Toxicology Dr. Miada Mahmoud Rady. Introduction A poison : is a substance that is toxic by nature,...

Toxicology

Dr. Miada Mahmoud Rady

Introduction

A poison : is a substance that is toxic by nature, no

matter how it gets into the body or how much is taken.

A drug : is a substance that has some therapeutic effect

when given in the appropriate circumstances and in the

appropriate dose.

An “overdose” : occurs when a drug is taken in excess.

Methods of poisoning

• Poison gain an access to human body via the

following routes:

1. Ingestion .

2. Inhalation .

3. Injection

4. Absorption

Poisoning by ingestion

popular way for suicide

May produce immediate damage or delayed effects

Generally provides time for identification and treatment

Little absorption occurs in the stomach, and the

substance may stay there for a while.

Management aims to remove or neutralize the poison

before it gains access to the intestines.

Poisoning by inhalation

occur when the toxic agent is present in the

surrounding environment

Patient will continue to inhale the toxin as long as

he/she remains in the environment.

Paramedics will also inhale the toxin if not wearing

the proper protective breathing apparatus.

Likely to find more than one patient

Window of opportunity for problem

identification and treatment is limited.

First general management consideration is

scene safety

Poisoning by injection

Usually gain access as the result of :

1. Stings or bites from insects and animals

2. Abuse of intravenously administered drugs

Injected poisons produce either systemic or localized

reactions.

Physical findings will provide clues.

Surface Absorption

Entry through skin or

mucous membranes

Contact with poisonous

plants

Pesticides e.g.

organophosphates

Toxidromes

Toxic syndrome or toxidrome: A group of signs and

symptoms consistently associated with a particular toxin.

Useful for remembering the assessment and management

of different substances in the same group.

Diagnosis can be developed by looking at:

a. History

b. Physical signs

Six major Toxidromes exist:

a. Stimulants

b. Narcotics

c. Cholinergics

d. Anticholinergics

e. Sympathomimetics

f. Sedative/hypnotics

Toxidromes

Patient Assessment

• Toxicologic emergencies are generally

considered medical emergencies.

• General assessment approach is the same

for all patients.

Scene Size-Up

• Patients who have taken an overdose may

be dangerous.

• Call for law enforcement or a crisis unit if

necessary.

Primary Assessment

1. Form a general impression.

2. Identify concerns or life threats.

3. Identify MOI or NOI.

4. Identify need for additional resources.

5. Set the priority.

History Taking

• Use OPQRST and SAMPLE history and obtain the

following:

1. What is the agent?

2. When was poison taken?

3. How much was taken?

4. Has the patient vomited or aspirated?

5. Why was the substance taken?

Emergency Medical Care of toxicological case

1. Ensure scene safety.

2. Maintain the airway and ensure that breathing is

adequate.

3. Ensure that circulation is not compromised and establish

vascular access.

4. Be prepared to manage shock, coma, seizures, and

dysrhythmias.

5. Transport the patient as soon as possible

Emergency room presentation of alcoholism

1. Withdrawal syndrome.

2. Withdrawal seizers

3. Acute alcohol intoxication .

4. Chronic complication of alcoholism.

5. Delirium tremens .

Withdrawal syndrome

• Minor

(1) Restlessness

(2) Anxiety

(3) Sleeping

problems

(4) Agitation

(5) Tremors

• Major

(1) Increased blood

pressure

(2) Vomiting

(3) Hallucinations

(4) Delirium tremens

Withdrawal seizers

1. Occurs as result of abrupt discontinuation after

prolonged use

2. Usually occur within 12 to 48 hours of last drink

3. Use the same care described for alcohol

intoxication.

4. Consult with medical control about administering

benzodiazepines.

Chronic medical problem

1. Chronic malnutrition .

2. Deterioration in higher mental functions

3. Peripheral Neuropathy

4. Gastritis, GERD and GIT bleeding

5. Increased risk of cancer of the mouth and esophagus

6. liver damage , failure and finally cancer.

Acute alcohol intoxication

Due to relatively rapid consumption of alcohol .

Major complication : death from :

1. Respiratory center depression

2. Aspiration of vomitus or stomach contents.

Management of acute alcohol intoxication

1. Establish and maintain the airway: ( A)

a. With an intact gag reflex, place the patient in the

recovery position and be prepared to suction.

b. With no gag reflex, intubate.

