General Information on Poisons and Poisoning. Routes of Absorption, Local Effects, Systemic Effects

7/28/2019 General Information on Poisons and Poisoning. Routes of Absorption, Local Effects, Systemic Effects

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GENERAL INFORMATIONSON POISONS AND POISONING.

Routes of absorption

local effects

systemic effects


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WHAT IS A POISON?(from the Latin word - potare - meaning to drink)

Any subs tance that causes harm i f i t gets into the body

Harm can be mild (ex. headache or nausea)

or severe(ex. fits or very high fever),

and severely poisoned people may die.

Poisons can also enter the body: By breathingThrough the skin

By IV injection

From exposure to radiation

Venom from a snake bite

The amount of a chemical substance that gets into the body at one time =

the dose.

A dose that causes poisoning = a poisonous dose or toxic dose.

The smallest amount that causes harm = the threshold dose.


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Depends partly on how long the contact lasts

on how much poison gets into the body, and

on how much poison the body can get rid of during this time.

Exposure may be:

Acute exposure: a single contact that lasts for seconds, minutesor hours, or several exposures over about a day or less

Chronic exposure: a contact that lasts for many days, months oryears. It may be continuous or broken by periods when there is nocontact. Exposure that happens only at work, for example, is notcontinuous.

WHAT IS POISONINGExposure to a poison


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LIST OF POISONSa range of chemicals and their relative toxicity

Chemical Dose Type Target

water 8 kg inorganic nervous system

lead 500 g inorganic nervous system

alcohol 500 g organic kidney/liver

ketamine 226 g drug cardiovascular

table salt 225 g inorganic nervous system

ibuprofen (e.g., Advil) 30 g drug kidney/liver

caffeine 15 g biological nervous system

paracetamol (e.g., Tylenol) 12 g drug kidney/liver

aspirin 11 g drug kidney/liver

amphetamine 9 g drug nervous system

nicotine 3.7 g biological nervous system

cocaine 3 g biological cardiovascular

methamphetamine 1 g drug nervous system

chlorine 1 g element cardiovascular


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Chemical Dose Type Target

arsenic 975 mg element digestive system

bee sting venom 500 mg biological nervous system

cyanide 250 mg organic causes cell death

aflatoxin 180 mg biological kidney/liver

mamba venom 120 mg biological nervous system

black widow venom 70 mg biological nervous system

formaldehyde 11 mg organic causes cell death

ricin (castor bean) 1.76 mg biological kills cells

VX (nerve gas) 189 mcg organophosphate nervous

tetrodotoxin 25 mcg biological nervous system

mercury 18 mcg element nervous system

botulinum (botulism) 270 ng biological nervous

tetanospasmin (tetanus) 75 ng biological nervous system


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Many poisons, however, are substances meant for human food or medicines:

Some mushrooms are poisonous

Drinking water contaminated by agricultural or industrial chemicals Food that has not been properly prepared or handled

Drugs, helpful in therapeutic doses but deadly when taken in excess

ex. Beta blockers, a class of drugs used to treat heart and other

conditions ( angina, high blood pressure, migraine, headache

prevention etc) in excess, they can cause difficulty in breathing,

coma, and heart failure.

ex. Warfarin (Coumadin): a blood thinner used to prevent blood clots,

is also the active ingredient in many rat poisons and may cause

heavy bleeding and death if too much is taken.

ex. Vitamins: especially A and D, taken in large amounts can cause

liver problems


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ROUTES OF ABSORPTION

How a poison gets into the body

By the route of exposure orthe route of absorption.

Through the mouth by swallowing (ingestion) Small children often swallow poison accidentally adults who want to poison themselves may swallow poison.

pesticide poisoning: people eat, drink or smoke after they have been handlingpoisons, without first washing their hands

When poisons are swallowed they go to the stomach and some of them pass throughthe gut walls and into the blood vessels, provoking poisoning.

To stop poisons passing from the gut into the blood:

Vomiting soon after swallowing a poison , the poison may be expelled from the

body before a poisonous dose gets into the blood. give act ivated charc oal because this binds some poisons so that they cannot

pass through the gut walls

give laxat ivesto make the poison move through the gut and out of the body morequickly.

If poisons do not pass through the gut walls, they cannot affect other parts of the bodyand they move along the gut and leave the body in the faeces


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Through the lungs by breathing (inhalation)

gas, fumes,

vapor, smoke,dust or fine spray droplets

may be breathed into the mouth and nose and go down the air passages into the

lungs and into the blood vessels very quickly because the air passages in the

lungs have thin walls and a good blood supply.

Small particles pass into the lungs. Larger particles are trapped in the mouth, throat and nose

and may be swallowed.

Poisons may be breathed

when spraying pecticides or

when ihhaling fumes from oil or gas heaters, cookers, and fires whenthe smoke cannot get outside or if the room does not have a good

supply of fresh air


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Through the skin by contact with liquids, sprays or mistsThe skin is a barrier that protects the body from poisons but

if the chemical is sprayed or splashed onto the skin, or

if people wear clothes soaked with chemical, poisons can pass through the skin.

Quicker passage of the poison

through warm, wet, sweaty skin than through cold, dry skin,

through skin damaged by scratches or burns than through undamaged skin.

The poison mu st be washedoff the skin before a poisonous dose gets into the body.

By injection through the skin From a syringe,

a pressure gun, during tattooing,

by the bite or sting of a poisonous animal, insect, fish or snake.

