons uncontrolled driking
habbits which cause social, psycological and physical problems.
• Serum markers of alcohol misuse include
1. Gamma glutamyl tranferase (>40IU/L)
2. MCV (>91fL)
3. Uric acid (>7mg/dL)
4. Triglycerides (>180mg/dL)

5. Alcohol concentrations
• The measure of alcohol in urine and blood is mostly expressed as the weight
of alcohol per volume of diluent(w/v). (mg of alcohol per 100ml of blood)
• In breath it is measured as micrograms per 100 ml.
• Commercial preperations of alcohol is given in v/v
• The strenght of common drinks are

6. ½ pint of beer 3-8%

7. A glass of wine 8-14%

8. A glass of sherry 17-23%

9. Measure of spirits (vodka,gin..)40-55%

10. Shaked not stirred please

11. Consumption, absorption and Elimination of
alcohol
• Consumption; almost always voluntary and as a alcoholic beverage. Cases
may arise of accidental or unintentional consumption in cases cough syrups
amd elixers
• Absorption
• Maximun absorption pccurs at duodenum amd jejunum follwed by gastric mucosa (a
fatty meal may delay absorbtion)
• Absobtion is hastened when alcoholic beverages are mixed with carbonated drinks.

12. Absorption continued
• The absorption is optimum at concentrations of 20% (v/v)
• Ethanol is almost insoluable in fat so women may develop blood alcohol
concentations 25% higher for the same amount of drinks when compared
to men with similar body weight.
• Maximum blood alcohol concentrations are reached in 30-90 minutes after
ingestion.
• ROUTE – portal vein – liver – IVC - heart – systemic circulation

13. Elimination
• 90% alcohol is eliminated by the body as a result of oxidation by the liver.
• 10% is through the kidneys , lungs and skin.
• There are 2 pathways of oxidation
• ADH and ALDH
• MEOS

14. ADH and ALDH system
• In the liver alcohol is converted to acetaldehyde by the action of Alcohol
dehydrogenase (ADH)
• Acetaldehyde is a toxic compund and by the and is converted to acetyl
coenzyme A and acetate by the action of aldehyde dehydrogenase
(ALDH)
• Acetate enters the krebs cycle for energy production and is concerted to
CO2 amd H2O

15. Importance of acetaldehyde in aversion(‫)نفرت‬
therapy
• Administration of disulfiram patients suffering from alcohol misuse
interferes the oxidation of alcohol at the acetaldehyde stage
• This causes palpitations, flushing, headache, vertigo, vomiting and abdominal
pains.

16. MEOS
• Microsomal ethanol oxidising system – responsible for 10% of oxidation
• Chronic alcoholics adapt by an increase in activity in this pathway to lower
BAC faster.

17. Alcohol intoxication
• 3 stages
1. Stage of excitment
2. Stage of incordination
3. Stage of narcosis ‫بےحسی‬

18. Stage of excitment. BAC 50-150mg%
• A feeling of well being and pleasure
• Due to lowering of inhibition centres the persons speech and actions are less
restrained
• Also known as flippant stage and a person “smiles more readily and
becomes agry easily”
• Face is flushed, conjuntivae injected, pupils dilated and sluggish light and
accomadation refelexes.
• Recall memory is often disturbed

19. Stage of incoordination. BAC 150-300mg%
• Incoordination of thought, speech and action
• Speech; slurred amd incoherent
• Action; unable to perform any skilled action(driving) amd reaction time is
increased ( ‫بریک‬‫دیر‬‫سے‬‫لگائے‬‫گا‬ ) may be loss of facial muscle tone giving
“owlish” facial look
• May suffer from blurred vision, dry mouth, nausea and vomiting
• May even become gay, morose(‫)اداس‬ and irritable

20. Stage of narcosis. BAC >300mg%
• Also known as stage of coma
• Person goes into deep sleep and only responds to strong stimuli
• Fine lateral nystagmus is seen
• Madullary paralysis supervenes shoeing slow respiration, cold cyanotic skin,
dilated pupils and abloshed reflexes.

21. Fatal dose and fatal period
• BAC of 400-500mg% is sufficient to cause death
• Death may occur in 12-24 hours but may be dealyed for a few days

22. Diagnosis
1. Odour of breath
2. Slugish pupillary reaction
3. Slurred speech
4. History of alcohol intake
5. BAC

23. Preservation of samples
• Blood is frequently the sample of choice
• Do not clean the injection site with ethyl alcohol
• Dry swabbing or with isopropyl alcohol is advised
• During autopsy blood should be collected from peripheral vein
• During autopsy if blood is taken from the heart, massage the heart prior to
taking the same to ensure mixing of contents in chambers. This will avoid
having high or low hematocrit.

24. • In putrefied bodies be careful not to label the deceased as a drunk, several
reactions by putrfying bacteria cause the formation of alcohol in the body. A
BAC of about 40mg/100ml is not enough to label the person being drunk
during the time of death
• In such cases urine and samples of aq humor should be taken
• Sodium floride and phenyl mercuric nitrates are used as alcohol stabilizers.

25. Drug Dependence
• Stages
1. Tolerence
2. Withdrawl
3. Desire

26. Methanol
• It is a colourless liquid with a faint spirituous odour and burning taste
• Destructive distillation of wood or molasses
• It is used to make rectified spirit(90% ethanol) non drinkable
• Methylated spirit constituting of 95% ethanol and 5% methanol.
• Mostly taken by poor sections of society because of easy avaiablity and low
price

27. MOA
• Similar to that of ethanol
• ADH converts methanol to formaldehyde which im turn is converted to
formic acid by ALDH.
• The rate of elimination of the products of methanol metabolism is 1/5th
as compared to those of ethanol
• BAC of 80-100mg% can be fatal

28. Clinical features
1. Vertigo
2. Headache
3. Nausea
4. Vomiting
• Retrobulbar neuritis
1. Toxicity of formaldehyde on retinal cells causes partial or total blindness,
photophobia, snowfiled vision.

29. Management
• Gastric lavage
• Bicarbonate to combact acidosis
• Ethanol is the antidote
• Protect the eyes from light
• haemodialysis

30. Fatal dose and Fatal Period
• 70-140ml
• 24-36 hours