Paediatric toxicological emergencies: medical intervention in cases of paediatric poisoning

By Cristiano Antonino Last updated Oct 14, 2022

Intervention in paediatric toxicological emergencies: exposure to toxic substances frequently occurs in children

Common patterns of paediatric poisoning consist of exploratory ingestions in children under 6 years of age and intentional ingestion and recreational drug use in older children and adolescents.

Exposure to toxic substances must be taken into account when children with

multi-organ system dysfunction
altered mental status
respiratory or cardiac impairment
metabolic acidosis
convulsions or
an unexplained condition.

The index of suspicion should be elevated if the child is in the ‘at risk’ age group (1-4 years) and/or has a previous history of ingestion.

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Intentional poisoning includes child abuse in young children and suicide attempts in older children/adolescents.

Medical abuse of minors through forcible ingestion in young children, particularly those under one year of age, should always be considered.

Toxicological emergencies: Toxidromes (TOXIc + synDROMES)

Toxidromes are syndromes of poisoning.

The categories may overlap but, in general, they are divided into

sympathomimetic agents and adrenergic blockers
cholinergics and anticholinergics,
hallucinogens,
opioids,
sedatives/hypnotics and
serotonin syndrome.

Sympathetic addicts

SYMPHATOMETICS: substances that stimulate the sympathetic nervous system.

These are usually stimulants, which cause

hypertonia,
agitation,
hallucinations and
paranoia.

COMMON CULPRITS:

Cocaine
Amphetamines
Ephedrine
Pseudoephedrine
Theophylline
Caffeine
Catinones

SIGNS AND SYMPTOMS OF TOXICOLOGICAL EMERGENCIES

Mental state: Hyper-alarm, agitation, hallucinations, paranoia.
Vital signs: Hyperthermia, tachycardia, hypertension, tachypnoea, increased pulse pressure, diaphoresis, tremors, hyperreflexia and convulsions.

ADRENERGIC BLOCKING AGENTS:

Alpha-adrenergic blockers: hinder the action of noradrenaline, allowing the vessels to remain open.

Used for hypertension. Examples: Doxazosin, Prazosin, Terazosin. S&S: headache, palpitations, weakness, dizziness.

Beta-adrenergic blockers: for hypertension, arrhythmia, migraine.

Examples: Atenolol, Metoprolol, Nadolol, Propranolol.

SIGNS AND SYMPTOMS

Bradycardia and hypotension are the most common effects; also

dizziness,
weakness,
fatigue,
cold hands/feet,
dry mouth,
headaches,
stomach ache,
diarrhoea/contiption,
changes in mental state,
hypoglycaemia,
bronchospasm.

Calcium channel blockers: act by blocking calcium to relax arterial smooth muscle and block channels in the pericardium.

S&S: hot flushes (arterial vasodilatation), tachycardia and, at higher doses, decreased cardiac inotropy and bradycardia.

Cholinergic and anticholinergic toxins

CHOLINERGIC: could be called the ‘parasympathetic’ toxidrome, because it stimulates the parasympathetic nervous system (PNS) by stimulating receptors for the main neurotransmitter, acetylcholine.

The PNS is involved in the body’s regulatory systems, which are reflected in P&S.

Insecticides
Nerve agents
Nicotine
Pilocarpine
Physostigmine
Edrophonium
Bethanechol
Urecholine

SIGNS AND SYMPTOMS

Mental status: Confusion, coma.
Vital signs: Bradycardia, salivation, incontinence, diarrhoea, emesis, diaphoresis, bronchoconstriction, weakness and convulsions.

ANTI-CHINERGENS: they compete with PNS receptors against acetylcholine.

Antihistamines
Tricyclic antidepressants
Cyclobenzaprine
Anti-Parkinson’s agents
Phenothiazines
Atropine
Scopolamine
Belladonna alkaloids

SIGNS AND SYMPTOMS

Mental status: Hypervigilance, agitation, hallucinations, delirium with mumbling, coma.
Vital signs: Dry, flushed skin, dry mucous membranes, decreased bowel sounds, urinary retention, myoclonus, picking behaviour.

