Alcohol Flashcards by Rosie Middleton

What is alcohol

OH group attached to carbon chain

Ethanol in alcoholic drinks

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Spectrum of alcohol use

Teetotal = 10%
Sensible/social drinker
- 14units/week
Heavy drinker
- men > 7 , women > 5 units/day
Problem drinker
- continues drinking whilst having problems in their life
Dependent drinker
- > 8-10 units/day

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Levels of alcohol drunk

Sensible < 14 units/week
Hazardous > 14 units/week
Dangerous > 35 u/w

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Cost equation of alcohol in society

Debit - £2bn
- absenteeism
- unemployment
- offences
- RTA
- health
- premature death
Credit - £7bn
- excise duty
- exports
- jobs

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Alcohol as a factor in social harm

20% of RTAs
25% of drownings
30% of accidents
35% of divorces and child abuse
40% of domestic violence
50% of murders
60% of head injuries
70% of suicides
80% of fire deaths

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Features of alcohol dependence

Aware of compulsion to drink
Prominent drink seeking behaviour
Tolerance to its effects
Withdrawal syndromes on stopping
Avoidance of withdrawal 
Social psychological and physical problems
Criteria
- heavy drinking - > 10u/d
- tolerance
- withdrawal syndromes
- inability to stop drinking
- abnormal blood tests - GGT, CDT, MCV

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Average content of alcoholic beverages

Alcohol content expressed as % alcohol by volume
- 4% = 4ml/100ml beer
1ml alcohol weight 0.79g
Amount alcohol (ml) = volume consumed (ml) x % ABV
1 unit = 10ml or 8g or pure alcohol
1unit =
- half pint of weak beer (3.5%)
- small (<100ml) glass wine (12%)
- small (28ml) measure of sprits (40%)
1 unit = amount of alcohol (ml) x 0.79 / 10

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Factors affecting absorption of alcohol

Gastric emptying accelerated - increased absorption
- tolerance
- gastrectomy
Gastric emptying slowed - reduced absorption
- food in stomach
- drugs

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Absorption of alcohol

20% from stomach
80% from small intestine
Rate of alcohol absorption depends on rate of gastric emptying
Food reduced rate and extent of absorption - 2/3 fasting value
Depends on type of drink - strength, effect of congeners
- 10-20% optimal
- champagne absorbed quick - high conc and bubbled
- beer absorbed slow - low conc, congeners
- neat spirits irritate stomach - mucus delays absorption
Absorption complete within 1-3 hours

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Kinetics of alcohol

Absorption phase
Distribution phase
- peak = Cmax ( max concentration)
- 15mg/100mls from 1 unit on empty stomach
Elimination phase
- mostly by liver
Tmax = time at max concentration
C0 = hypothetical track back of max concentration if all absorbed instantly
= weight alcohol consumed x 100 / body weight x widmap factor
W.F = measure of body water
= 0.6 roughly

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Rate of elimination

= 10-20mg alcohol / 100ml blood / hour

About 1 unit per hour

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Calculate blood alcohol levels

C at T hours = C0 - (rate of elimination x number of hours)

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Breath alcohol

1-2 hours after drinking

BAC:BrAC = 2300:1

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Vitreous humour alcohol concentration

During absorption BAC > VHAC
At equilibrium BAC < VHAC (ration 0.8)
- due to higher water concentration in VH
- takes longer to get into VH
Cannot reliably predict BAC from VHAC
VHAC corroborates BAC conc

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Urine blood alcohol concentration

Urine collects in bladder over several hours

UAC average of several hours of excretion
UAC < BAC during absorption phase
UAC > BAC during elimination phase

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Distribution of alcohol

Dissolves in water
Distributed by bloodstream
Taken up by tissues in proportion to water content
- more alcohol removed from blood into water rich bone and muscle
- less alcohol removed from blood by fatty tissue
- those more lean able to take up more alcohol for lower BAC

Factors affecting blood alcohol concentration

Depends on
- how much alcohol consumed 
- volume of distribution
= mass consumed / volume of distribution
Lean body mass = Wt x WF

