Exposure to Poisonous Substances

Description

General Measures

Medicine Treatment

Referral

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ICD-10 code: T36.0-9/T37.0-5/T37.8-9/T38.0-9/T39.0-4/T39.8-9/T40.0-9/T41-0-5/T42.0-8/T43.0-6/T43.8-9/ 4.0-9/T45.0-9/T46.0- 9/T47.0-9/T48-0-7/T49.0-9/T50.0-9/T51.0-3/T51.8-9/T52.0-4/T52.8-9/T53.0-9/T54.0-3/T54.9/T55/T56.0-9/T57.0- 3/T57.8-9/T58/T59.0-9/T60.0-4/T60.8-9/T65.0-6/T65.8-9+ (X44.99/X49.99/X64.99/X69.99/Y14.99/Y19.99)

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Note:
Poisoning from all pesticides (i.e. agricultural stock remedies) is a notifiable medical condition. Please visit www.nicd.ac.za for further information.

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Table 21.11: Poison information centre(s) 

Poison Information Centres
Poisons Information Helpline (national service)	24 hours/day	0861 555 777
Red Cross War Memorial Children’s Hospital Poisons Information Centre Email: poisonsinformation@uct.ac.za  http://www.paediatrics.uct.ac.za/poisons-information-centre
Tygerberg Poisons Information Centre Email: toxicology@sun.ac.za www.sun.ac.za/poisoncentre
University of the Free State Poison Control and Medicine Information Centre	24 hours/day	082 491 0160
Telephone numbers tested April 2022

The Afritox database is available free of charge to public hospitals in South Africa: see www.afritox.co.za for information on how to access the database. If the above centres cannot be contacted, enquire at the nearest trauma and emergency unit.

DESCRIPTION

Acute poisoning is a common medical emergency. Poisoning may occur by ingestion, inhalation, or absorption through skin or mucus membranes. Frequently encountered poisons include:

• analgesics
• pesticides
• anti-epileptic agents
• volatile hydrocarbons, e.g. paraffin
• antidepressants and sedatives
• household cleaning agents
• anti-infectives
• antihypertensive and anti-diabetic agents
• vitamins and minerals, especially iron in children

Signs and symptoms vary according to the nature of poisoning.

GENERAL MEASURES

• Establish and maintain the airway.
• Ensure adequate ventilation and oxygenation.
• Treat shock. See: Cardiopulmonary arrest.
• Take an accurate history.
• Obtain collateral information, especially in patients with impaired consciousness.
• A special effort should be made to obtain tablets, packets, containers, etc. to identify poisons involved.
• Document, and respond to, abnormalities of:
  • pulse rate
  • blood pressure
  • level of consciousness
  • pupillary size and reaction
  • respiratory rate
  • oxygenation

Remove the patient from the source of poison:

• Topical exposure:
  • If skin contact has occurred, especially pesticides, wash the skin with soap and water, ensuring carer has protective measures, e.g., gloves, gowns, masks, etc.
  • Remove contaminated clothes in organophosphate poisoning
  • Remove eye contaminants, especially alkalis, acids, and other irritants, by continuous irrigation of the eye with sterile water or normal saline for 15–20 minutes. Analgesic eye drops may be required to perform this adequately.
• Inhalation of poisonous gases: move the patient to fresh air.

Contact the Poisons Information Helpline or nearest hospital for advice.

MEDICINE TREATMENT

Ingested poisons

• Activated charcoal.
  • Administer only when the airway is protected (i.e. patient is fully awake and cooperative, or intubated with a depressed level of consciousness).
  • Administer within 1 hour of ingestion of toxin, unless poison is a substance that delays gastric emptying.

Table 21.12: Activated charcoal for poisoning(s)

Charcoal may be useful if these poisons are taken in toxic dose	Poisons where charcoal is ineffective and should not be given
- carbamazepine, barbiturates, phenytoin - dapsone, quinine - theophylline - salicylates - mushroom poisoning (Amanita phalloides) - slow release preparations - digoxin - beta-blockers - NSAIDs	- ethanol, methanol, ethylene glycol - brake fluid - petroleum products (e.g. petrol or paraffin) - iron salts - lead, mercury, arsenic - lithium - strong acids or alkalis - other corrosive agents (e.g. household detergents)

LoE:IIIb⁴¹

Children:

• Activated charcoal, oral, 1 g/kg mixed as a slurry with water. See dosing table.

Adults:

• Activated charcoal, oral, 50 g (36 level medicine measures) diluted in 100 mL water.
  • When mixing, add a small amount of water to charcoal in a container.
  • Cap and shake container to make a slurry and then dilute further.

Specific poisons and antidotes:

Carbon monoxide poisoning

ICD-10 code: T58 + (X49.99/X69.99/Y19.99)

For hypoxia:

• Oxygen, 100% by non-rebreather mask.

Organophosphate and carbamate poisoning

ICD-10 code: T60.0 + (X48.99/X68.99/Y18.99)

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Note:
Healthcare workers should wear personal protective equipment and all caregivers should avoid having skin contact with the poison or the patient’s bodily fluids e.g. vomitus, faeces. If staff come into contact with body fluids, wash off immediately.