The classic description of anticholinergic poisoning…

Red as a beet (skin vasodilation)
Dry as a bone (inhibition of sweat glands)
Hot as a hare (interference with sweating -> hyperthermia)
Blind as a bat (mydriasis – dilatation)
Mad as a hatter (delirium, hallucinations)
Full as a flask (full bladder due to reduced contractions and closed sphincter)

Toxicological emergencies: hallucinogenic substances

Phencyclidine
LSD
Mescaline
Psilocybin
Synthetic amphetamines (e.g. MDMA, MDEA)

SIGNS AND SYMPTOMS:

Mental state: Hallucinations, perceptual distortions, depersonalisation, synesthesia, agitation.
Vital signs: Nystagmus.

Opioid toxic substances

OPPIOIDS:

Heroin
Morphine
Methadone
Oxycodone
Hydromorphone
Hydrocodone
Diphenoxylate

SIGNS AND SYMPTOMS:

Mental state: CNS depression, coma.
Vital signs: Hyporeflexia, pulmonary oedema, needle marks.
Sedative/hypnotic addicts

SEDATIVES/HYPNOTICS:

Benzodiazepines (Valium, Xanax)
Barbiturates
Carisoprodol (Soma)
Meprobamate
Glutethimide
Alcohols
Zolpidem

SIGNS AND SYMPTOMS

Mental state: CNS depression, confusion, stupor, coma.
Vital signs: Hyporeflexia.

Serotonin syndrome

Life-threatening condition of serotonin excess caused by SSRI (serotonin reuptake inhibitors) toxicity and other drug interactions and excesses.

Monoamine oxidase inhibitors (MAOIs)
SSRIs (serotonin reuptake inhibitors, e.g. Prozac, Zoloft, etc.)
Meperidine (Demerol)
Dextromethorphan
Tricyclic antidepressants
L-tryptophan

SIGNS AND SYMPTOMS:

Mental state: Confusion, agitation, coma.
Vital signs: Tremor, hyperthermia, myoclonus, hyperreflexia, clonus, diaphoresis, flushing, trismus, rigidity, diarrhoea, goose bumps.

Paediatric toxicological emergencies with over-the-counter drugs

Antihistamines

S&S: at low doses, sedation; at higher doses, anticholinergic poisoning.
Reddened and dry skin, hyperthermia, blurred vision, agitation, tremor, convulsions.
Alpha-1 adrenergic decongestants
S&S: hypertension, tachycardia, mydriasis, diaphoresis, agitation.

Antipyretics and analgesics (acetaminophen, ibuprofen, aspirin)’

S&S: nausea, vomiting, lethargy, malaise, right upper quadrant pain and possible liver failure → death.

Antitussives (cough suppressants):

Cough and cold medicines containing dextromethorphan are commonly used recreationally by youth and adults.

S&S: euphoria, laughter, psychosis, agitation, coma, tachycardia, mydriasis, nystagmus, diaphoresis, zombie-like gate.

Over-the-counter cough and cold medicines have been associated with fatal overdoses in children under the age of two.

Expectorant (guaifenesin)

Guaifenesin is relatively safe and causes mild gastrointestinal irritation, but in OTC drugs guaifenesin is usually combined with other ingredients, which may cause bronchospasm, gastrointestinal discomfort and fever.

Ethanol in adult formulations:

Administered to children, it can cause hypoglycaemia.

Ethanol-containing products other than alcoholic beverages (e.g. perfumes, colognes, mouthwashes and ethanol-based hand sanitisers) account for 85-90% of these exposures.

Ethanol-based hand sanitisers, applied generously, often or over large areas of skin, may cause systemic absorption of ethanol.

Ethanol intoxication generally masks the tachycardia, pupil dilation and diaphoresis commonly associated with hypoglycaemia.

S&S: CNS depression, convulsions caused by hypoglycaemia (especially in infants and young children).

Camphor:

Used topically for coughs and nasal decongestion, some types combine it with menthol (e.g. Vick’s Vaporub). Toxicity may result from oral or topical ingestion.