2. Give high concentration oxygen and assist ventilations

as necessary. ( B)

3. Establish vascular access. ( C)

4. Monitor ECG rhythm . ( C)

5. Assess blood glucose level. ( C)

6. Administer thiamine 100 mg via slow IV push if

directed to do so by medical control. ( MEDICATION )

7. Transport to an appropriate facility. ( TRANSPORT )

Delirium tremens

1. Start 48 to 82 hours after the last alcohol intake.

2. Signs and symptoms include:

a. Confusion and hallucinations.

b. Tremors and restlessness.

c. Fever and sweating .

d. Hypotension (often due to dehydration).

3. Complication : mortality rate is 15%.

Management

Treatment is aimed at protecting the patient from injury

and supporting the cardiovascular system.

1. Try to keep the patient calm.

2. Administer supplemental oxygen by nasal cannula.

3. Establish vascular access and manage hypotension

with an infusion of normal saline.

4. Check breath sounds during reassessment.

2. Stimulant

Stimulants

Stimulant addiction is characterized by :

1. Users may become addicted within just a few

days.

2. Success of overcoming addiction is low.

3. Increasing paranoia makes encounters risky So

stay alert for signs of violence.

• Examples of stimulants :

a. Caffeine

b. Nicotine

c. Cocaine

d. Amphetamines

Clinical presentation of stimulant substances

Usual dose effects includes:

1. Excitement

2. Delirium

3. Tachycardia

4. Hypertension

5. Dilated pupils

• Toxic ( over dose ) presentation :

1. Psychosis

2. Hyperpyrexia

3. Tremors

4. Seizures

5. Cardiac arrest

Cocaine

•Rapidly absorbed across mucosal membranes, allowing it to be

applied:

1. Topical

2. Insufflated (snorted)

3. Swallowed

4. Injected intravenous

Pathophysiology

• Action : local anesthetic and a CNS stimulant.

• Crack cocaine: Cocaine mixed with baking soda and water

that is cooked or baked.

• Effects are felt between 8 seconds to 1 minute.

• When the effects wear off, the user experiences a “crash”

which to be avoided the patient take more cocaine or

sedatives

COMPLICATION OF COCAINE

1. Lethal ECG dysrhythmias and acute myocardial

infarction

2. Seizures and stroke.

3. Apnea , pneumothorax and pneumomediastinum

4. Hyperthermia.

Amphetamine, methamphetamine, and amphetamine-like drugs

Have a number of legitimate clinical applications

1. Nasal decongestants

2. Diet pills

3. Drugs attention-deficit disorder (ADD).

Management of stimulant abuse

1. Address ABCS :

a. Maintain patent airway

b. Give high flow oxygen

c. Apply ECG monitor , pulse oximeter

d. Establish I.V access and treat shock with normal

saline

e. Apply ice packs for hyperthermia

2. Drugs :

a. Administer benzodiazepines for convulsions

b. Administer nitroprusside for hypertension

c. Administer haloperidol for violent behavior.

3. Transport to appropriate facility : contain dialysis

unit.

Marijuana and cannabis compounds

Derived from Cannabis sativa.

Clinical uses:

1. Treatment of glaucoma.

2. Relief of nausea and appetite loss from

chemotherapy.

Usually smoked, but can be ingested.

Clinical presentation

1. Distorted sense of time and space.

2. Drowsiness and Decreased short-term memory.

3. Diminished motor coordination

4. Increased appetite.

5. Bloodshot eyes.

6. Bronchodilation and tachycardia.

Hallucinogens

Substance that causes some distortion of sense

perception an effect that is termed “psychedelic effects”

LSD (Lysergic acid diethylamine )

Primarily affects the senses

Physiologic effects may include:

1. Mild tachycardia

2. Mild hypertension

3. Dilated pupils

Assessment and management

1. Treatment is primarily supportive.

2. Limit sensory stimulation as much as possible

Phencyclidine (PCP)

1. Typically smoked or snorted (can be injected)

2. Small doses can produce symptoms of intoxication.

3. Manifestation:

a. Mind-body separation

b. Hallucinations

c. Violent outbreaks

Phencyclidine (PCP)

• Assessment and management

1. Try to calm the patient, and address wounds.

2. Administer high-flow oxygen.

3. Monitor vital signs.

4. Provide safe transport.

Sedative and Hypnotics

• Sedative: drugs used to reduce anxiety and

calm agitated behaviors.

