Toxicology

Introduction Introduction

Toxicology is a science dealing with properties, action, Toxicology is a science dealing with properties, action, toxicity, fatal dose, detection, estimation and treatment of toxicity, fatal dose, detection, estimation and treatment of poisons.poisons.

Toxinology refers to toxins produced by living organism Toxinology refers to toxins produced by living organism which are dangerous to man. Like poisonous plant, venom which are dangerous to man. Like poisonous plant, venom of snake, spider, scorpion.of snake, spider, scorpion.

Contd…….Contd…….

Poison is a substance, which if introduced in living Poison is a substance, which if introduced in living body, or brought in contact with any part through, will body, or brought in contact with any part through, will produce ill health or death, by its constitutional or local produce ill health or death, by its constitutional or local effects or both.effects or both.

Some poison are harmless in small quantity but Some poison are harmless in small quantity but produce death if large quantity is used. produce death if large quantity is used.

Classification of poison according to Classification of poison according to symptoms they produces( mode of action)symptoms they produces( mode of action)

A. A. CorrosiveCorrosive:-:-

1.1. Strong acidsStrong acids :- sulphuric acid, nitric acid, :- sulphuric acid, nitric acid, hydrochloric acid, acetic acid, carbolic acid, hydrochloric acid, acetic acid, carbolic acid, oxalic acid, salicylic acid.oxalic acid, salicylic acid.

2.2. Strong alkalisStrong alkalis :- sodium hydroxide or caustic :- sodium hydroxide or caustic soda, potassium hydrochloride, ammonium soda, potassium hydrochloride, ammonium hydrochloride.hydrochloride.

3.3. Metallic saltsMetallic salts :- zinc chloride, potassium :- zinc chloride, potassium cyanide, ferric chloride, chromates of alkalis, cyanide, ferric chloride, chromates of alkalis, bichromates of alkalis , Mercuric chloride etcbichromates of alkalis , Mercuric chloride etc

Contd…..Contd…..

B. B. IrritantsIrritants :- :-

1. 1. InorganicInorganic:-:-

a.a. Non-metallicNon-metallic:- phosphorus, halogen.:- phosphorus, halogen.

b.b. MetallicMetallic:- arsenic, antimony, mercury, :- arsenic, antimony, mercury, copper, lead, zinc, silver. copper, lead, zinc, silver.

2. 2. OrganicOrganic:-:-

a.a. VegetablesVegetables:- castor oil, cotton oil.:- castor oil, cotton oil.

b.b. AnimalsAnimals:- snake venom, insect bites.:- snake venom, insect bites.

c.c. MechanicalMechanical:- glass powdered, diamond dust.:- glass powdered, diamond dust.

C. C. SystemicSystemic:-:-

1. 1. CerebralCerebral:-:-

a.a. CNS depressantsCNS depressants:- alcohols, general :- alcohols, general anesthetics, opioid analgesic, hypnotics, anesthetics, opioid analgesic, hypnotics, sedatives.sedatives.

b.b. CNS stimulantsCNS stimulants:- cyclic antidepressants, :- cyclic antidepressants, amphetamine.amphetamine.

c.c. DeliriantDeliriant:- Dhatura, belladonna, cannabis, :- Dhatura, belladonna, cannabis, cocaine. cocaine.

2. 2. SpinaSpinal:- l:- nux vomica (strychnine), gelsemium.nux vomica (strychnine), gelsemium.

3. 3. PeripheralPeripheral:- :- conium, curare.conium, curare.

Contd…..Contd…..

3. 3. PeripheralPeripheral:- :- conium, curare.conium, curare.

4. 4. CardiovascularCardiovascular:- :- aconite, quinine, aconite, quinine, tobacco , HCN, oleander, nicotine etctobacco , HCN, oleander, nicotine etc

5. Nephrotoxic :5. Nephrotoxic : Oxalic acid, mercury, Oxalic acid, mercury, cantharides.cantharides.

6. Hepatotoxic: 6. Hepatotoxic: Phosphorous, carbon, Phosphorous, carbon, tetrachloride, chloroformtetrachloride, chloroform

Contd……..Contd……..D. D. MiscellaneousMiscellaneous :- :-

1. 1. InsecticidesInsecticides:-:-

a. a. Organ phosphorus compoundsOrgan phosphorus compounds:-:-

i. Alkyl phosphates:- i. Alkyl phosphates:-

Hexaethyl tetra phosphate (HETP),Hexaethyl tetra phosphate (HETP),

Tetraethyl pyrophosphate (TEPP), Tetraethyl pyrophosphate (TEPP),

Octamethyl pyro-phosphoramide (OMPA)Octamethyl pyro-phosphoramide (OMPA)

ii. Aryl phosphates:-ii. Aryl phosphates:- parathion, diazinon. parathion, diazinon.

b. b. Chlorinated hydrocarbonsChlorinated hydrocarbons:- endrine, D.D.T. and :- endrine, D.D.T. and gamaxin.gamaxin.

