Lecture 19 - Poisons Flashcards
Describe carbon monoxide
- gas
- colorness
- odorless
- tastless
- slightly lighter than hair
sources of carbon monoxide
- endogenous
- incomplete combustion of fossil fuels and carbon-containing compounds (car exhaust from older cars or fires)
- exposure to methyl chloride (solvent in paint stripper)
- some drug therapy (phenobarbital)
metabolism/elimination of carbon monoxide
primarily eliminated unchanged by the lungs
carbon monoxide poisoning causes ____ ______
tissue hypoxia
Describe carbon monoxide levels (percent saturation)
1-10%: no detrimental effect (common esp if you live in urban centre)
5-9%: smoker level
10-20%: slight headache
20-30%: throbbing temples
30-40%: severe headache, weakness, dizziness, n/v, collapse
40-50%: retinal hemorrhages, increased respiration
Over 50%: convulsions, coma, death
What 3 spots are most sensitive to oxygen deprivation?
CNS, brain, lungs
Who is most susceptible to CO poisoning?
- infants
- those with lung disease
- those with CV disease
- elderly
- those with anemia
What is the treatment of carbon monoxide poisoning?
- remove person from source of carbon monoxide
- hyperbaric oxygen
- 100% oxygen, their CO2 level will drop by 1/2 within 40 minutes
- Air has 20% oxygen - will take about 4 hours to get the level to drop by 1/2
What can we use for analysis of carbon monoxide?
whole blood: need RBC’s
liver or kidney can also be used bc they have hemoglobin
What is the lethal dose of cyanide?
2mg/kg
What forms does cyanide come in?
- Hydrogen cyanide (HCN)
- colorless gas or blue-white liquid
- Cyanide salts ex. KCN, NaCN
- white crystalline powder
sources of cyanide?
- normal metabolism
- cigarette smoking
- fumigants, insecticides
- electroplating industry
- dying, printing, photography
- combustion of N-containing compounds
- cyanogenic glycosides
Describe the toxicity of cyanide
- an enzymatic poison
- attacks the cytochrome system
- prevents oxygen utilization at the cellular level (cytotoxic anoxia)
- results in metabolic asphyxiation
Describe the symptoms of acute toxicity of cyanide
- giddiness
- stiffness in lower jaw
- rapid, slow, irregular breathing
- muscle twitching
- palpitations
- cyanosis
- convulsions
- coma
- death due to respiratory arrest
____ and ____ are most sensitive to cyanide toxicity
brain and heart
Describe the chronic toxicity of cyanide
- dizziness
- weakness
- congestion of lungs
- conjunctivitis
- loss of appetite
- weight loss
- mental deterioration
Describe the max ppm of cyanide that you can get in an 8 hour work day and the ppm’s that cause death
Max 10 ppm over an 8 hour day
110 ppm = death in 1 hour
135 ppm = death in 30 min
180 ppm = death in 10 min
270 ppm = immediately fatal
Ingestion of cyanide: death may be delayed as long as ___ hour
1
What is the treatment for cyanide poisoning?
- Body can detoxify CN on it’s own
- Cn –> SCN- (via the rhodanese enzyme)
- cyanide –> thiocyanide
- this is an inefficient system; can be sped up by adding an exogenous source of sulfur
- 3 agents used: amyl nitrite; sodium nitrite; sodium thiosulfate
- thiocynate is water soluble and excreted in urine
if a house fire happens, what produces CO2 and what produces cyanide
wood: CO2
synthetic furniture: cyanide
What do we need to interpret cyanide?
-whole blood
What are inhalants?
What does that include?
defined as breathable chemical vapours that produce psychoactive (mind altering) effects
Includes: 1-volatile solvents 2-aerosols 3-anesthetics 4-volatile nitrates
What are some examples of volatile solvents?
Common sources?
- toluene
- methylethyl ketone
- acetone
- benzene
- naptha
- trichloroethane
- methylene chloride
Common sources:
- paint or paint thinner
- cement/glue
- lacquer thinner
- nailpolish remover
- lighter fluid
- dry cleaning fluids
- gasoline
Examples of aerosols and common sources
Ex. fluorocarbons
Common sources:
- hairspray
- cooking spray
- deodorant sprays
- glass chillers
- spray paint
Examples and sources of anaesthetics
- nitrous oxide
- ether
- chloroform
- halothane
Sources:
- propellant in whip cream containers
- anaesthetic used in dentristry and surgery
- solvent
Examples and sources of volatile nitrites
ex. amyl nitrite, butyl nitrite, isobutylene nitrite
sources:
- room odorizers
- tape head cleaner (past)
- used medically to dilate blood vessels
street names for inhalants
- sniff
- amys
- head cleaner
- hippie crack
What are the two ways to get exposure to inhalants
- intentional abuse
- occupational exposure
what are methods of exposure of inhalants
- inhalant (most common)
- oral ingestion or liquid
- skin contact
Sniffing
directly inhaling from container or heated pan or from piece of clothing soaked with solvent
Huffing
holding solvent soaked rag over face and breathing in through mouth
Bagging
spraying or pouring the solvent into a plastic bag, holding over mouth and nose and inhaling from the bag
Describe the stimulant phase of sniffing
- euphoria
- excitement
- release of inhibitions
- floating sensations
- delusions of grandeur and invincibility
How long does stimulant phase last for
15-30 mins typically but may be up to 1 hour depending on the agent used
Describe the depressant phase of sniffing
- drowsiness
- slowed reflexes
- stupor
- bizarre thoughts
- visual/auditory hallucinations
- inebriation similar to alcohol intoxication
How long does depressant phase last for?
up to 1-2 hours after cessation of sniffing
What are some general indicators of inhalant use?
- odor on breath or clothing
- excessive nasal secretions
- red watery eyes
- dilated pupils
- rapid involuntary eye movements
- complains of double vision, ringing in the ears, vivid dreams, hallucinations
- slow, slurred speech
- overall intoxicated appearance, confused, disoriented
- white powdery ring of dried glue around mouth, lmao obviously
- drooling, sores around mouth
- paraphenalia such as glue tubes, balloons and plastic bags with traces of glue or paint on them
Describe the pharmacokinetics (ADME) of inhalants
- inhaled vapours enter the bloodstream directly from the lungs
- rapidly distributed to the brain and liver
- some inhalants are metabolized and excreted by the kidneys; others are eliminated unchanged via the lungs
- stored in the fat tissues and slowly released back into the blood
long term effects of sniffing
- fatigue
- chronic headache
- dizziness, depression
- irritability
- loss of concentration and memory
- loss of appetite
- tremor
-liver, kidney, and brain damage
Tolerance of sniffing?
yes
Dependence of sniffing?
psychological dependence only
What is sudden sniffing death?
- Also called “sudden cardiac death”
- typically follows strenuous exercise or undue stress after several deep inhalations of “sniff”
- is caused by heart failure resulting from severely irregular heartbeat
- associated with halogenated hydrocarbons (ex. Freons)
