Editors

MariaKratz

Treatment of Poisoning

Essentials

Airway patency and respiration and circulation should be assessed and supported immediately, as necessary (ABCDE principles, see e.g. Prehospital Emergency Care).
Simultaneously with examination and risk assessment, exposure should be stopped, as far as possible, and prevention of absorption of the toxic substance started (alimentary tract, skin), using medicinal charcoal, in particular, if charcoal binds the causative agent.
If the patient history and risk assessment suggest severe poisoning, the patient should be transferred without delay to a facility with sufficient possibilities for treatment.
- Some cases of poisoning require rapid start of elimination of the toxic substance (such as dialysis) or of administration of a specific antibody even if the patient is relatively asymptomatic on assessment.
The patient may have other injuries or diseases than ones related to the poisoning.
For special features of poisoning in children, see Poisoning in Children; for special features in the elderly, see Treatment of Poisoning in the Elderly.
The local/national poison information center should be readily consulted.

Risk assessment

In risk assessment, the causative agent and any detected disturbance or suspected development of disturbance of essential body functions should be considered, as well as whether the patient is dangerous to him-/herself or to others.
- There are often mental disorders, substance abuse or both behind poisoning. A psychiatrist should be consulted or safeguarding arranged, as necessary.
- In the case of minors (particularly if intoxicated), child welfare notification should be submitted, as necessary.
- The need for psychosocial support for the patient or his/her relatives should be considered.
-When assessing the causative agent, particularly the following should be utilized:
- information given by those who provided initial treatment or otherwise accompanied the patient from the site
- prescription database for the patient's medication
- local/national poison information center (keep contact information available).

Causative agents

The most common cause of poisoning requiring treatment is ethanol or a combination of ethanol and legal or illegal drugs or surrogate alcohol (see Alcohol Poisoning).
Carbon monoxide, combustion fumes and chemical poisonings are seen more rarely, and severe mushroom or plant poisonings very rarely (see Carbon Monoxide Poisoning).
Insidious causative agents include drugs such as paracetamol and tricyclic antidepressants (see Drugs Commonly Causing Poisonings ).
Nicotine is dangerous for small children even in very low doses; see Poisoning in Children. In adults, dangerous nicotine poisoning is mainly due to deliberate abuse, such as swallowing the liquid from electronic cigarettes.
Chemicals are an immense group of substances and mixtures; on exposure to these, the risk of poisoning varies considerably, from nonexistent to life-threatening.
- Symptoms and injuries may sometimes develop with significant delay.
- It would be important to know the exact composition of the substance or mixture, and it is always worth contacting the local/national poison information center for such investigations http://www.hus.fi/potilaalle/sairaalat-ja-toimipisteet/myrkytystietokeskus.

Investigation of exposure

The causative substance/s, their amount/s, time and duration of exposure
In the case of drugs, the name, strength, characteristics of the dosage form (such as slow absorption, etc.)
- The estimated amount taken based on the amount left in the package, the time of purchase from a pharmacy and previous daily doses
- Regular medication and tolerance
In the case of chemicals, efforts should be made to find out the name of the product, its pH, its contents and other characteristics, as well as the hazard labelling on the package.
- This information may be most quickly available from the local/national poison information center, which should be readily consulted at an early stage. The health data and first aid instructions given in chemicals' safety data sheets are not always reliable.
In the case of plants and mushrooms, characteristics and the growing environment should be investigated.
- For identification, some of the plant or mushroom may be placed in a box or photographed or both.
On admission, blood and urine samples should be taken for later analyses and any medicolegal investigations (blood and urine intoxication examinations).
- The time of taking the samples should be clearly marked.

Prevention of absorption

Prevention of absorption is one of the primary methods of treating poisoning.
In acute poisoning, medicinal charcoal is the most effective means of preventing the absorption of the toxic substance.
- In patients who have been given medicinal charcoal, it also prevents the absorption of oral medication.
- The contraindications should be taken into consideration (Table T1).
In certain cases of life-threatening poisoning, gastroscopy and intestinal lavage to eliminate drugs can be considered after consulting the local/national poison information center, primarily in specialized care. Gastric lavage is hardly ever performed any more.
The efficacy of medicinal charcoal is at its best within less than an hour from overdose but there is no definite time limit for giving it.
- In high overdoses, drugs may be absorbed more slowly.
- Many anticholinergic drugs (such as psychotropic drugs) may slow down gastric emptying and therefore be slowly absorbed.
Medicinal charcoal should not be given to patients with poisoning caused by substances listed in Table T1.
- As some tablets not bound by charcoal are x-ray positive (iron and potassium chloride, for example), x-raying can be used to confirm whether there are such tablets in the patient's body.

The prerequisites and contraindications for giving medicinal charcoal, and types of poisoning where it is ineffective.

Prerequisites for giving medicinal charcoal	Sufficient level of consciousness (response to speech, GCS > 8) or intubated patient, so that charcoal can be given via a naso- or orogastric tube
	Conscious patient capable of cooperation and willing to cooperate
	No risk of gastrointestinal bleeding, perforation or obstruction (such as recent surgery in the region)
Medicinal charcoal contraindicated	Caustic/corrosive agents, such as acids or bases
Medicinal charcoal ineffective	Alcohol
	Iron, lithium
	Petroleum products
	Fluoride, cyanide, potassium chloride

Dosage and administration

The product can be given either as a drink or via a naso- or orogastric tube.
The single dose for adults is 50(-100) g, i.e., either
- 1(-2) bottle(s) of charcoal suspension (50 g) or
- 200(-400) 250-mg charcoal tablets crushed and mixed with water.
The single dose for children is 1 g/kg of suspension or tablets.
- charcoal suspension (50 g/240 ml bottle): 3 tbsp. per 10 kg (up to 50 g) mixed with water or other drink or food
- 250-mg charcoal tablets: 4 tablets per kg (i.e. 40 tablets for a child weighing 10 kg)

Symptoms and findings

The causative agent may affect the whole body or a certain organ, tissue, cell or gene.
- Look for topical effects, such as that of a caustic agent on the skin
Symptoms may occur with delay, sometimes as late as after several days.
- The patient's condition may deteriorate rapidly.
- The harmful effect may only be caused by metabolic products or as the substance is slowly absorbed from a depot product, for example.