• Hypnotic: drugs used as sleeping inducers

• → All Function as CNS depressants

Barbiturates

1. Four basic configurations:• Long-acting• Intermediate-acting• Short-acting• Ultra-short-acting

2. Medical uses :a history of use as sleep aids, anti-anxiety

drugs, and seizure control medications

Manifestation

Mild to moderate barbiturate intoxication :

1. Drowsiness and confusion

2. Decreased inhibitions

3. Ataxia and staggering gait

Sever intoxication :

1. Lethargy and progressive decrease level of

responsiveness

Barbiturates

Management :

1. Withdrawal syndrome will occur in 24 hours.

2. Address ABCS

3. Monitor cardiac rhythm and attach pulse oximetry

4. Treat shock with crystalloids , if no response give

Vasopressors

5. Transport rapidly

Benzodiazepines

• Action : Stimulate the gamma-aminobutyric acid

pathways, resulting in:

1. Sedation

2. Reduced anxiety

3. Relaxation of striated muscle

Benzodiazepines

• Assessment

1. Clinical presentation :

A. Altered mental status

B. Drowsiness

C. Slurred speech

D. General incoordination

Benzodiazepines

• Management

1. Assess and manage the airway.

2. Administer high-concentration oxygen.

3. Establish vascular access.

4. Apply ECG monitor, pulse oximeter, and capnometer.

5. Consider administering flumazenil ( antidote ).

6. Transport to appropriate facility.

Narcotics, Opiates, and Opioids

Narcotic: drug that produces sleep or altered mental status

Opiate: natural drugs derived from opium

Opioid: non-opium-derived synthetics

Assessment

A. Clinical presentation :

Produce a dreamlike state , classic presentation features:

1. Euphoria

2. Hypotension

3. Respiratory depression

4. Pinpoint pupils

Assessment

B. Management

1. Establish a patent airway and vascular access

2. Administer naloxone ( antidote ).

3. Failure of naloxone to reverse symptoms indicate :

• Intake of a potent synthetic drug.

• Intake of multiple drugs.

Cardiac Medications

Definition : drugs used to alter the function or rhythm of the heart.

They include :

a) Antidysrhythmics

b) Beta blockers

c) Calcium channel blockers.

d) Cardiac glycosides.

e) Antigiotensin-converting enzyme inhibitors.

Assessment


1. Hypotension

2. Weakness

3. Rhythm disturbances

4. Difficulty breathing

Assessment

B. Management :

1. Ensure a patent airway and adequate ventilation.

2. Administer high-flow supplemental oxygen.


4. Maintain contact with medical control.

Organophosphates

A major component in many insecticides :

They include : Diazinon , Malathion , Carbamates , Warfarins

and Pyrethrums

Exert their effects at junctions of the nerve cells of the autonomic

nervous system

Very common in agricultural setting

Assessment


1. usually present within the first 8 hours.

2. SLUDGE is helpful in diagnosis.

( Salivation , Lacrimation , Urination , Diarrhea , Gastrointestinal

upset and Emesis ).

Assessment

B. Management :

1. Aggressive Decontamination before initiating care.

2. Establish and maintain the airway.

3. Give high flow oxygen

4. Apply the ECG monitor, pulse oximetry, and capnometer.

5. Use antidote kit or administer atropine IV push pralidoxime

infused with normal saline especially with seizers.

6. Immediately transport.

Carbon Monoxide

• Colorless, odorless, tasteless gas .

• Displaces oxygen, preventing oxygen delivery to tissues causing

Suffocation at the cellular level.

Assessment


Headache , dizziness , nausea ,breathlessness and collapse .

