poisoning

Poisoning & Its Management

1.

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Poisoning & its

Management

by

Md. Monirul Islam

Pharmacy Discipline

Khulna University

Bangladesh


2. Introduction

With the availability of a vast number of chemicals and

drugs, poisoning is a common medical emergency in any

country. The reasons for toxic exposures are as wide and

varied from recreational use to abuse of medications to

accidental home or occupational exposures, deliberate

self harm and environmental pollution. The clinical

spectrum of poisoning hence include acute, acute in

chronic and chronic intoxications. The clinical guidelines

are limited to acute poisonings of common toxins in the

context to maintain focus on the principles of emergency

management of poisoning. Fig: Poisons

3. Poison

A poison is any substance that is harmful to the body. There are many different types of

poison. Many poisonous substances are products people have around the house. Even

medicines that aren't taken as directed can be harmful.

“What is it that is not a poison? All things are poison and nothing is without poison. Solely,

the dose determines that a thing is not a poison.” Paracelsus (1493–1541), the Renaissance

Father of Toxicology, in his Third Defense”.

4. Poisoning

Poisoning occurs when any substance interferes with

normal body functions after it is swallowed, inhaled,

injected, or absorbed. Poisonings are a common

occurrence.

In 80% of the cases, the victim is a child under the

age of five. Curiosity, inability to read warning labels,

a desire to imitate adults, and inadequate

supervision lead to childhood poisonings. Fig: Route of poisoning

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The elderly are the second most likely group to be poisoned. Mental confusion, poor

eyesight, and the use of multiple drugs are the leading reasons why this group has a high

rate of accidental poisoning. A substantial number of poisonings also occur as suicide

attempts or drug overdoses.

5. Types of poisoning

1. Deliberate:

o Overdose as self-harm or suicide attempt.

o Child abuse

o Third party (attempted homicide, terrorist, warfare).

2. Accidental:

o Most episodes of paediatric poisoning.

o Dosage error:

Iatrogenic

Patient error

o Recreational use.

3. Environmental:

o Plants

o Food

o Venomous stings/bites

4. Industrial exposures.

5. Poisoning Causes

Substances that may act as poisons include the following:

Cleaning products

Household products, such as nail polish remover and other personal care products

Paint thinner

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Fig: Different types of poisons

Pesticides used in the house or in the yard

Chemicals used in the yard, such as herbicides, fertilizers and fungicides

Metals, such as lead

Mercury, which can be found in old thermometers and batteries

Prescription and over-the-counter drugs when combined or taken the wrong way

Illegal drugs

Carbon monoxide gas

Contaminated food

Plants, such as poison ivy and poison oak

Venom from certain snakes and insects

6. Symptoms of poisoning

The effects of poisoning depend on what substance patients are exposed to, and the type

and amount of exposure. Poisoning can cause short-term effects, like a skin rash or

vomiting. In serious cases, it can cause brain damage, coma or death.

The following are some possible symptoms of poisoning:

Vomiting

Diarrhea

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Nausea

Redness or sores around the mouth

Drooling or dry mouth

Dilated pupils (pupils that are bigger than

normal) or constricted pupils (pupils that are

smaller than normal)

Rash

Confusion

Shaking or seizures

Trouble breathing Fig: Symptoms of poisoning

Unconsciousness (fainting)

7. Concerns about poisoning

When managing patients with toxic exposures there are several concerns that the physician

is faced with including the following:

• Is the substance toxic? How toxic is it?

• Was there a toxic exposure?

• How can I manage the patient?

– Home with advice.

– Observe and Discharge.

– Admit.

8. Management of poisonings

The holistic management of toxic exposures should include the following considerations

based on a risk assessment approach:

I. Resuscitation and stabilization

II. Toxic Diagnosis

III. Therapeutic interventions

Decontamination

Enhanced elimination of absorbed toxins

Antidotes

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IV. Supportive care

8.1. Resuscitation and stabilization

On arrival of a patient with poisoning, the initial priorities are the maintenance of airway,

breathing and circulation. If the patient has an altered level of consciousness, his cervical

spine must be immobilized till an injury can be ruled out. If respiratory inadequacy is

present, endotracheal intubation is required.

