Download Forensic Toxicology

Toxicology
Chapter 9
Toxicology
• Toxicology: study of poisons and
drugs and their effect on the body.
• Poison: a naturally-occurring or
manufactured substance that can cause
severe harm or death.
– Toxin: a poisonous substance naturally produced
by certain plants, animals, and bacteria that is
capable of causing disease or death in humans.
(cont’d)
• Drug:
1) Any chemical substance that affects the
processes of the mind or body.
2) A substance used in the diagnosis, treatment,
or prevention of a disease.
3) A substance used recreationally
Ex. narcotic, hallucinogen.
Method of Administration/Exposure
1) Ingestion – substance is
eaten and transferred to
bloodstream through lining
of mouth, stomach, & small
intestine.
Method of Administration/Exposure
2) Inhalation – substance is inhaled into lungs
and absorbed into bloodstream during
respiration.
Method of Administration/Exposure
3) Injection – substance is
injected through the skin
(transdermal injection)
into muscle tissue
(intramuscular) or
directly into a blood vessel
(intravenous).
Method of Administration/Exposure
4) Absorption: substance is absorbed through
the skin and into the bloodstream.
Toxicity
• Toxicity: the degree to
which a substance is
poisonous or can cause
injury.
• Depends on these factors:
1.
2.
3.
4.
Dose (how much was taken)
Duration (frequency & length of exposure)
Method of exposure (ingested, inhaled, injected, absorbed)
Interactions with other substances in body (ex. alcohol or
prescription drugs)
How do you Test for the Presence of
Poisons & Drugs?
•
•
•
•
Body fluids (ex. urine)
Stomach contents
Internal Organs (ex. liver)
Vitreous humor fluid
of the eye
• Breathalyzer
• Hair
• Skin
When someone is poisoned,
investigators classify that exposure as...
• Intentional – Drugs taken to treat an illness or
relieve pain.
• Accidental – Unintentional overdoses or harmful
combinations.
– Ex. legal prescriptions (ex. pain killers) & alcohol (2:07)
Ex. heroin and alcohol (My 23-year-old cousin died of
this!!!)
• Deliberate – An exposure intended to kill/harm
someone; suicide.
History of Poisoning
• Greek Philosopher Socrates was one of the
earliest victims of poisoning.
• Found guilty of “refusing to recognize the gods”
and “corrupting the youth”, he was sentenced to
death by hemlock poisoning in 399 B.C
History of Poisoning
• Rich families & royalty of Europe used arsenic
& cyanide to settle disputes.
• Arsenic became a favorite murder weapon of the Middle
ages and Renaissance, particularly among ruling classes in
Italy.
– Because the symptoms are similar to those of cholera, which
was common at the time, arsenic poisoning often went
undetected.
– By the 19th century, it had acquired the nickname "inheritance
powder," perhaps because impatient heirs were suspected to
use it to accelerate their inheritances.
Poisoning
• Very common in literature, but not
a very common form of murder.
• Less than 0.5% of homicides result
from poisoning.
• Common poisons today include:
arsenic, cyanide, strychnine, and chemicals normally
used as fertilizers and antifreeze.
• Acute Poisoning: high dose over short time
– Ex. cyanide poisoning causes symptoms immediately
• Chronic Poisoning: low doses over longer time
– Ex. mercury and lead accumulate slowly in body and
produce symptoms gradually
Read Article:
Who Killed Alexander Litvinenko?
1.
2.
3.
4.
Who was Alexander Litvinenko?
Why was he poisoned?
What was he poisoned with?
What symptoms did he
experience?
5. What was the mechanism of
death?
6. Why did it take so long for
doctors to determine what
he was poisoned with?
Accidental Drug
Overdoses
• More common than deaths
from deliberate poisoning.
– Ex. Whitney Houston, John Belushi,
Heath Ledger, Chris Farley, River Phoenix,
Steve Clark, Janis Joplin, Jim Morrison,
Jimi Hendrix.
• In the News:
FDA to ban caffeinated alcohol drinks
– These drinks were banned in Nov. 2010.
Drugs and Crime
• Illegal Drugs: drugs with no current medical
use (Schedule 1).
– Ex. heroin, LSD
• Controlled Substances: legal drugs whose
sale, possession, and use are restricted
because of the effect of the drugs and the
potential for abuse.
– Ex. narcotics, depressants, stimulants
Federal Law
Potential
for Abuse
Used in
Medicine?
Examples
Schedule 1
Illegal Drugs
High
No
Heroin, LSD,
MDMA (ecstasy), marijuana
Schedule 2
High
Yes – but
restricted
Opium, Morphine, Codeine,
Oxycodone, Cocaine,
Amphetamine, Methamphetamine
Schedule 3
Moderate
Yes
Anabolic steroids, Ketamine,
Phenobarbital, Tylenol plus codeine
Schedule 4
Low
Yes
Diazepam (Valium)
Schedule 5
Low
Yes
Low-grade stimulants, low-dose
narcotics, cough suppressants
Drugs and Crime
• Arrests for drug abuse have been rising
steadily since the early 1990s.
– Drug offenders account for more than half of
federal prisons inmates & 20% of state prison
inmates.
Controlled Substances
• Five Classes of Controlled Substances:
1) Stimulants
2) Hallucinogens
3) Narcotics
4) Anabolic steroids
5) Depressants
Jigsaw Activity
• Read the article, outline specifics with regards
to each controlled substance.
• Share with group.
• You are responsible for understanding the
information on each of the 5 classes.
Other Organic Toxins
• Organic toxins – toxins produced by living organisms that will
interfere with another organism’s metabolism
• Examples:
1) Venom – bee sting, snake bite
2) Alcohols
– Methanol – not directly poisonous, but is converted by liver into
formaldehyde which is very toxic
– Ethanol – produced by fermentation of sugar in fruits, grains, and
vegetables
• The body converts ethanol into acetaldehyde which causes dehydration
when it accumulates in the blood (causing hangover symptoms)
• Chronic abuse causes liver damage, dangerous behavior, depression of
CNS, and permanent memory loss.
Other Organic Toxins
3) Bacterial Toxins
– Botulism
•
•
•
•
Produced by Clostridium botulinum
Found in contaminated food
Most poisonous biological toxin known to man
Paralyzes muscles by blocking the
neurotransmitter acetylocholine
• Botox is just purified botulinum toxin!
– Used to treat muscle spasms, eye conditions,
excessive sweating headaches, stimulate wound
healing, and as a cosmetic treatment
– Tetanus
• Produced by Clostridium tetani
• Causes deadly nervous system disease
• Causes muscles to spasm (starts as “lockjaw”),
interferes with breathing
Other
Organic Toxins
4) Pesticides & Heavy Metals
– Pesticides – ex. DDT, aldrin, dieldrin
• Carcinogens, thinning of bird eggs.
– Metals – lead, arsenic,
mercury (Mad Hatter’s Disease)
– Other lethal agents interfere with production of ATP
or destroying cell’s ability to transmit electrical
impulses:
• Hydrogen cyanide - gas chambers
• Carbon monoxide - car exhaust
• Potassium chloride or sodium pentothal - lethal injection
Other Organic Toxins
5) Bioterrorism Agents
– Ricin
• Waste product of the manufacture
of castor oil from castor beans.
• Prevents cells from making
proteins.
– Anthrax – inhalation of
endospores
• Produced by Bacillus anthracis
• 2001 – 22 cases of anthrax
infection from envelopes sent
through U.S. postal service, 11
deaths.