Physical examination may reveal:

1. Bounding pulses

2. Dilated pupils

3. Pallor or cyanosis

4. Cherry red color of the skin

B. Management

1. Remove the patient from the environment.

2. Provide the highest concentration of oxygen.


4. Keep the patient quiet and at rest.

5. Monitor the ECG rhythm and level of consciousness.

6. Transport to the appropriate facility

Chlorine Gas

A. Clinical presentation

1. Minor exposure may lead to : burning sensation in eyes, nose, and

throat and slight cough

2. Severe exposure may lead to : Cyanosis , Shock and Seizures

3. Management

– Remove all patients from the area and triage.

– Deliver high-concentration humidified oxygen.

– Irrigate burning or itching eyes and skin.

Cyanide poisoning assessment

A. Clinical presentation:

1. Palpitations

2. Odor of almonds on the breath

3. Rapid respirations and pulses

4. Bright red venous blood and body

5. Finally gradual loss of consciousness

Assessment

B. Management :

Should be treated as fast as possible.

If cyanide was inhaled:

1. Remove the patient from the source.

2. Establish an airway.

3. Administer 100% supplemental oxygen.

4. Assist ventilations as needed.

Cyanide

5. Use the cyanide antidote kit. ( amyl nitrate , sodium

nitrate and sodium thiosulphate.)

6. If unavailable :

Break amyl nitrite into gauze pad

Hold over the patient’s nose for about 20 seconds

Allow the patient to breathe a high concentration of oxygen for

about 40 seconds.

Other antidotes

• Hydroxocobalamin

1. A safe alternative or adjunct to traditional treatment

2. Included in the “Cyanokit”

3. Complication : Allergy/anaphylaxis .

• Methylene blue

1. An antidote used to treat methemoglobinemia

2. Administered under the guidance of an expert

Caustics ( strong acids and alkalis)

Assessment and management :

1. For caustic ingestion:

a. Give milk and establish vascular access.

b. DO NOT Give any “neutralizing substances.”

c. DO NOT Induce vomiting or perform gastric lavage.

d. DO NOT Give activated charcoal.

e. Immediate transport is indicated.

Caustics assessment and management

2. For eye exposure:

1. Place the prong section of a nasal cannula on the bridge of the

patient’s nose.

2. Plug in a macro IV administration set, and provide continuous

irrigation.

3. For dermal exposure:

1. Dilute and flush away substance.

Drugs Used to Facilitate Sexual Assault

1. GHB (Gamma-hydroxybutyrate)

Odorless , colorless liquid, with a salty taste that produce

hypnosis

Exerts its effects within 30 to 60 minutes.

Management :


2. Assist breathing and administer oxygen.

3. Establish vascular access

4. Monitor LOC.

5. Provide rapid transport

Drugs Used to Facilitate Sexual Assault

1. Rohypnol (roofies)

1. Potent benzodiazepine

2. Illegal to make or distribute

Methyl Alcohol

• Pathophysiology– Formaldehyde and formic acid are responsible for

methanol poisoning.– Peak blood levels attained within 30 to 90 minutes.

Assessment

A. Clinical presentation :– Symptoms appear 12–18 hours after ingestion:

• Headache or vertigo• Abdominal pain , Nausea and vomiting• Blurred vision or blindness

– Physical exam findings may include:• Altered mental status• Dilated pupils with sluggish or no reaction• Tachypnea• Hypotension

Assessment

B. Management

1. Establish the airway and vascular access.

2. Assess blood glucose level.

3. Consider sodium bicarbonate.

4. Provide immediate transport.

5. Activated charcoal is contraindicated.

Ethylene Glycol

A. Clinical presentation : passes in 3 stages – Stage 1:

• CNS depression , seizers and coma • Intoxicated appearance• Nausea, vomiting

– Stage 2: • Tachypnea , tachycardia and hypertension • CHF

– Stage 3: • Renal damage

Ethylene Glycol

B. Management

1. Care is the same as for methanol poisoning.

2. May be ordered to administer calcium gluconate

Hydrocarbons

Hydrocarbons

1. Hydrocarbon inhalation :

a. Remove from the noxious environment.

b. Administer high-concentration oxygen.

c. Promptly transport to the appropriate facility.

Hydrocarbons

2. Hydrocarbon ingestion :

Clinical presentation :

a. Aspiration pneumonia .

b. Low viscosity facilitates the uptake of a hydrocarbon by

tissues of the CNS CNS affection .

c. Gastric irritation .

