Toxicology

“Having sniffed the dead man’s lips, I detected a slightly sour smell, and I came to the conclusion that he had

poison forced upon him.”

—Sherlock Holmes, in Sir Arthur Conan Doyle’s

A Study in Scarlet

Chapter 9

Toxicology

• marriage of chemistry and physiology that deals with substances and how they alter or harm living organisms (particularly humans)

Understanding Poisons

• Poison – any substance that, when taken in sufficient quantities, (relative to the compound) that causes a harmful or deadly reaction.

INTOXICANT vs. POISON• Intoxicant

– need very large amounts to be harmful (not typically considered a poison)

• alcohol• carbon monoxide• water

• Poison– requires only a small

amount to harm• cyanide

• lead

• etc...

• Acute Poisoning– Harmful with a small

amount over a short period of time

• cyanide• ricin

• Chronic Poisoning– Harmful with a small

amount over a long period of time

• mercury• lead

Dangerous Animals

• Venom – is injected or squirted – stored in venomous gland(s)

• Example: snake venom

• Poison – Exists in or on the organism

• Usually the result of the organisms diet

– No venom glands• Example: poisoned dart frog

milkweed

Box Jellyfish(Chironex fleckeri)

• Yup.. Its nasty!!!

Historical Toxicology

• 1st forensic toxicological test in 1775

• Matthew Orfilla 1813

• Foods safe for humans are not necessarily

safe for pets.

• Substances safe to consume may not be

safe to inject.

• Eating a peanut is life-threatening for

some.

Toxicology today

• Toxicologists job = to

find a toxins presence

or absence– BOTH are just as important

• Example: someone who’s exhibiting bizarre behavior but shows no drugs in body may lead to a psychiatric evaluation and hopefully appropriate treatment.

The toxicologists conundrum

1. Most poisons don’t cause visible changes to the body but are hidden within cells

• Therefore autopsy analysis from cursory viewing of organs doesn’t always lend help in determining a C.O.D.

2. Instead, M.E. collects fluids and tissues from the body that the toxicologist must analyze later

WHAT THE HECK IS THIS?

metabolism

Looking for Toxins• Biotransformation (a.k.a. metabolism) –

the result of a body destroying or breaking down chemicals in order to eliminate them– heroin > morphine

• QUESTION: What does it mean if you find morphine the body of someone that died a suspicious death?

Collecting Samples

• Best places to get samples– blood – urine– stomach contents– liver– vitreous humor – shows toxin amount in blood 1-2 hrs

before death

– hair – absorbs heavy metals AND creates a time line for use!

– insects – if they are “chowing” on a toxic body, the chemical ends up affecting the insects too

Understanding the Testing Procedures

• Presumptive– Cheap and easy to perform

• Color test– Reagent (chemical solution) is added to blood, urine, or tissue

• Gas chromatography (GC)– Separates compounds according to their respective sizes, shapes, and

chemicals BUT can’t give exact makeup

• Confirmatory– Used only after a presumptive test is positive– Expensive and time consuming– Confirm identity of specific drug(s)

• Mass spectrometry (MS) – Compares the mass spectrums of unknown and known substances– used in combination with GC.

» GC separates the test sample into components. MS identifies each of those components

Now the hard part

• Once a drugs presence is confirmed the ME must assess what the results actually mean– Was the drugs presence enough to cause the victim

to:• Loose control of a car• Exhibit violence• Cause death

Descriptive Levels• Normal – expected level in a population

under normal circumstances• Theraputic – the level a doctor wants you

to reach when taking a prescription medication (level in blood is most beneficial)

• Toxic – level can cause harm up to and including death

• Lethal – level that consistently causes death– “LD50” = lethal dose where 50% of people

die (measured in blood)

Where ME looks for toxins?

• Ingested toxins

• Inhaled• Injected (muscularly)

• Intravenously (IV)

• any

• Stomach, intestines, or liver

• Lungs• Around injection site

• thought entire body (blood)

• Hair (grows 1/2 inch per month) gives timeline

** Important **

• Note: Every little bit helps when trying to get to the bottom of a possible poisoning. The ME and toxicologist use any and all evidence to get to the bottom of a possible poisoning.

• Such as…..– Results of toxicological testing– Autopsy examination– Statements from investigating officers &

witnesses

• Know the chemical makeup, physiological actions, and byproducts of drugs and potential poisons

Looking at Common

Drugs

INDEX

1. CNS DepressantsA. alcohol

B. barbituates

C. opiates

2. Stimulants

3. Hallucinogens

4. Date-rape drugs

5. Inhalents

6. Steroids

1. CNS Depressants A

• make the user:– sleepy, lethargic, and suppress respiration

• physically addictive

1. CNS Depressants A.

• ALCOHOL– Ethanol = active ingredient– Physically addictive (causes withdraw)

• Delerium Tremens (DT’s) for 20% of users

Blood-alcohol levels • expressed as a number that shows % of alcohol in every

100ml of blood. – Example .08 (out of 1)

^ level of alcohol in blood = decreased of: • motor skills• Judgment• reaction time

1. CNS Depressants A• Alcohol legal limit

– Nothing - .08 is legal limit ( ^ .081 = jail)– % alcohol level in blood = % alcohol level in

breath

1. CNS Depressants A

• Exhaling the evidence– Indiana State Police Captain R. F. Borkenstein invented

Breathalyzer in 1954

2 parts to the breathalyzer1. Expired air destroys acetic acid in proportion to the

amount of alcohol from breath2. Then a Spectrometer measures the light reflected

off the remaining not destroyed ..

voila a # is given

What is a hangover?