Hypotension in poisoned patients is most often due to loss of fluids or toxin induced

vasodilatation. Hence, crystalloids are the first choice of treatment of hypotension. Before

infusing fluids, blood should be withdrawn for investigations (including sugar, urea,

electrolytes and acid-base status). Rectal temperature should be obtained in all patients

with altered sensorium.

After initial resuscitation, all patients with altered sensorium should receive a ‘cocktail’ of

50% dextrose, naloxone and thiamine. At present, it is recommended to check the blood

sugar using a reliable bedside test and to administer dextrose only if the blood sugar is

below 80 mg/dl. However, if the sticks are not available, it is still advisable to administer

dextrose to all patients with altered sensorium, including those with focal neurologic

deficits.

Another component of the ‘cocktail’ recommended in patients with altered mental status is

naloxone. It is able to rapidly counteract the sedation and respiratory depression induced by

opiates. The dose is 2 mg in all age groups. However, if the patient is an opioid addict and is

not apnoeic, the initial dose may be reduced to avoid withdrawal features.

8.2. Toxicological diagnosis

Several considerations are needed in making a toxicological diagnosis and in some instances

this may be challenging with the lack of information from the patient either due to

deliberate concealment and genuine lack of appreciation or awareness of the situation or

secondary to altered mental states of the victim.

Establishing the specific toxin or toxins responsible for the poisoning is crucial to the

management of final outcome. If attempts to obtain the specific agent are in vain the

physician could perform a careful examination to look for a toxidrome which are a

constellation of signs and symptoms that point towards establishing a particular class of

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toxins that is likely contributing to the patients’ presentation. Some examples of toxidromes

are given below-

Signs & Symptoms

- Salivation

- Lacrimation

- Urinary incontinence

- Defaecation

- Gastric cramping, hypermotility

- Emesis

Possible toxins

- Organophosphate compounds

- Carbamate insecticides

Sympathomimetic toxidrome

Signs & symptoms

- Anxiety

-Delirium

- Hypertension

- Tachycardia

- Hyperpyrexia- Mydriasis

- Diaphoresis

Possible toxins

- Cocaine, Amphetamines, phencyclidine

(PCP), Lysergic acid (LSD)

- Withdrawal from narcotics,

benzodiazepine, alcohol, long term beta-

blocker therapy

Cholinergic toxidrome

8.2.1 Clinical evaluation of the poisoned patient

The clinical evaluation of the poisoned patient has the primary objective of triaging

poisoned patients into mild, moderate and severe categories of poisoning by obtaining a

targeted history, performing a careful physical examination and specific laboratory

evaluation. This will not only help prognosticate but also determine the extent of

therapeutic interventions and type of in-patient resources that need to be committed in

each case.

8.2.2 History

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• Fact finding mission – From patient, paramedics, family, friends, circumstantial evidence

such as empty packets, vomitus with pill fragments.

• Who was exposed? Demographic information including age, sex, weight.

• What was ingested? Name of agent and type of formulation e.g. tablets or liquid,

extended release, ingredients on combination tablets, concentration of active compounds

etc.

• What else was ingested? Any other co-ingestant especially medications from other

physicians, alcohol, traditional medications and health supplements.

• How much exposure?

• When did poisoning occur? Exact timing of ingestion or timings of ingestion episodes.

• What were the post exposure symptoms?

• How was patient exposed to toxin?

• Why exposed? The reason for toxic exposure accidental versus intentional.

• AMPLE history? As for any patient with trauma an AMPLE history comprising history of

allergies, medications patient is regularly on, past medical problems, last meal and drink,

and events that led to the poisoning as outlined above should be obtained.

8.2.3 Examination

• Use all your senses to search for the clues:

– LOOK

o Track marks in cubital fossa and groin suggestive of intravenous drug abuse.

o Residue deposits around mouth nose, body surface.

o Unusual colour of vomitus, urine.

– FEEL

o Temperature, sweating.

– SMELL

o Alcohol and other unique odours.

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• Assess ABCDE:

– Airway & Breathing

o Ability to protect airway.

o Respiratory rate & depth.

o Oxygen saturation.

– Circulation

o Pulse rate and regularity.

o Blood pressure.

– Disability

o Glasgow Coma Scale (GCS).

o Pupil size and equality.

o Do random glucose to exclude hypoglycaemia.

– Exposure

o To look out for external evidence of trauma such as head injury that may provide an

alternative explanation for patient’s condition.

