POISONING AND TOXICOLOGY DR ABD. HALIM BIN MANSAR

POISONING AND POISONING AND TOXICOLOGYTOXICOLOGY

DR ABD. HALIM BIN MANSAR DR ABD. HALIM BIN MANSAR

POISONING

DefinitionTypes of poisonRoutes of administrationTolerance, Idiosyncracy & Drug interactionPoisoning by common drugs and toxic substancesDoctor’s role in poisoningAlcohol, accidents and the lawPostmortem detection of toxic substances

POISONINGPOISONING

Definition:Definition:

Poison - any substance taken into the Poison - any substance taken into the body that interferes with normal body that interferes with normal physiological functions.physiological functions.

Poisoning - the state produced by Poisoning - the state produced by introduction of a poison into the body.introduction of a poison into the body.

PoisoningPoisoning

Poisoning is very common, most Poisoning is very common, most poisonings being accidental or suicidal in poisonings being accidental or suicidal in nature (homicidal is now rare)nature (homicidal is now rare)

Majority of the accidental group = childrenMajority of the accidental group = children Two main types of poisoning;Two main types of poisoning;

• those in the home from medicinal those in the home from medicinal substances and domestic chemicalssubstances and domestic chemicals

• those in agriculture and industry from a those in agriculture and industry from a wide range of toxic substances.wide range of toxic substances.

PoisoningPoisoning

DefinitionDefinition Types of poisonsTypes of poisons Routes of administrationsRoutes of administrations Tolerance, Idiosyncrasy & Drug InteractionTolerance, Idiosyncrasy & Drug Interaction Poisoning by common drugs and toxic Poisoning by common drugs and toxic

substancessubstances Doctor’s Role in poisoningDoctor’s Role in poisoning Alcohol, accidents and the lawAlcohol, accidents and the law Posmortem detection of toxic substancesPosmortem detection of toxic substances

POISONINGPOISONING

Types of poisonTypes of poison• target organ (liver, kidney, target organ (liver, kidney,

haematopoietic system, etc)haematopoietic system, etc)• use (pesticide, solvent, food additive, use (pesticide, solvent, food additive,

etc.)etc.)• source (animal and plant toxin)source (animal and plant toxin)• effects (cancer, mutation, liver injury, etc)effects (cancer, mutation, liver injury, etc)• chemistry (aromatic amine, halogenated chemistry (aromatic amine, halogenated

hydrocarbon)hydrocarbon)

PoisoningPoisoning

DefinitionDefinition Types of poisonsTypes of poisons Routes of administrationsRoutes of administrations Tolerance, Idiosyncrasy & Drug Tolerance, Idiosyncrasy & Drug

InteractionInteraction Poisoning by common drugs and toxic Poisoning by common drugs and toxic

substancessubstances Doctor’s Role in poisoningDoctor’s Role in poisoning Alcohol, accidents and the lawAlcohol, accidents and the law Posmortem detection of toxic Posmortem detection of toxic

substancessubstances

Routes Of AdministrationsRoutes Of Administrations

Ingestion (gastrointestinal tract)Ingestion (gastrointestinal tract) Inhalation (lungs)Inhalation (lungs) Topical (skin)Topical (skin) parenteral (intravenous)parenteral (intravenous)

Toxic agents elicit greatest effect and Toxic agents elicit greatest effect and produce most rapid response when produce most rapid response when given by the intravenous route.given by the intravenous route.

PoisoningPoisoning





ToleranceTolerance

Definition: a state of decrease Definition: a state of decrease responsiveness to a toxic effect of a responsiveness to a toxic effect of a chemical resulting from prior exposure chemical resulting from prior exposure to that chemical or to a structurally to that chemical or to a structurally related chemical.related chemical.

Example: carbon tetrachloride Example: carbon tetrachloride produces tolerance to itself by produces tolerance to itself by decreasing formation of the reactive decreasing formation of the reactive metabolite that produces liver injury.metabolite that produces liver injury.

IdiosyncrasyIdiosyncrasy Definition: a genetically determined Definition: a genetically determined

abnormal reactivity to a chemical. The abnormal reactivity to a chemical. The response observed is usually similar to response observed is usually similar to that observed in all individuals (may take that observed in all individuals (may take the form of extreme sensitivity to low the form of extreme sensitivity to low doses or extreme insensitivity to high doses or extreme insensitivity to high doses of the chemical).doses of the chemical).