• Vasopressin – chemical that inhibits mass flush of body fluids from kidneys to bladder– Loss of salt, potassium, electrolytes, & glycogen

(diuretic effect) - – Chemical Made by pituitary gland

• VEISALGIA – VEIS (NORWEGIAN) –DEBAUCHERY– ALGIA (GREEK) – PAIN

Hangover continued

• Glutamine – – naturally occurring stimulant produced by

body – inhibited by alcohol (hence the relaxation)– when one stops drinking the body over

produces glutamine to make up for lost time

voila .. Shortened sleep time.

• Brain actually shrinks & pulls on meninges

(connective tissue holding brain to skull)– (loss of available liquid to other “dried out”

organs)

1 Depressants B

• Barbituates – derived from barbituric acid– used as hypnotics or sleeping pills

• example: phenolbarbital (anticonvulsive) for individuals with epilepsy

– TEST USED = Color test screens for the presence of barbituates in biological tissue

• Blood• Urine• Organs

1. Depressants COpiates – chemicals derived from the sap of

poppies– Natural – morphine & codeine– Semi-synthetic – heroin (combining morphine with

acetyl chloride)– Synthetic – Made in a lab

2. Stimulants

• Stimulants– Why it’s addictive

• Increase alertness & energy• High doses induce euphoria, increase self- esteem, &

increase pleasure

– Positive physical effects• Increase dopamine, norepinephrine, and serotonin in the

brain (feel good chemicals)

– Negative physical effects• Numerous.. acne, convulsions, heart attack, stroke, & death

2. Stimulants

• Stimulants (aka: uppers or crank) – Methamphetamines (aka: meth)

• From acacia tree

– Cocaine• From leaves of the coca plant

– Ecstacy

3. Hallucinogens

• Mood altering– Delusion inducing (not based in reality)

• Create sensory experience that can be:– Visual – Auditory– Olfactory– Tactile– Taste

A man being talked off a roof ! !(real picture)

3. Hallucinogens

• Some examples of hallucinogens:– Marijuana (aka: mary jane, weed, pot, etc)

– From Cannabis Sativa plant

• Active ingredient– Tetrahydrocannabinol (THC)

» Body breaks THC down into 9-carboxyl-THC » Presumptive test: Duquenoise-Levine » Can test positive up to 2 months after exposure !

3 Hallucinogens

• Cacti and mushrooms– Peyote: small Mexican cactus

• Active ingredient: mescaline • Possession is illegal

– Mushrooms• Active ingredient: psilocin and psilocybin• Possession isn’t illegal ?!!?

3 Hallucinogens

• Lysergic acid diethalamide (LSD)

• Phencyclidine (PCP) aka. “angel dust” – Produces altered mental state up to 12 hrs– Not DIRECTLY fatal

• Test: Van Urk Color Test * * * CAN TEST POSITIVE UP TO A WEEK AFTER EXPOSURE * * *

4 Date-rape drugs

• cause – poor judgment– compliance– sedation– amnesia– coma– death

4 Date-rape drugs

• COMMON DATE RAPE DRUGS– Ecstacy (a stimulant)– Rohypnol– GHB– Ketamine

5 Inhalants

• Substance abuse where user inhales volatile chemicals – (a.k.a. huffing)

• Broad range of drugs – Classified by intended function

• Paint thinner• Gasoline• Nitrous oxide (laughing gas)

STEVE-O

• Giddiness

• Euphoria

• Dizziness

• Slurred speech

• Headache

• Nausea

• Vomiting

The face of huffing

Medical Examiner and inhalants

• b/c these chemicals are volatile, they break down rapidly in the body

• ME must determine COD by looking for damaged– Liver– Kidney– Lungs

Explosion in car injures 3 teensOctober 24, 2008

• Huffing , lighting cigarette to blame• Pierrette J. Shields and Jason

Gonzales,• LONGMONT — An explosion inside a car

that injured three teenagers Thursday afternoon was sparked when one of the girls lit a cigarette and ignited fumes from aerosol air fresheners the teens had been huffing, police said.

6 Steroids

• Steroids = a lipid (fat)– Naturally produced in the body

6 STEROID ABUSE

• Pros– Muscle growth – Increased strength

• Cons– Hair loss– Impotence– Liver damage– Aggressive behavior– “He Bosoms” – Shrunk testicles

ANOTHER SIDE EFFECT OF STEROID ABUSE

“BACKNEY”

Medical Examiner and steroids

• Suspicion begins when examined body has above average muscle mass

• Screening is difficult b/c steroids are always in the body naturally.