ChemPath: Drug, Forensics and Toxicology
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What sorts of deaths are reported to the coroner?
• Violent • Unnatural or sudden • Cause of death is unknown A number of these require analysis for drugs and alcohol in order to establish the cause of death
What sorts of case types are reported to the coroner?
• Addicts / drug use • Sudden unexplained / natural • Hanging • Overdoses • Road Traffic Collisions • Train deaths • Self-inflicted injury • Fire
What samples do coroners take?
• Ante-mortem serum / blood • Post-mortem blood • Femoral vein blood (screening and quantitation) preferred • Heart blood, cavity blood (screening) • Urine (UDS) • Stomach contents • Vitreous humor • Hair (timeframe for drugs) • Liver (when nothing else available) • Others – bile, muscle, powders, syringes
Techniques used for analysis and screening in toxicology
Gas and Liquid chromatography
What is the most common drug problem?
Alcohol
What are the main problems associated with alcohol?
• OD • Accidents including RTCs • Additive effects other respiratory depressant drugs
What are the main problems associated with heroine?
• IV injection, volatilised • Fatal OD with both routes of ingestion • Additive effects other respiratory depressant drugs • Few rapid deaths • Most respiratory depression or aspiration pneumonitis • Tolerance
What is toxicology?
Concerned with anaylsing samples of drugs/poisins and interpreting the significance of the results.
What does ‘forensic’ mean?
Results/reports used in court
Why might drug levels appear erroneoously elevated post-mortem?
Tissue breakdwon can lead to the release of drugs from various tissues
Where can a sample be taken from for drug concentration measurement?
Femoral vein blood
When is vitreous humour used as a sample?
Used to measure glucose (may be elevated in DKA)
How can heroin overdose kill?
Respiratory depression or aspiration pneumonitis
What are the acute dangers of cocaine?
• Cardiac dysrhythmias • Acute heart failure • MI
What is the effectof mixing ethanol with cocaine?
Forms cocaethylene which prolongs the effects of cocaine
What happes to cocaine in post-mortem blood?
Breaks down rapidly so the concentration in post-mortem blood may be considerable lower than at the time of death.
Describe the consequences of amphetamine overdose.
Causes hyperthermia → rhabdomyolysis → renal failure Also has a direct toxic effect on the heart
List some examples of legal highs.
• Stimulats (e.g. bath salts) • Synthetic cannabinoids • Synthetic opioids (e.g. acetylfentanyl) • Hallucinogenic compounds
How long can drugs be detected for in the: • Blood and serum • Urine • Hair
• Blood and serum = 12 hours • Urine = 2-3 days • Hair - months/years
Why can you do Drug screens using hair?
Drug is fixed to hair at root during growth phase So can be analysed on hair as it grows out of root at 1cm/month Length of hair is effectively a timeline
How are hair samples used in forensic toxicology?
• Demonstrating a history of drug use or lack of it • Demonstrating tolerance or lack of tolerance to drugs (helps interpret post-mortem drug concentrations) • Compliance with medications (e.g. antipsychotics) NOTE: hair samples are rarely used in coroner’s toxicology but it is used in forensic investigations
What are the issues with hair analysis?
• Environmental contamination • Absorbed from sweat or sebum coating the hair • Passive inhalation • Cosmetic treatment (e.g. shampoo) • Hair colour
What are the two causes of death due to cocaine use?
• Depression/suicide due to long term cocaine use • Sudden unexplained death
What are the main drugs used in chemsex?
GHB Methylamphetamine (crystal meth) Mephedrone