Effects of alcohol Flashcards
20mg/100ml of blood (1 unit)
-disinhibition, euphoria, emotional insatbility, release of social and sexual inhibitions
80mg/100ml of blood
-more pronounced previous effects, motor coordination becomes more affected, marked effect on judgement
200mg/100ml of blood
-motor coordination is progressively lost and speech becomes slurred
300mg/100ml of blood
unconsciousness
400mg/100ml of blood
death from respiratory failure
Pharmacokinetics of alcohol
- rapidly absorbed from mouth, lung, stomach, small intestine (peak blood conc. in 30-60minutes)
- cleared from the body mostly by metabolism (liver)
Alcohol dehydrogenase (ADH)
CH3CH2OH + NAD+ –> CH3CHO + NADH
Clearance
- Zero order with respect to ethanol
- ethanol cleared at constant rate regardless of concentration therefore easy to calculate
Detection of alcohol in breath
Breath intoximeter - IR/EC detection of alcohol in expired air
Detects mouth alcohol and interfering substances
Detection of alcohol in blood
- Gas chromatography of extracted blood sample with IR/EC detector
- eliminates cross detection of other substances
Road traffic Act 1988
Section 4 (i) driving a motor vehicle whilst unfit through drink or drugs Section 4 (ii) being in charge of a vehicle whilst unfit through drink or drugs
Forward and Back calculation of alcohol conc
NEED
- height and weight of subject
- amount of alcohol consumed
- when alcohol consumed (start time)
- Intoximeter and/or blood sample readings
- what times values needed for
Procedure -alcohol
- police stop suspect
- detect alcohol (smell)
- roadside breath test
- if positive -arrest
- intoximeter procedure
- if <40 release without charge
- if >50 charge
- if 40-50 - take blood/urine sample
Lines of defence (Section 5 - alcohol)
- statutory defence - no intention to drive - need calculation of when subject would fall below statutory limit
- post incident drinking - need calculation to verify consistency of evidence
Section 5 (Alcohol) cont,
Spiked drinks - calculations required to verify evidence
MEDICAL IMPACTS OF ALCOHOL
Types of death involving alcohol:
- acute intoxication
- chronic alcoholism
- accidents
- suicides
- homicides
post mortem examination
-history, external, internal, samples (N.B. Femoral artery/vein)
Acute alcohol intoxication
- > 300mg/100ml blood = increasing danger of death
- direct respiratory depressant effect on the brainstem
- aspiration of vomit
- cardiac arrhythmia
- trauma
- fire deaths
- drowning
Post mortem findings
- usually only congestion of the lungs
- vomit in airways
- evidence of chronic alcoholism
- pre-existing disease
- traumatic injury
- burns?
Chronic alcoholism
- extremely potent drug
- all systems of body are affected
- bulbous nose
- bruises
- jaundice/spider naevi/gynaecomastia
- ascites/oedema
jaundice
- accumulation of bilirubin in the skin
- breakdown product of haemoglobin (Hb)
- damaged liver cells (hepatocytes) do not function adequately
Ascites
- accumulation of fluid in the abdominal cavity
- due to portal hypertension and decreased proteins in blood (albumin esp.)
spider naevi
- skin lesion
- small central blood vessel with radiating smaller vessels
- affects the face, chest and upper limbs
- sign of chronic liver disease
Internal - C.N.S
- intracranial bleeding
- cerebellar atrophy
- wernicke-korsakoff psychosis (nystagmus, ataxia, amnesia, confabulation, hallucinations)
- delerium treatments
Intracranial bleeds
- subdural haemorrhage
- extradural haemorrhage
- intracerebral haemorrhage
extradural haemorrhage
- space between skull and dura
- skull fractures (site? vessel?)
- lucid interval
- neurosurgical drainage is necessary
subdural haemorrhage
below the dura
intracerebral haemorrhage
- increased risk of haemorrhagic stroke if clotting is abnormal and the vessels are inherently weakened
- increased risk of hypertensive stroke
Internal - cardiovascular system
- increase in blood pressure
- alcoholic cardiomyopathy (dilated chambers, enlargement of the cardiac myocytes, patchy fibrosis in the interstitium)
Internal - gastrointestinal system
- gastric ulcer/gastritis
- mallory-weiss tear
- pancreatitis (acute/chronic)
- malabsorption
Pancreas
- “dual purpose” gland
- endocrine portion :Islets of Langerhans (Hormones: Insulin, glucagon, somatostatin)
- exocrine gland: 99% of pancreas, many digestive enzymes, bicarbonate ions
Pancreatitis
- direct toxic effects
- acute - pain/nausea/vomiting/metabolic/shock/death
- acute - haemorrhagic / necrotic pancreas
- chronic - pain/weight loss/malabsorption / diabetes
- chronic -fibrotic
Internal examination - LIVER
- alcoholic hepatitis
- fatty degeneration (enlarged smooth liver)
- cirrhosis (Fibrous bands, nodules, 60-70% of Western world due to alcoholism)
- portal hypertension (restriction of blood flow, increased B.P., back pressure - dilated veins, oesophageal varices)
- liver failure
Portal hypertension (liver)
- Splenomegaly
- ruptured varices
- haematemesis
- black stools
- haemorrhage - can be fatal