S&S: convulsions (may be the first sign of exposure!), N&V, agitation, confusion, hyperreflexia, lethargy or coma.

Common toxic substances in case of abuse

Poison need not be exotic or a drug created to kill.

Salt, pepper, legitimately prescribed drugs, over-the-counter medicines and even water can cause toxicity when part of an abuse.

Munchausen-by-proxy: when a parent has a psychiatric disorder that drags their child into their hypochondriac paranoia.

Water: forced intake of water causes hyponatriemia, leading to convulsions, vomiting, coma or death. It may be administered as punishment and signs of other abuse are often present.

Salt: typically in the first 6 months of life, with hypernatremia.

Aspirin:

Salicylate toxicity is known as ‘salicylism’.

It may be acute, chronic or acute-on-chronic.

It is rare in children.

S&S: hyperpnoea, tachypnoea, metabolic acidosis and possible tachycardia.

Early symptoms are

tinnitus, dizziness, nausea, vomiting and diarrhoea;
more severe intoxications may cause fever, altered mental state, coma, pulmonary oedema and death.

Acetaminophen: ‘the forgotten poison

When collecting the medical history, practitioners may neglect to include acetaminophen because of its OTC status which leads them to think it is unimportant.

Rapid identification of acetaminophen toxicity is essential because the antidote, N-acetylcysteine (NAC), is most effective when administered within 8-10 hours of acute acetaminophen ingestion.

S&S: nausea, vomiting, lethargy, malaise, right upper quadrant pain and possible liver failure → death.

Caustic substances in paediatric toxicological emergencies

Half of the millions of toxic exposures to caustic agents involve children under 5 years of age.

The most commonly ingested caustic substances are cleaning products (11%).

ACID pH < 2: causes oesophageal injury by coagulative necrosis. This self-limiting coagulation makes perforation less common than exposure to alkalis. Upper airway injuries are more common with ingestion of acids due to their bad taste which stimulates gagging, choking and attempts to spit out the ingested material.

ALKALI pH > 11.5: causes oesophageal lesions by liquefaction necrosis, with deep penetration and even perforation. The depth of the lesion depends on the exposure time.

Button batteries in the oesophagus can cause rapid injury to the oesophagus and surrounding critical structures due to the escape of alkaline material.

P&S: The most common symptom is dysphagia, even with mild oesophageal injury.

Inhalations

The lungs provide a rich vascular bed for the ingestion of toxic substances.

Toxic substances quickly enter the body and bypass hepatic detoxification.

Inhalation is also used as a method of drug abuse.

The lungs, which are essential for ventilation/respiration, can be damaged by inhaled caustic substances, impairing oxygenation.

The most common causes of inhalation lung injury are exposure to occupational and environmental agents, particularly inorganic or organic dusts.

The main injury to the upper airways is thermal damage, which causes erythema, ulceration and oedema.

Damage to the ciliary function hinders the movement of substances out of the airways, increasing the risk of bacterial infection.

Injuries to the tracheobronchial tree are usually caused by chemicals in smoke or vapour, as well as by toxic inhalation of noxious gases (e.g. chlorine) or liquids (e.g. acid).

Carbon monoxide is one of the most frequent immediate causes of death from inhalation injuries.

Caution: Pulse oximetry cannot detect carbon monoxide exposure, as it cannot differentiate carboxyhaemoglobin from oxyhaemoglobin due to the similarity in colour of both in the blood.

Cyanide poisoning is rapidly fatal if not treated with an antidote.

Treatment should be considered for anyone who has been treated for smoke inhalation or who shows a depressed level of consciousness, cardiac arrest or heart failure in the absence of laboratory confirmation.

Patient assessment in paediatric toxicological emergencies

HISTORY: time of ingestion/exposure, amount ingested, abnormal symptoms, bottles/containers available.

PHYSICAL FINDINGS: all vital parameters, airway/breathing/circulation, pupils.

Also note diaphoresis, mental status and any fever.