Severe poisoning

Symptoms of severe poisoning should be assessed and treated according to the ABCDE approach (see e.g. Prehospital Emergency Care).
- Most patients need intensive care or intensified monitoring; see Table T2.
An overdose leading to severe poisoning is usually intentional in adults and unintentional in children.

Indications for intensive care or (intensified) monitoring of patients with poisoning. The specific place of treatment should be chosen based on local guidelines.

Intensive care	Need to ensure a patent airway, respiratory failure
	Haemodynamic failure, actual or impending severe arrhythmia (torsades de pointes, long QT interval, QRS > 120 ms, bradycardia)
	Decreased level of consciousness, agitation or confusion, convulsions
	Evident disturbance of the acid-base balance, electrolyte disturbances that are difficult to treat or hypoglycaemia, hyperthermia
	Acute renal damage or liver failure
	Need for extracorporeal treatment
(Intensified) monitoring	Poisoning with minor symptoms if there is reason to suspect delayed drug absorption
	Severe withdrawal symptoms
	Need for rarer antidotes
	Poisoning caused by newer pharmaceuticals or designer drugs with lack of experience of treatment

Workup

The required workup should be chosen depending on the patient's symptoms, history of diseases and other history, such as the suspected causative agent.
When ordering tests, their characteristics (how quickly the results can be obtained, reliability) and effect on treatment should be considered.
Routine toxicological screening is not indicated, and a negative result from a drug screen does not exclude severe poisoning.
Rapid tests (saliva or urine dipstick tests) and immunochemical urine drug screening are unreliable.

Determination of blood concentrations

Determination of blood concentrations can be considered in specialized care if there is a specific pharmacological treatment available for the substance or if it is dialyzable.
- Paracetamol concentrations should be readily determined in any unclear situation.
- In case of metabolic acidosis or lactacidaemia, test for toxic alcohol levels.
If slow development of overdose or chronic poisoning associated with the patient's medication is suspected, the levels of valproic acid, digoxin and certain other drugs can be measured for adjusting the dosage.
- See also Treatment of Poisoning in the Elderly.

Forensic chemical samples

In all severe, unclear or unusual cases of poisoning, forensic chemical samples should be taken in specialized care on admission.
- They are analyzed if the patient dies or suspicion of crime arises.
- The analysis is performed in a forensic chemical laboratory.
- Analysis is required by the police.
Blood should be drawn and also urine and stomach contents taken, as far as possible, because therapeutic measures and metabolism affect the levels of causative agents.

Treatment

If the patient has significant disturbances of essential body functions, life-saving treatment (ensuring adequate airway, breathing and circulation) must be started immediately, while ensuring the quickest possible start of transportation. Some of the treatment can be started/continued by prehospital emergency care, then in the specialized care hospital emergency department and in an intensive care and surveillance unit, as considered necessary.
Absorption of the toxin should be prevented by giving medicinal charcoal as soon as possible, unless there are contraindications; see Table T1.
Severe poisoning should be treated in an intensive care and surveillance unit (see Table T2).
- The principles of treatment do not differ from those of normal intensive care, with the exception of the methods used for eliminating the poison and reducing its effects.
- Specific antidotes may be useful if the causative agent is known.
- In intensive care, methods such as elimination of the poison by dialysis or extracorporeal membrane oxygenation (ECMO) can be used in case of calcium-channel blocker or beta blocker poisoning causing circulatory collapse, for example.
Respiratory failure is the most common mechanism leading to death from poisoning.
- The targets of ensuring airway patency, oxygenation and ventilation are SpO₂> 95%, normocapnia (ETCO₂ 4-6) and prevention of aspiration.
Convulsions are a sign of severe intoxication and require immediate assessment and monitoring even if the attack is brief and self-limiting.
- The first-line anticonvulsant treatment is always a benzodiazepine.
Hyperthermia may be caused by serotonergic drugs, MAO inhibitors, MDMA and many stimulant drugs, for example.
- Body temperature should be routinely measured in all patients with poisoning. Even rather low temperatures should be reacted to, as the temperature may rise in a few minutes to alarmingly high levels because of drug action or muscle activity due to convulsions. In patients with convulsions, an ear thermometer is more reliable than an axillary thermometer in measuring body temperature.
- As first aid, external cooling should be started by undressing the patient and removing any covers. Agitation and muscle activity can be reduced by sedation (benzodiazepines). Physical restriction, such as restraints, should be avoided because it typically increases agitation.
- In intensive care, more extensive sedation, intravenous hypothermia catheters and external cooling blankets can also be used.
Agitation can be caused by, for instance, illegal and legal drugs stimulating the central and autonomic nervous system, mental health problems and intoxication, or alcohol, benzodiazepine or opioid withdrawal symptoms. Its primary treatment is intravenous diazepam. General anaesthesia may be required if agitation is associated with hyperthermia.