8.2.4 Toxicological investigations

Targeted investigations are to be done in toxic exposures that supplement clinical

evaluation.

The following is a list of some of the useful investigations.

• Random bedside glucose.

• ECG (electrocardiogram).

• Serum electrolytes and renal function.

• Liver function test.

• Creatine kinase.

• Full Blood Count.

• Clotting screen: PT/PTT/INR.

• Arterial blood gas.

• Specific toxin level e.g. serum paracetamol, salicylate, phenobarbital, theophylline,

• Serum osmolality and osmolality gap.

• Abdominal X-ray may be useful in diagnosing certain radiopaque toxins

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• Others e.g. CXR, CT.

8.3 Therapeutic interventions for poisoning

8.3.1 Gastric decontamination

Removal of unabsorbed poison from the gut can be achieved by several means including

induction of emesis, gastric lavage, and use of activated charcoal and cathartics. Before

performing a procedure for gastric emptying, it is important to consider:

i) Whether the ingestion is potentially dangerous,

ii) Can the procedure remove a significant amount of toxin, and

iii) Whether the benefits of a procedure outweigh its risks?

Gastric emptying is not indicated if the patient had prior repeated vomiting or the toxin is

absorbed rapidly, or patient presents late after ingestion.

Syrup of ipecac : Syrup of ipecac is used to induce emesis with the intention to remove the

poison from the stomach. Presently, ipecac may be considered in an alert conscious patient

who has ingested a potentially toxic amount of a poison within the last one hour. It should

be avoided in ingestion of hydrocarbons and corrosives.

Gastric lavage : For inserting an orogastric lavage tube, the patient should be placed in left

lateral position with the head-end lowered. A large bore tube (36 F in adults) is inserted into

the stomach and its position is checked by injecting air through the tube into stomach and

simultaneously auscultating over the epigastrium. The lavage is then performed by using

fluid aliquots of 3-4 ml/kg. The lavage is continued till the return is clear.

Cathartics : Cathartics have been used for several years with the hope of increasing the

excretion of the toxins from the gut. Commonly used cathartics are magnesium sulphate (30

g for adults and 250 mg/kg in children), magnesium citrate (4 ml/ kg up to a maximum of

300 ml) and sorbitol (1 g/kg as 70% solution).

Activated Charcoal : Use of activated charcoal has revolutionized the treatment of

poisoning. Due to its small particle size and enormous surface area, it can adsorb large

amount of toxins. The usual dose is 1 g/kg body weight or 10 parts of charcoal for every one

part of toxin, whichever is greater.

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Whole bowel irrigation: In this method, isotonic solution of polyethylene glycol-electrolytes

is administered orally in a dose of 2 litre/hour in adults and 0.5 litres/hour in children. The

procedure is continued for 4-6 hours or till the rectal effluent is clear.

8.3.2. Enhancing Excretion

Once the absorption of a toxin has been reduced by various methods, the next logical step is

to enhance the elimination of already absorbed toxin from the body.

Forced alkaline diuresis: One of the commonly used methods to increase the elimination of

a toxin is forced diuresis with alteration in urine pH. The renal tubular epithelium is

relatively impermeable to the ionized molecules. If the urinary pH is changed so as to

produce more of ionized form of a chemical, it is trapped in the tubular fluid and is excreted

in the urine. This is the basis for alkaline diuresis which is useful in salicylates, Phenobarbital

and lithium intoxication. For alkaline diuresis, 5% dextrose in half-normal saline containing

20-35 mEq/L of bicarbonate is administered at a rate so as to produce a urine output of 3-6

ml/kg/hour and a urine pH 7.5- 8.5.

Multiple-doses of activated charcoal: Multiple doses of activated charcoal have been

recommended in treating certain poisonings. Because of multiple doses, free charcoal is

available in the intestines to bind any toxin which has significant enterohepatic circulation.

Further, free toxin in the blood tends to diffuse out of the blood into the intestines where it

binds the charcoal, thereby maintaining the concentration of free toxin in the intestines

near zero. This is termed “gastrointestinal dialysis”. Depending upon the severity of

poisoning, the doses are 0.5-1 g/ kg body weight every 1-4 hours.