Rapid assessment of

mental status,
vital signs and
pupils

… allows you to classify the patient in a state of:

physiological arousal (e.g. central nervous system stimulation and increased temperature, pulse, blood pressure and respiration)
depression (depressed mental state and decrease in temperature, pulse, blood pressure and respiration); or
mixed physiological state.

This initial characterisation helps direct initial stabilisation efforts and provides a clue to the aetiological agent.

PUPILLARY TAB:

MYODRIASIS (pupil dilation):

sympathomimetics (phenylephrine, pseudoephedrine, decongestants);
antihistamines;
anticholinergics;
hallucinogens (usually);
serotonin syndrome.

MYOSIS (pupil constriction):

quoninergics;
opioids.

Sedatives/hypnotics may cause mydriasis or miosis.

Management

WARNING: The worst must be assumed. For example, if a bottle is empty or there are only a few pills left, you should assume it was full before the accident.

BLOOD GLUCOSE

Ethanol: Rapid measurement of blood glucose should be performed in all patients, particularly infants and young children with altered mental status.

If low, blood glucose should be corrected and then serially monitored, particularly in younger children or those with limited glycogen reserves who may be at risk of recurrent hypoglycaemia.

Caution:

with anti-hypertensives,
hyperglycaemia occurs more often with calcium channel blocker toxicity,
whereas beta-blockers are associated with hypoglycaemia.

DECONTAMINATION

Gastrointestinal decontamination: removal of an ingested toxin to decrease its absorption.

This can be done directly or indirectly.

Direct decontamination is done by inducing vomiting or by gastric lavage, but these are no longer recommended.

Gastric lavage has been abandoned.

Induced vomiting (Ipecac syrup) is no longer recommended.

Indirect administration is by the nasogastric route with activated charcoal or by accelerating the transit time in the gastrointestinal tract to speed up elimination via the faeces.

Cathartics: accelerating rectal elimination is not recommended.

Dilution: no longer recommended.

The use of activated charcoal is preferable within one hour of ingestion.

It should not be used in cases of altered mental state because of the risk of aspiration.

It does not work well with metals (iron, lithium), alkalis, mineral acids or alcohols.

Aspiration is the concern most often cited when doctors choose not to administer activated charcoal.

Rx: Children up to one year of age: 10 to 25 g, or 0.5 to 1.0 g/kg.

Rx: Children 1 to 12 years of age: 25 to 50 g, or 0.5 to 1.0 g/kg (maximum dose 50 g).

Rx: Adolescents and adults: 25 to 100 g (50 g is the usual dose for adults).

Topical irrigation: best for skin and eye exposure

Immediate irrigation with water is the essential first aid for chemical burns of the skin and eyes, reducing the risk of chronic conjunctivitis and sight-threatening corneal ulceration.

For the eyes, copious irrigation with water dilutes and removes most chemicals.

Moderately warm, high volume but low pressure water should be used for irrigation.

High-pressure irrigation, which can make the corrosive splash, should be avoided.

Irrigation may require a topical analgesic for the eyes.

For the skin, a much longer irrigation period is required for alkali exposure than for acid exposure: 2 hours or more of continuous irrigation may be required before the pH of tissues exposed to a strong alkali returns to neutral.

Antidotes: Administration of antidotes is appropriate for poisons that have antidotes and:

the severity of the poisoning justifies it,
the benefits outweigh the risks and there are no
contraindications.

Dialysis: removes toxic methanol and ethylene glycol metabolites, corrects acid-base abnormalities and reduces end-organ damage and mortality associated with these poisonings.

Haemoperfusion: uses a carbon membrane between the exit and re-entry of blood into the body.

Oxygen and bronchodilators: for inhalation injuries.

In the field, supportive care is the cornerstone of the treatment of the poisoned patient.

However, there are cases where the timely administration of an antidote can save a life.

Naloxone:

Rx: Administer naloxone to patients with signs, symptoms or history of opioid intoxication.

Naloxone is not recommended for neonatal resuscitation because data on its safety, dosage and efficacy are lacking.

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