What is Widmark Factor

Gives rough estimate of BAC after alcohol - assumes instantaneous 100% absorption
Factor is proportion of body water
- 0.68 for M and 0.55 for F
- calculate from online chart

Calculate BAC (Co)

Weight alcohol consumed (g) x 100
/
Body weight (g) x W.F

C at T hours = C0 - ( elimination rate x T)

Conversion factors for body fluids

BrAC = BAC / 2.3
UAC = BAC / 0.75
VHAC = BAC /0.8

Legal limit for driving

35 (E) or 22(S) micrograms alcohol / 100ml breath

80 (E) or 50 (S) mg alcohol/ 100ml blood

Elimination of alcohol

90% broken down in liver
Small amounts lost in 
- breath - 2-5%
- sweat - 2-5%
- urine - 2-5%
Rate of elimination (b) is 10-20mg per 100ml blood per hour
- average 15 mg/100ml/h = 1 unit/ hour
- up to 40 in alcoholics
Amount eliminated in T hours = (b x T)

Alcohol metabolism

Ethanol -> acetaldehyde
- by alcohol dehydrogenase
Acetaldehyde -> acetate
- by aldehyde dehydrogenase
Releases CO2 and H2O
Forms uric acid, ketones and triglycerides

Stages of intoxication

Excitement - BAC < 100mg%
- depression of higher inhibitory cortical function
Confusion - BAC 100-200mg%
- depression of limbic system - memory, orientation
- depression of cerebellum - coordination, speech
Stupor - BAC > 200mg
- depression of upper BS - RAS - conscious level
- depression of lower BS - breathing and vasomotive centres

Acute intoxication may mimic

``` Head injury Neurological disease Diabetic hypoglycaemia Epilepsy and related states Drug intoxication ```

Features of hangover

Toxic effects of alcohol metabolites and congeners on brain and GIT Headache, malaise, nausea, tremor Temporary and self-limiting Dehydration and hypoglycaemia worsen

Effect on alcohol on performance

``` Decreased muscular control and coordination Increased reaction times Impaired peripheral vision Inability to judge speed and distance Inability to deal with unexpected Falsely increased confidence ```

Features of alcohol dependence

``` Aware of compulsion to drink Prominent drink seeking behaviour Tolerance to its effects Withdrawal syndromes on stopping Avoidance of withdrawal Social, psychological and physical problems ```

Factors leading to alcoholism

``` Constitution - low self-esteem - habit - boredom - loneliness - anxiety and depression - ethnicity Environment - availability - peer pressure - occupation - stress - competitive lifestyle - unemployment ```

Features of alcohol withdrawal

Uncomplicated - onset 6-12 hours - peak 48 hours - lasts few days - features tremor, N+V, malaise, headache, insomnia, weakness, sweating, tachycardia, hypertension, anxiety, depression, irritability, transient hallucinations

Causes of death in alcoholics

Acute alcohol intoxication Trauma Alcohol related disease Incidental natural disease

Physical complications of alcohol

``` GIT - oesophagitis - Mallory-Weiss tears - gastritis - duodenitis - peptic ulcer - malabsorption - diarrhoea - pancreatitis Liver - fatty change - alcoholic hepatitis - cirrhosis - liver failure - portal hypertension and oesophageal varices - liver cancer CVS - arrhythmias - sudden death - alcoholic cardiomyopathy - hypertension CNS - Wernicke's encephalopathy - Korsakoff's syndrome - cerebellar degeneration - cerebellar atrophy - alcoholic dementia - alcoholic hallucinosis - peripheral neuropathy Nutrition - early obesity - later malnutrition - vitamin deficiencies Metabolic - hypoglycaemia - hyperlipidaemia - hyperuricaemia - lactic acidosis ```

Fatal alcohol intoxication

``` Fatal level variable > 250mg% in non-tolerant person > 450 mg% in tolerant Urinary alcohol conc > BAC if death follows prolonged coma Mechanisms - brain stem depression - positional asphyxia - inhalation of vomit ```

Features of post-mortem alcohol resdistribution

Passive diffusion of unabsorbed alcohol from - stomach - aspirated vomit in airways To central vessels < 400% difference between central vessels and peripheral vein