Direct ly into th e blo od vessels(quick effect) or

under the sk in into mu sc le or fatty t issues(acts more slowly because it has

has to pass through several layers of tissue before reaching the blood vessels)


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What happens when poison is inside the body

It is carried to the whole body as the blood is pumped round the body by the heart

Some poisons are changed in the body, mostly in the liver, into other chemicals called

metabolites , which are more easily passed out of the body than the original

chemicals.

Unchanged poisons or their metabolites usually leave the body

in the urine : passage of the poison from the blood into urine takesplace in the kidneys

in the faeces : poison may have passed down the gut without beingabsorbed into the blood or it may have been absorbed

into the blood and then passed out into the gut again

in the sweat, or

in the air that a person breathes out : poison from blood intobreathed-out air takes place in the lungs


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THE EFFECTS OF POISONLocal vs Systemic Health Effects

Local effect refers to an adverse health effect that takes place at the point or area

of contact. The site may be skin, mucous membranes, the respiratory tract,gastrointestinal system, eyes, etc.

Absorption does not necessarily occur.

Systemic effect refers to an adverse health effect that takes place at a locationdistant from the body's initial point of contact and presupposes that absorptionhas taken place.

Ex. arsenic effects to the blood, nervous system, liver, kidneys and skin;benzene effects to the bone marrow.

Substances with systemic effects, which are cumulative poisons, often have"target organs" in which they accumulate and exert their toxic effect, which isnot seen until a critical body burden is reached.

Ex. heavy metals such as lead.

When exposure occurs to several substances simultaneously the resultantsystemic toxic effect may be significantly greater in combination than theadditive toxic effect of each substance alone. This is called a synergistic orpotentiating effect

Ex. exposure to alcohol and chlorinated solvents; or smoking and asbestos.


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LOCAL EFFECTSare l imited to the part of the bod y in contact w ith the chemical(the sk in, the eyes, the air passages or th e gut)

It must be washed off straight away

An irritant chemical causes : pain

swelling

itching

watery eyes

irritation of the throat causing coughing

skin rashes

skin burns, like the burns caused by fire, if it is in contact with the skin for a

long time (ex. wearing contaminated clothes for several hours)

A cor ros iveorcaust icchemical very quickly causes painful burns anddestroys the skin ( skin may turn grey-white or brown).


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SYSTEMIC EFFECTSoccur when the amount of a poison absorbed into the body is greater than theamount the body can get rid of, and the poison builds up and reaches the

threshold level.Poisons can :

damage organs such as the brain, nerves, heart, liver, lungs, kidneys, or skin. The most

affected organs are called the target organs.

block messages between nerves.

stop the body working properly, for example, by blocking energy supply or oxygen supply.

On the eyessevere pain if they get into the eyes.

burn the surface of the eye and cause scars or even blindness.

red and watery eyes

bright light will hurt.

Inside the gut the mouth and throat or the inside of the gut may be damaged

Swelling of the throat if is burnt so quickly that he cannot breathe

Vomiting

diarrhoea,

the vomit and faeces may contain blood. belly pain


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Inside the air passages and lungsSome gases and vaporscan irritate the nose, throat and upper air passages and cause

coughing and choking.

the lungs fill with water (lung oedema) very soon after a person breathes in the

substance, or up to 48 hours afterwards.

When people are unconsciousit is very dangerous to try to give them any food, drink or

medicine, becausethe air passage does not close, so there is nothing to stop food, drink or

vomit getting into the lungs and blocking the air passages or causing lung oedema.

At injection sites : into the skinPoisons from insect stings and snake bites may cause pain and swelling where they are

injected, provoking local and maybe systemic effects

Effects on unborn babiesA baby inside the womb can be harmed, most likely during the first three months of pregnancy

when the nervous system and all the major organs begin to form, by some poisonous chemicals

alcohol or smoking during pregnancy

medicines

The parts of the baby usually affected are the bones, eyes, ears, mouth and brain

If the damage is very bad the baby will stop growing and die.


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CONCLUSION :

Before you send a person home always check:

how long ago the exposure to poison happened;

how long it usually takes before the effects of the poison can be seen

check on the person for 12-24 hours to see if any ill effects develop.

In some cases you may need to watch them even longer than that.

Exposure to a chemical does not affect everyone in exactly the same way.

young children and old people are more likely to be severely poisoned thanyoung adults;

people who are not eating well, or are drinking a lot of alcohol or have a

disease, are more likely to be severely poisoned than healthy people

.

Nausea is a sign and vomiting is a symptom of poisoning.

Almost every possible sign or symptom of a poisoning can also be caused bya nonpoison-related medical problem. They can be found in many illnesses

non related to poisoning (stroke, heart attack, stomach ulcers, gallbladder

problems, hepatitis, appendicitis, head injuries, and many others).


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REFERENCES

1. http://www.emedicinehealth.com

2. Management of Poisoning - A Handbook for Health Care Workers(ILO, WHO; 1997 267 pages)

3. http://chemistry.about.com(LIST OF POISONS)

4. Management of poisoning, J. Henry, H. Wiseman, WHO,1997

5. Guidelines for poison control. WHO, 1997

6. Handbook of the acute poisoning - professor A. Monov, Medicine

and physical culture, Sofia, 1987.

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General Information on Poisons and Poisoning. Routes of Absorption, Local Effects, Systemic Effects