2. 2. AntihistaminesAntihistamines

3. 3. Food poisonsFood poisons:- :- Cl.Cl. Botulism, Mushroom poisoning.Botulism, Mushroom poisoning.

Route of administration of poisonRoute of administration of poison:-:-1.1. Inhalation in gaseous or vapor form.Inhalation in gaseous or vapor form.

2.2. Injection into blood vessels(IV)Injection into blood vessels(IV)

3.3. Intramuscular, subcutaneous and intradermal injection.Intramuscular, subcutaneous and intradermal injection.

4.4. Application to a wound(Ulcer)Application to a wound(Ulcer)

5.5. Introduction like oral, nasal, rectal, urethral, vaginal.Introduction like oral, nasal, rectal, urethral, vaginal.

Route of elimination of poisonRoute of elimination of poison:-:-1.1. Kidney Kidney

2.2. SkinSkin

3.3. Bile, milk, saliva, mucous and serous secretion.Bile, milk, saliva, mucous and serous secretion.

4.4. Unabsorbed portion by vomit and faeces.Unabsorbed portion by vomit and faeces.

Factors modifying the action of poisonFactors modifying the action of poison

1.Quanity:- 1.Quanity:- Greater the quantity more severe would be Greater the quantity more severe would be symptoms of poison and usually rapid would be fatal.symptoms of poison and usually rapid would be fatal.

2. Form of poison:- 2. Form of poison:- The action of poison is influences by The action of poison is influences by the form in which it is administered.the form in which it is administered.

a.a. Physical state:- Physical state:- gas, liquid or solid.gas, liquid or solid.

b.b. Chemical combination:- Chemical combination:- for e.g. arsenic is not for e.g. arsenic is not poisonous but its salt arsenious oxide is poisonous.poisonous but its salt arsenious oxide is poisonous.

c.c. Mechanical combination:- Mechanical combination:- for e.g. small dose of for e.g. small dose of concentrated mineral acid produces corrosive action concentrated mineral acid produces corrosive action but same dose largely diluted with water is harmless.but same dose largely diluted with water is harmless.

3. Mode of administration:-3. Mode of administration:- The rapidity of action of a The rapidity of action of a poison depends upon the route of administration, rate poison depends upon the route of administration, rate of absorption and the mode in which it is introduce into of absorption and the mode in which it is introduce into the system. The route of administration may be the system. The route of administration may be enumerated as follows in order of rapidity of action:-enumerated as follows in order of rapidity of action:-

a.a. Inhalation Inhalation

b.b. IntravenousIntravenous

c.c. Intramuscular, subcutaneous, intradermal,rectalIntramuscular, subcutaneous, intradermal,rectal

d.d. OralOral

4. Condition of body:-4. Condition of body:-

a.a. Age:Age:

b.b. Habit:- action of certain poison decrease with Habit:- action of certain poison decrease with habituate. An addict can tolerate larger dose than a habituate. An addict can tolerate larger dose than a non addict. Like alcohol, morphine.non addict. Like alcohol, morphine.

Antidotes Antidotes These are the substances which prevent or neutralize or These are the substances which prevent or neutralize or

counteract the action of poison.counteract the action of poison.

Reasons of use of antidotes:-Reasons of use of antidotes:-

1.1. The poison may not be completely removed by gastric The poison may not be completely removed by gastric lavage or the procedure is contraindicated.lavage or the procedure is contraindicated.

2.2. The poison is already absorbed.The poison is already absorbed.

3.3. The poison has been administered other than ingestion.The poison has been administered other than ingestion.

Classification of antidotes:-Classification of antidotes:-

1.1. Mechanical antidotes or physical antidote.Mechanical antidotes or physical antidote.

2.2. Chemical antidotesChemical antidotes

3.3. Physiological or pharmacological antidotesPhysiological or pharmacological antidotes

4.4. Serological antidoteSerological antidote

1. Mechanical antidotes1. Mechanical antidotes:- acts by preventing absorption :- acts by preventing absorption of poisons.of poisons.

a.a. Activated charcoalActivated charcoal

b.b. Demulcents:- egg albumin, fats, oil.Demulcents:- egg albumin, fats, oil.