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• Decontamination procedures for the patient should only be done once the patient is fully resuscitated. Remove patient’s clothes and wash the body with soap and water. Place clothes in bags and seal.
• Signs and symptoms of poisoning include:
  • diarrhoea and vomiting
  • weakness
  • hypotension
  • pinpoint pupils
  • bradycardia
  • confusion
  • muscle twitching
  • convulsions
  • coma
  • hypersecretions (hypersalivation, sweating, lacrimation, rhinorrhoea)
  • bronchospasm and bronchorrhoea
• Protect airway if GCS <8.
• Suction secretions frequently.
• Intubate and ventilate if hypoxia, hypercarbia, or decreased respiratory effort.
• Start atropine antidote immediately.

For bronchorrhoea, bronchospasm or bradycardia:

Children:

• Atropine bolus, IV, 0.05 mg/kg/dose. See dosing table.

LoE:IVb⁴²

Adults:

• Atropine bolus, IV, 2 mg

LoE:IIIa⁴³

In both adults and children:

• Reassess after 3–5 minutes for evidence of atropinisation as indicated by reduced bronchial secretions, improvement of oxygenation, and decreased oxygen requirements.
• Give repeated atropine boluses incrementally doubling the dose until adequate clinical response achieved, e.g. 2 mg, 4 mg, 8 mg, 16 mg etc.
  • If no clinical response, give double the dose.
  • If some response, give the same or reduced dose.
• Continue to reassess frequently as additional doses may be required.

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Note:
Refer all patients urgently but only when stable.
Poisoning from all pesticides (i.e. agricultural stock remedies) is a notifiable medical condition. Please visit www.nicd.ac.za for further information.

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Opioid overdose:

ICD-10 code: T40.0-9 + (X42.99/X62.99/Y12.99)

• Respiratory support is the mainstay of treatment. Give naloxone for severe poisoning only (i.e. patients requiring ventilatory support) or as a single test dose for uncertain diagnosis.
  • If respiration adequate, observe the patient in a monitored setting and reassess frequently.
  • If patient is apnoeic or has slow/shallow respirations, assist ventilation with bag-valve mask attached to supplemental oxygen, whilst administering naloxone as described below. If GCS < 8, protect airway and consider intubation if persistent respiratory depression.
• Naloxone, IV (preferable) or IM

	Initial dose (IV/IM)	Repeat dose: Reassess every 2 minutes. If breathing still inadequate, give further naloxone every 2–3 minutes
Children	0.1 mg/kg immediately	Repeat 0.1 mg/kg (maximum 2 mg/dose), up to total dose of 10 mg. LoE:IIIb44
Adult	0.4 mg immediately	Double the dose each time (e.g.: 0.8 mg, 2 mg, 4 mg), up to total dose of 10 mg. LoE:IVb45

• Naloxone has a short duration of action (45 minutes) - continue to monitor closely as further doses of naloxone may be needed while awaiting and during transport.
• In patients addicted to opioids, naloxone may precipitate an acute withdrawal syndrome after several hours. This must not prevent the use of naloxone.
• Refer all patients.

Paracetamol poisoning:  

ICD-10 code: T39.1 + (X40.99/X60.99/Y10.99)

All symptomatic patients or those with a history of significant single ingestion (≥ 200 mg/kg or 10 g, whichever is less) should be referred urgently for paracetamol blood level (taken at least 4 hours post-ingestion) and consideration of N-acetylcysteine.

Where referral is delayed:

• N‐acetylcysteine, oral, 140 mg/kg immediately.
  • Followed by 70 mg/kg 4 hourly, for seventeen doses.

LoE:IIIb⁴⁶

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Note:
- Avoid giving oral N-acetylcysteine together with activated charcoal, as systemic absorption and effect of N-acetylcysteine is reduced.

LoE:IIIb⁴⁷

- Anaphylactoid reactions to N-acetylcysteine do occur and the loading dose should preferably be administered in a monitored area.

LoE:IIIb⁴⁸ 

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Toxic alcohols (ethylene glycol and methanol poisoning)

• Refer all cases
• See Adult Hospital Poisonings - Ethylene glycol poisoning.

REFERRAL

• All intentional overdoses.
• All symptomatic patients.
• All children in whom toxicity can be expected, e.g. ingestion with:
  • paracetamol ≥200 mg/kg or 10 g (whichever is less)
  • anti-epileptics
  • warfarin
  • anticholinergics
  • antihypertensives
  • tricyclic antidepressants
  • sulphonylureas
  • paraffin (unless patient has a normal respiratory rate after 6 hours)
  • iron tablets
  • pesticides

LoE:IVb⁴⁹ 

If in doubt, consult the referral hospital or Poisons Information Helpline.

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Note:
Send the following to hospital with the patient:
- detailed referral letter with all appropriate clinical details. Ensure to include time of ingestion and treatment received.
- a sample of the poison or the empty poison container

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Click here for the pdf.

Click here for the NEMLC Recommendations for medicine amendments (2020-4 review cycle).

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Standard Treatment Guidelines and Essential Medicines List for South Africa, Primary Healthcare, 2020-4_Version 1.1_October 2024

Chapter 21: Emergencies and Injuries