Hydrocarbons

Management :

1. All symptomatic patients should be transported.

2. Decontaminate the patient.

3. Establish and maintain airway and ventilation.


5. Continuously monitor the ECG rhythm.

6. Administer sequential infusions of normal saline.

Hydrofluoric Acid/Hydrogen Fluoride

• Pathophysiology

Toxicity from an extremely small amount

Leaches calcium and magnesium from body :

1. Profound hypocalcemia and hypomagnesemia.

2. A massive release of sequestered potassium.


1. Inhalation causes:

a. Bronchospasm

b. Local airway injury

c. Wheezes, rhonchi

d. Pneumonitis or

pulmonary edema

2. Ingestion causes:

a. Vomiting

b. Abdominal pain

c. Gastritis

d. Profound systemic

toxicity


Management :

1. Manage the ABCs.

2. For ingestion, provide stomach evacuation.

3. Administer a calcium- or magnesium-containing substance.

Hydrogen sulphide

1. Very high exposure :

a. Seizures

b. Shock

c. Coma

d. Cardiopulmonary arrest

1. Low-level exposure :

a. Eye, nose, and throat irritation

b. Headache

c. Bronchitis

Rotten egg odor

Hydrogen Sulfide

• Management:

1. No proven antidote.

2. Remove patient from the contaminated area.

3. Management is largely supportive.

Oxides of Nitrogen

• Clinical presentation :

1. Irritation of the throat and upper respiratory tract

2. Buildup of fluid in the lungs ( pulmonary edema )

3. Difficulty breathing • Management

1. Remove patient from environment.

2. Provide supportive care.

3. Gain IV access.

4. Be prepared to intubate.

Tricyclic Antidepressants

Clinical presentation:

1. Altered mental status

2. Dysrhythmias

3. Dilated pupils

4. Urinary retention

5. QT prolongation on ECG

The most common drug causing toxicity

Tricyclic Antidepressants

1. Maintain the airway and administer high-flow

supplemental oxygen.

2. Establish vascular access and assess blood glucose

level.

3. Provide continuous ECG monitoring

Management

4. Consider activated charcoal and sodium

bicarbonate.

5. Manage hypotension with normal saline.

6. Seizures: benzodiazepines and prepare for

intubation.


Monoamine oxidase inhibitors

• Used on treatment of atypical depression.

• Easily cause toxicity due to :

1. Major potential for drug interactions.

2. Tight therapeutic window.

• Symptoms appear 6–12 hours or more following ingestion.

• Prepare to manage a life-threatening event


Early Moderate toxicity Sever toxicity

HyperactivityDysrhythmiasHyperventilationNystagmus

Chest painPalpitationsHypertensionDiaphoresisAgitated behaviorMarked hyperthermiaHallucinations

BradycardiaHypotensionSeizuresWorsening hyperthermiaPulmonary edemaComaCardiac arrest

Management




level.


Management


bicarbonate.



intubation.


Selective Serotonin Reuptake Inhibitors

• Clinical presentation : 50% of patients may be asymptomatic. Most common symptoms are:

1. Nausea, vomiting

2. Dysrhythmias

3. Sedation

4. Tremors

Management




level.


Management


bicarbonate.



intubation.


Serotonin syndrome

Definition : reaction that occur with drugs that increase central serotonin

neurotransmission

Presentation :

1. Difficult to diagnosis and fatal

2. Lower muscle rigidity is one of the few classic signs.

3. Confusion or disorientation and agitation

Primary treatment is discontinuation of the therapy

Field treatment is mainly supportive

Lithium

• Used in treatment of bipolar disorders.


Early late

Nausea

Vomiting

Hand tremors

Excessive thirst

Slurred speech

Ataxia

Muscle weakness

Incoordination

Blurred vision

Hyperreflexia

Management




level.


4. Treat hypotension with serial normal saline boluses.

5. Rapid transport.

Non prescription analgesics ( over the counter analgesics)

1. Non steroidal anti-inflammatory drugs.

2. Salicylates ( aspirin)

3. Acetaminophen .

Non steroidal anti-inflammatory

Long term complication is more common than acute toxicity

and include :

1. Renal dysfunction and renal failure.

2. Gastritis and gastrointestinal bleeding.

Acute ingestion and overdoses are rare and mostly suicidal.