2. Chemical antidotes2. Chemical antidotes:-they counteract the action of :-they counteract the action of poison by forming harmless compound, when poison by forming harmless compound, when brought in contact with them.brought in contact with them.

a.a. Sodium sulphate for lead poisoningSodium sulphate for lead poisoning

b.b. Copper sulphate for phosphorus poisoning.Copper sulphate for phosphorus poisoning.

c.c. Ferric oxide for arsenic poisoning.Ferric oxide for arsenic poisoning.

d.d. KMNO4 for Opium and OPCKMNO4 for Opium and OPC

33. Physiological antidotes. Physiological antidotes:- these are the agents which :- these are the agents which act on the tissue of the body and produce symptoms act on the tissue of the body and produce symptoms exactly opposite to those caused by poisons. E.g.:exactly opposite to those caused by poisons. E.g.:

a) Atropine, Pralidoxime for OPCa) Atropine, Pralidoxime for OPC

b) Paracetamol poisoning: N-acetyl cystineb) Paracetamol poisoning: N-acetyl cystine

c) Opioids poisoning: Naloxonec) Opioids poisoning: Naloxone

d) Dhatura Poisoning: Neostigmine.d) Dhatura Poisoning: Neostigmine.

e) Strychnine Poisoning: Barbiturates.e) Strychnine Poisoning: Barbiturates.

4.4. Serological antidoteSerological antidote: Anti-snake venom: Anti-snake venom

Universal antidotesUniversal antidotes:- it is an antidotes that is used in :- it is an antidotes that is used in those cases where the nature of the ingested poison in those cases where the nature of the ingested poison in not known.not known.

It has following compositionIt has following composition:-:-Activated powder charcoal or burnt toast---2 parts (absorbent)Activated powder charcoal or burnt toast---2 parts (absorbent)

Magnesium oxide---1 part 9neutralises if poison is acid)Magnesium oxide---1 part 9neutralises if poison is acid)

Tannic acid or strong tea----1 part( precipitates alkalis)Tannic acid or strong tea----1 part( precipitates alkalis)

Stomach wash/gastric lavage by Boas or Ewald’s tubeStomach wash/gastric lavage by Boas or Ewald’s tube

Chelating agentChelating agent:-:-

These are soluble organic compound which fix metallic These are soluble organic compound which fix metallic ions into their molecular form and make them inactivate. ions into their molecular form and make them inactivate. They form chelate with metallic poisons those are freely They form chelate with metallic poisons those are freely available in the circulation and their early excretion from available in the circulation and their early excretion from the body through kidney.e.g.:-the body through kidney.e.g.:-

1.1. EDTA(ethylene diamine tetra acetic acid):-for lead.EDTA(ethylene diamine tetra acetic acid):-for lead.

2.2. Desferrioxamine:-for acute and chronic iron poisoning.Desferrioxamine:-for acute and chronic iron poisoning.

3.3. Bemigride:- barbiturate poisoningBemigride:- barbiturate poisoning

4.4. Nalorphine:- morphine, heroine poisoning.Nalorphine:- morphine, heroine poisoning.

5.5. Penicillamine (Cuprimine): Free metalsPenicillamine (Cuprimine): Free metals

6.6. Dimercaprol: For arsenic, mercury, copper, bismuth, Dimercaprol: For arsenic, mercury, copper, bismuth, gold.gold.

Principle of management of poisoningPrinciple of management of poisoning

The following principle should be followed in case of The following principle should be followed in case of poisoning:-poisoning:-

1. 1. Removal of unabsorbed poison from the bodyRemoval of unabsorbed poison from the body:-:-

a.a. If inhaled:-take pt. to fresh air. Give oxygen and If inhaled:-take pt. to fresh air. Give oxygen and artificial respiration if necessary.artificial respiration if necessary.

b.b. If bitten or injected:- immediately apply tight band If bitten or injected:- immediately apply tight band above the wound. Release in every 10 minutes for 20-above the wound. Release in every 10 minutes for 20-30 second to prevent gangrene.30 second to prevent gangrene.

c. If local application:- it should be washing with water.c. If local application:- it should be washing with water.

d. If ingested:- stomach wash/ gastric lavage within 3 hr.d. If ingested:- stomach wash/ gastric lavage within 3 hr.