Example: Prolonged muscular relaxation Example: Prolonged muscular relaxation and apnoea after a standard dose of and apnoea after a standard dose of succinylcholine.succinylcholine.

Drug InteractionsDrug Interactions Mechanism of drug interaction: alterations in Mechanism of drug interaction: alterations in

absorption, protein binding and absorption, protein binding and biotransformation or excretion of one or both of biotransformation or excretion of one or both of the interacting drugs.the interacting drugs.

The response may be increased or decreased The response may be increased or decreased because of the toxicological responses at the because of the toxicological responses at the site of action.site of action.

Example: carbon tetrachloride and ethanol are Example: carbon tetrachloride and ethanol are hepatotoxic compounds, but together they hepatotoxic compounds, but together they produce much more liver injury than their produce much more liver injury than their individual effects on the liver.individual effects on the liver.

PoisoningPoisoning





Poisoning by common Poisoning by common drugs and toxic drugs and toxic


ParacetamolParacetamol SalicylatesSalicylates ParaquatParaquat OrganophosphateOrganophosphate Carbon MonoxideCarbon Monoxide

ParacetamolParacetamol

Accidental and suicidal poisoningsAccidental and suicidal poisonings Accidental in childrenAccidental in children Suicidal in adultsSuicidal in adults In overdose can cause acute centrilobular In overdose can cause acute centrilobular

hepatic necrosis which is often fatalhepatic necrosis which is often fatal 24 - 48 hours = palor, nausea and vomiting24 - 48 hours = palor, nausea and vomiting Hepatic failure appears 4 - 6 days after Hepatic failure appears 4 - 6 days after

ingestion.ingestion. Treatment: intravenous N-acetylcysteine.Treatment: intravenous N-acetylcysteine.

SalicylatesSalicylates

Aspirin & methyl salicylate Aspirin & methyl salicylate Mild toxicity: vertigo, tinnitus, nausea Mild toxicity: vertigo, tinnitus, nausea

and vomitingand vomiting Ingestion of greater than 400 mg/kg Ingestion of greater than 400 mg/kg

causes severe vomiting, causes severe vomiting, hyperventilation, confusion, coma, hyperventilation, confusion, coma, convulsions, hyper or hypoglycaemia convulsions, hyper or hypoglycaemia and respiratory alkalosis or metabolic and respiratory alkalosis or metabolic acidosis.acidosis.

ParaquatParaquat Accidental or suicidal ingestionAccidental or suicidal ingestion 1-3 days = intense pain in the mouth and 1-3 days = intense pain in the mouth and

pharynx, with inflammation / ulceration of the pharynx, with inflammation / ulceration of the mucous membrane.mucous membrane.

2-4 days = symptoms of renal and hepatic 2-4 days = symptoms of renal and hepatic failurefailure

3-14 days = paraquat is specifically taken by 3-14 days = paraquat is specifically taken by lung tissue. Intra-alveolar oedema and lung tissue. Intra-alveolar oedema and haemorrhage followed by epithelial proliferation, haemorrhage followed by epithelial proliferation, focal atelactasis and massive alveolar fibrosis.focal atelactasis and massive alveolar fibrosis.

ParaquatParaquat

Treatment:Treatment:• immediate gastric lavageimmediate gastric lavage• Fuller’s earth (300 gm in tha Fuller’s earth (300 gm in tha

stomach)stomach)• forced diuresis (intravenous forced diuresis (intravenous

frusemide)frusemide)

OrganophosphateOrganophosphate

Toxic effects results in build up of Toxic effects results in build up of acetylcholineacetylcholine

Clinical features:Clinical features:• symptoms developed within 12 hourssymptoms developed within 12 hours• headache, blurred vision, tremor, twitching, headache, blurred vision, tremor, twitching,

convulsions and comaconvulsions and coma• urinary incontinence, diarrhoea and vomitingurinary incontinence, diarrhoea and vomiting• excessive salivation, lacrimation and sweatingexcessive salivation, lacrimation and sweating• cough, wheezing and sometimes pulmonary cough, wheezing and sometimes pulmonary

oedemaoedema

OrganophosphateOrganophosphate

Treatment:Treatment:• maintain patient’s airwaymaintain patient’s airway• control convulsionscontrol convulsions• intravenous atropineintravenous atropine• antidote = pralidoximeantidote = pralidoxime

Carbon MonoxideCarbon Monoxide

Commonly suicidal Commonly suicidal CO = 300 times affinity for Hb CO = 300 times affinity for Hb

(replaces oxygen from Hb)(replaces oxygen from Hb) symptoms= headache, nausea, symptoms= headache, nausea,

vomiting, convulsions, coma and death.vomiting, convulsions, coma and death. Suicide : tube leading from exhaust Suicide : tube leading from exhaust

pipe into the car passenger pipe into the car passenger compartment.compartment.