Clinical presentation of acute toxicity

1. Nausea , vomiting and abdominal pain .

2. Headache , seizures and altered mental status.

3. Bradycardia and hypotension.

4. Aseptic meningitis ( meningism ) : characterized by neck

stiffness , headache and fever.

5. Some patient may be asymptomatic.

Management

1. Establish and maintain the airway and administer high

concentration supplemental oxygen.


3. Administer boluses of normal saline for hypotension.

4. If hypotension persists, consider giving a Vasopressors.

5. Treat seizures with benzodiazepines .

6. Transport to appropriate facility

Salicylates poisoning

Examples : aspirin and liniments used with hot-air vaporizers .

Clinical presentation depend on :

1. Patient’s age.

2. Dose ingested.

3. Duration of exposure.


Mild toxicity Moderate toxicity Sever toxicity

Nausea.

Vomiting.

Abdominal pain.

Vomiting

Sweating

Hyperpnoea

Ringing in the ears

Pulmonary edema

Combined

respiratory

alkalosis and

metabolic acidosis.

Overdose in children is usually accidental while in adults its

usually intentional .

Indicator of poor prognosis :

1. High fever

2. Seizures

3. Cardiac dysrhythmias

MANGEMENT

1. No antidote is available.

2. Maintain the airway and provide high concentration oxygen.

3. Establish vascular access and administer normal saline for

hypotension.

4. Monitor signs of respiratory fatigue and carbon dioxide levels

with capnometer.

5. Transport to an appropriate facility

Acetaminophen

Well-tolerated with few side effects

Toxicity comes from two sources:

1. Taking too much due to common belief that it is not dangerous

2. Lack of awareness that it is an ingredient in many other

preparations.

Signs and symptoms occur in four distinct stages.

Hepatotoxic

Management

1. Try to accurately estimate the time of ingestion

2. Maintain the airway and administer high concentration

oxygen.


4. For recent ingestions, administer activated charcoal

5. Transport to an appropriate facility

6. Acetaminophen antidote is acetylcystiene ( should be given

within the first 8 hours.

Theophylline

• Bronchodilator used for treatment of B.A and COPD.

• Toxic even in therapeutic doses , as it usually causes cardiac

arrhythmias e.g. Atrial tachycardia , atrial fibrillation , atrial

flutter , premature ventricular contraction and ventricular

tachycardia.

• Very narrow therapeutic range.


1. Gastrointestinal upset in mild toxicity

2. CNS stimulation : restlessness , insomnia , irritability ,

agitation and seizures

3. Cardiac arrhythmia which may be fatal.

Management

1. Maintain the airways and administer high-flow oxygen.


3. Continuously monitor ECG rhythm.

4. Administer activated charcoal after consulting medical control.

5. Administer fluid boluses for hypotension

6. Treat dysrhythmias per ACLS

7. Rapid transport

Iron

Present in many multivitamin preparation.

Ingestion of a large dose places children at risk of dying unless

aggressive and timely interventions take place.


GI toxicity symptoms:

(1) Abdominal pain

(2) Vomiting

(3) Diarrhea

Systemic toxicity symptoms:

(1) Hypotension

(2) Shock

(3) Metabolic acidosis

(4) Tachypnea

Management

1. Address ABCS.

2. Rapid transport.

Food poisoning

When you encounter two or more people sick at the same time and

at the same scene with similar symptoms, think food poisoning

or CO poisoning.


1. Should be suspected when more than one person at same

scene and sharing same food or eating at same place present

with the same symptoms.

2. Usually gastrointestinal symptoms ( diarrhea , vomiting ).

3. Hypotension may occur from fluid loss and electrolyte

imbalance.

Management


2. Administer high-flow supplemental oxygen.

3. Establish vascular access and watch for signs of shock.

4. Administer fluid boluses of normal saline for hypotension.

5. Consider administration of Diphenhydramine per local protocol

6. Transport to an appropriate facility.

Thank you

Toxicology Dr. Miada Mahmoud Rady. Introduction A poison : is a substance that is toxic by nature,...

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Transcript of Toxicology Dr. Miada Mahmoud Rady. Introduction A poison : is a substance that is toxic by nature,...