2. 2. Administration of antidotesAdministration of antidotes

3. 3. Prevention of absorption into the systemPrevention of absorption into the system:-:- byby

a.a. Renal excretion can be improved by plenty of fluid, diuretics.Renal excretion can be improved by plenty of fluid, diuretics.

b.b. Increasing diaphoresis ( Perspiration) using neostigmine, Increasing diaphoresis ( Perspiration) using neostigmine, pilocarpinepilocarpine

c.c. By dialysis.By dialysis.

d.d. By chelating agentsBy chelating agents

4. 4. Treatment of general symptomsTreatment of general symptoms:-:-

Pain, shock, peripheral circulatory collapse, electrolyte Pain, shock, peripheral circulatory collapse, electrolyte imbalance.imbalance.

Initial Management of the Initial Management of the poisoned patient (ABCD’s)poisoned patient (ABCD’s)

• First, the airway should be cleared of vomitus or any First, the airway should be cleared of vomitus or any other obstruction and an oral airway or endotracheal other obstruction and an oral airway or endotracheal tube inserted if needed.tube inserted if needed.

• Breathing should be assessed by observation and Breathing should be assessed by observation and oximetry and, if in doubt by measuring arterial blood oximetry and, if in doubt by measuring arterial blood gases patients with respiratory insufficiency should be gases patients with respiratory insufficiency should be intubated and mechanically ventilatedintubated and mechanically ventilated

• Circulation should be assessed by continuous Circulation should be assessed by continuous monitoring of pulse rate, blood pressure , urinary monitoring of pulse rate, blood pressure , urinary output. An intravenous line should be placed and output. An intravenous line should be placed and blood drawn fro serum glucose and other routine blood drawn fro serum glucose and other routine determinationsdeterminations

• Dextrose to treat hypoglycemia (0.5gm/kg)Dextrose to treat hypoglycemia (0.5gm/kg)

History & Physical ExamHistory & Physical Exam

Lab and Imaging procedures:Lab and Imaging procedures: Arterial Blood GasesArterial Blood Gases Electrolytes: Sodium, Potassium, Chloride, Electrolytes: Sodium, Potassium, Chloride,

BicarbonateBicarbonate Renal Function Tests: Blood Urea, Renal Function Tests: Blood Urea,

CreatinineCreatinine ElectrocardiogramElectrocardiogram

DecontaminationDecontamination

Decontamination procedure should be Decontamination procedure should be undertaken simultaneously with initial undertaken simultaneously with initial stabilization, diagnostic assessment and stabilization, diagnostic assessment and lab evaluationlab evaluation

Decontamination involves removing Decontamination involves removing toxins from the skin or GITtoxins from the skin or GIT

A) SkinA) Skin

Contaminated clothing should be Contaminated clothing should be completely removed and double bagged completely removed and double bagged to prevent illness in health care providers to prevent illness in health care providers and for possible lab analysisand for possible lab analysis

Wash contaminated skin with soap and Wash contaminated skin with soap and waterwater

B) GITB) GIT

1.1. Emesis: Emptying of stomach in conscious childrenEmesis: Emptying of stomach in conscious children– Syrup: Ipecac (6-12 months 10 ml single dose and >1 Syrup: Ipecac (6-12 months 10 ml single dose and >1

yr 15 ml) *repeated in 20 mins for those more than 1 yr.yr 15 ml) *repeated in 20 mins for those more than 1 yr.2.2. Gastric Lavage:Gastric Lavage:

– 0.9% saline , Left Lateral position0.9% saline , Left Lateral position3.3. Activated CharcoalActivated Charcoal4.4. Catharsis: Laxative and purgatives Catharsis: Laxative and purgatives

– Mannitol (1-2 gm/kg)Mannitol (1-2 gm/kg)– Magnesium or sodium sulfate (200-300 mg/kg)Magnesium or sodium sulfate (200-300 mg/kg)

* Specific Antidotes** Specific Antidotes*

CONTRAINDICATION OF GASTRIC CONTRAINDICATION OF GASTRIC LAVAGE:LAVAGE:

1.1. Very old patients with esophageal Very old patients with esophageal varices.varices.

2.2. Poisoning with corrosives: danger of Poisoning with corrosives: danger of perforation of stomach.perforation of stomach.

3.3. Convulsant poisons: attempt of using Convulsant poisons: attempt of using tube may lead to convulsionstube may lead to convulsions

4.4. Comatosed patients : risk for aspirationComatosed patients : risk for aspiration

CONTRAINDICATION OF CONTRAINDICATION OF EMESISEMESIS

Corrosives and volatile poisons.Corrosives and volatile poisons. Comatose patients.Comatose patients. Heart disease patients.Heart disease patients. Pregnant women.Pregnant women. Kerosene : may cause aspiration Kerosene : may cause aspiration

pneumonia.pneumonia.