PoisoningPoisoning





The Doctor’s Role In The Doctor’s Role In PoisoningPoisoning

The recognition or suspicion of the fact of poisoningThe recognition or suspicion of the fact of poisoning The early diagnosis, where possible, of the nature The early diagnosis, where possible, of the nature

of the poisonof the poison Emergency primary treatment and admission to Emergency primary treatment and admission to

hospital where necessaryhospital where necessary The identification and retention of residual poison The identification and retention of residual poison

in the house, for transmission to the hospital to in the house, for transmission to the hospital to confirm the nature of the poisonconfirm the nature of the poison

Where death has occurred, full cooperation with the Where death has occurred, full cooperation with the pathologist in providing details of any illness, pathologist in providing details of any illness, psychiatric condition and drugs recently prescribed.psychiatric condition and drugs recently prescribed.


Diagnosis: Diagnosis: • should be considered in patients with should be considered in patients with

coma, convulsions, acute hepatic, coma, convulsions, acute hepatic, renal and bone marrow failure. renal and bone marrow failure.

• Ask patient, relatives and friends Ask patient, relatives and friends about possible poisons.about possible poisons.

• Specimens of blood, urine, vomitus Specimens of blood, urine, vomitus and gastric aspirate should be sent and gastric aspirate should be sent immediately for analysis.immediately for analysis.


Treatment:Treatment: Gastric lavage (avoid following Gastric lavage (avoid following

ingestion of kerosene)ingestion of kerosene) Minimise absorption (activated Minimise absorption (activated

charcoal)charcoal) Enhance renal excretion (forced Enhance renal excretion (forced

diuresis with saline + IV furosemide)diuresis with saline + IV furosemide)


Supportive therapy:Supportive therapy: maintenance of ventilation when CNS is maintenance of ventilation when CNS is

depresseddepressed anticonvulsants in patients with convulsionsanticonvulsants in patients with convulsions cerebral oedema treated with IV corticosteroid cerebral oedema treated with IV corticosteroid

and/or IV hypertonic mannitoland/or IV hypertonic mannitol patients should be evaluated and treated for the patients should be evaluated and treated for the

effects of poisoning e.g. hypovolemia, effects of poisoning e.g. hypovolemia, hypotension, cardiac arrhythmias, pulmonary hypotension, cardiac arrhythmias, pulmonary oedema, hypoxia, acute renal failure,acute oedema, hypoxia, acute renal failure,acute hepatic failure and disturbances of fluid and hepatic failure and disturbances of fluid and electrolytes.electrolytes.

PoisoningPoisoning





Alcohol, accidents and the Alcohol, accidents and the lawlaw

Drunk drivers more prone to RTADrunk drivers more prone to RTA Legal limit Legal limit

• 80 mg alcohol per 100 ml of blood80 mg alcohol per 100 ml of blood• 35 microgram alcohol per 100 ml of 35 microgram alcohol per 100 ml of

breathbreath• 107 mg alcohol per 100 ml urine107 mg alcohol per 100 ml urine• Incoordination, tremor, ataxia, confusion, Incoordination, tremor, ataxia, confusion,

coma and even death can occur at coma and even death can occur at progressively higher blood alcohol levels.progressively higher blood alcohol levels.

PoisoningPoisoning





Postmortem Detection of Postmortem Detection of Toxic SubstancesToxic Substances

HistoryHistory External ExaminationExternal Examination Internal Examination Internal Examination Collection of appropriate specimensCollection of appropriate specimens

• blood, urine, stomach contents, liver blood, urine, stomach contents, liver tissue, lung tissuetissue, lung tissue

Analysis (P.J. Chemistry Lab)Analysis (P.J. Chemistry Lab)

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POISONING AND TOXICOLOGY DR ABD. HALIM BIN MANSAR