FORENSIC TOXICOLOGY

Toxicology

Branch of science that treats of poison, their origin, physical & chemical properties, psychological action, treatment of their noxious effect & methods detection. The etymology of toxicology came from “toxico” that means poison & “ology” that means study of science.

Poison

It is a substance that when introduced into the body & is absorbed through the blood stream & acting chemically is capable of producing noxious effect.

Classification of Poison

1. According to Kingdoma. Animal – ex. Cantharides

b. Vegetable- ex. Strychnine

c. Mineral-ex. Hydrochloric acid

2. According to Chemical Properties

A.Inorganic Poison without carbon a. Volatile-ex. Bromine, chlorine & Iodine

b. Non-volatile-ex. Sulfuric acid

c.Mineral-ex. Hydrochloric acid

d. Mineral alkalis-ex. Sodium hydroxide

B. Organic Poison

a. Volatile-ex. Alcohol, Chloroform

b. Alkaloid-ex. Strychnine

Alkaloids- are nitrogenous organic basic compound with bitter taste containing usually oxygen that occurs especially in seed plantsc. Animal poison-ex. Snake venom

d. Bacterial-ex. Ptomaine

e. Organic poison-ex. Salicylic acid

f. Glucosides-ex. Digitalis

3. According to Physiological ActionA. Corrosives- highly irritant poisons that

cause local destruction of tissues & characterized by nausea, vomiting, great local distress. Eg. Strong acids & alkalis

B. Irritants- one that produces irratition or inflammation of the mucus mebrane & characterized by vomiting, pain in the abdomen & purging. Eg. Arsenic

C. Narcotics- one that produce stupor, complete insebility/loss of feeling. Eg. Opium,Demerol & Coccaine

D. Neurotics- one that act chiefly on the nervous system producing delirium, convulsion & respiration as the outsatanding synptoms. Eg. CO, alcohol, opium & strychnineE. Depresants/Sedatives- agents that depress the physiological action of an organ

F. Tetanics- substances that act upon the spinal column producing such spasmodic & continous contraction of muscles as a result of stiffness of the parts which they are attached

G. Asthenics/Exhaustive- agents that produce exhaustion, marked loss of vital/muscular power. Eg. Hydrocyanic acid

4. According to Pharmalogical ActionA. Substance characterized by local

action-ex. Volatile oils & skin irritants

B. Substances characterized by their action after absorption-ex. Alkaloid

C. Heavy metals & metalloids-ex. Phosphorous, arsenic, & mercury

5. According to methods of IsolationA. Volatile poisons are those isolated

by distillation with or without current steam.

B. non-steam volatile poisons are those isolated by extraction with organic solvents.

C. metallic poisons that are isolated by refluxion.

D. D. substances for which special method of isolation are required.

Two types of Poisoning:

1. From medical point of view

2. From legal point of view

I. From medical point of view

1. Acute poisoning

2. Sub-acute poisoning

3. Chronic poisoning

II. From legal point of view

4. Accidental poisoning

5. Suicidal poisoning

6. Homicidal poisoning

7. Undetermined

Actions of poison

1. Local- the changes or disturbance produced on the part with which the poison come I contact.

2. Remote- the changes or disturbance produced in distant parts away from the site of application.

3. Combined- the effect of the poison is not only localize at the site but also affects remotes organs.

Posology- a branch of science that treats of the form & quantity of medicine to be administeredwithin a certain period.

Kinds of Dose

1.Safe dose2.Toxic or poisonous dose3.Lethal dose4.Minimum dose5.Maximum dose

Symptoms caused by poisoning & disease 1. Vomiting 2. Convulsion3. Coma4. Dilation of pupils5. Contraction of pupils6. General & partial paralysis7. Slow respiration 8. rapid respiration9. Delirium10.Cyaosis

Effects of blood alcohol(ethanol) concentrationStage of intoxication Percent of alcohol

(ethanol) in blood Clinical

manifestation

Stimulation 0.01-0.10 Norma by ordinary observation

Apparent stimulation 0.05-0.20 Dercreased inhibation Emotional instability

IncoordinationSlowing reaction to

stimuli

confusion 0.10-0.30 Disturbance of sensation

Decrease pain senseStaggering gitSlurred speech

Stupor 0.25-0.40 Marked decrease to stimuli

Approaching paralysis

Coma or Death 0.35-0.50 Complete unconsciousnessSubnormal temp.

An aesthesia Impairment

Stertorous breathing