Dialysis: Peritoneal and haemodialysis are useful for water-soluble compounds of low

molecular weight. Dialysis is useful in ethanol, methanol, salicylates, theophylline, ethylene

glycol, phenobarbital and lithium intoxications. Peritoneal dialysis is a slow process and it

should not be used if facilities for haemodialysis are available.

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8.3.3. Antidote

An antidote is a drug used to neutralize or counteract the effects of poisoning. There are

many drugs and chemicals that can cause toxicity, but only about 40 specific antidotes

available for use in acute and chronic poisoning. The use of antidotes should be guided by

assessment of the risk-benefit ratio.

Naloxone is used to rapidly counteract the sedation and respiratory depression induced by

opiates.

Ethanol is recommended in methanol, ethylene glycol poisoning in a loading dose of 0.75

g/kg which is followed by maintenance dose of 0.1 g/kg/hr.

8.4. Supportive Therapy

Since the antidotes are available only for a few toxins, treatment of most cases of poisoning

is largely supportive. It is important not to waste time in locating an antidote; instead

supportive therapy should be instituted after which an attempt may be made to get the

antidote. The aim of the supportive treatment is to preserve the vital organ functions till

poison is eliminated from the body and the patient resumes normal physiological functions.

Therefore, functions of central nervous system, cardiopulmonary system and renal system

should be supported with proper care for coma, seizures, hypotension, arrhythmias,

hypoxia, and acute renal failure. The fluid, electrolyte and acid-base status should be closely

monitored in all patients.

9. Poison prevention

Only take prescription medications that are prescribed by a healthcare professional.

Never take larger or more frequent doses of your medications, particularly

prescription pain medications, to try to get faster or more powerful effects.

Never share or sell your prescription drugs.

Follow directions on the label when you give or take medicines.

Turn on a light when you give or take medicines at night so that you know you have

the correct amount of the right medicine.

Keep medicines in their original bottles or containers.

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Monitor the use of medicines prescribed for children and teenagers, such as

medicines for attention deficit hyperactivity disorder, or ADHD.

Dispose of unused, unneeded, or expired prescription drugs.

Always read the label before using a product that may be poisonous.

Keep chemical products in their original bottles or containers. Do not use food

containers such as cups, bottles, or jars to store chemical products such as cleaning

solutions or beauty products.

Never mix household products together. For example, mixing bleach and ammonia

can result in toxic gases.

Wear protective clothing (gloves, long sleeves, long pants, socks, shoes) if you spray

pesticides or other chemicals.

Turn on the fan and open windows when using chemical products such as household

cleaners.

10. Conclusion

Poisoning is a significant global public health problem. According to WHO data, nearly a

million people die each year as a result of suicide, and chemicals account for a significant

number of these deaths. It is estimated that deliberate ingestion of pesticides causes

370,000 deaths each year. The number of these deaths can be reduced by limiting the

availability of, and access to, highly toxic poisons.

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11. References

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2. Ponampalam R, HH Tan, KC Ng, et al. Demographics of Toxic Exposures Presenting to

Three Public Hospital Emergency Departments in Singapore 2001 – 2003. J Emerg

Med 2009 April;2(1):25–31. Published online 2009 February 4. doi: 10.1007/s12245-

008-0080-9. PMCID: PMC2672975.

3. Ponampalam R. An Unusual Case of Paralytic Ileus after Jellyfish Envenomation.

Emergency Medicine Journal 2002;19:357-8.

4. Lerner WM, Warner KE. The challenge of privately-financed community health

programs in an era of cost containment: A case study of poison control centers. J Pub

Health Pol 1988;9:411-28.

5. Harrison DL, Draugalis JR, Slack MK, et al. Cost-effectiveness of regional poison

control centers. Arch Intern Med 1996;156:2601-8.

6. Miller TR, Lestina DC. Costs of poisoning in the United States and savings from

poison control centers: a benefi t-cost analysis. Ann Em Med 1997;29:239-45.

7. Mvros R, Dean BS, Krenzelok EP. Poison center funding - who should pay? J Toxicol

Clin Toxicol 1994;32:503-8.

8. Aggarwal P, Wali JP (eds.) Diagnosis and Management of Acute Poisoning, Oxford

University Press Delhi 1997; pp 1-38.

9. Wikipedia free encyclopedia website: http://en.wikipedia.org

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poisoning

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