Exposure to poisonous substances

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/ T44.0-9/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)

• Description
• General Measures
• Emergency Management
• Referral

Note: Poisoning from agricultural stock remedies is notifiable.

POISON INFORMATION CENTRES:

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

Signs and symptoms vary according to the nature of poisoning.

GENERAL MEASURES

Emergency Management

• 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. of the suspected agent used to identify poisons involved.
• Document, and respond to, abnormalities of:
  • pulse rate
  • blood pressure
  • respiratory rate
  • level of consciousness
  • pupillary size and reaction
  • oxygenation

Ingested poisons

• 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 normal saline for advice15–20 minutes. Analgesic eye drops may be required to perform this adequately.

EMERGENCY MANAGEMENT

• Inhalation of poisonous gases: move the patient to fresh air.
• Ingested poisons: decontaminate the gut using activated charcoal.

MEDICINE TREATMENT

• Assess patient urgently and perform resuscitation as required. Wear personal protective equipment. Ssee: cardiopulmonary arrest
• Take a history and identify the nature and route of poisoning.
• Remove contaminated clothes in organophosphate poisoning and thoroughly wash off any poison from the skin with soap and water.

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.
  • Children: 1 g/kg mixed as a slurry with water. See dosing table, pg 23.1.
  • Adults: 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.

Protect the airway:

• Place in lateral position if decreased level of consciousness.
• Identify the poison and keep a sample of the poison or container.
• Contact the nearest hospital or Poisons Information Helpline or nearest hospital for advice.

Specific poisons and antidotes

Carbon monoxide poisoning

T58 + (X49.99/X69.99/Y19.99)

For hypoxia:

• Oxygen, 100% by non-rebreather mask.

Organophosphate and carbamate poisoning

T60.0 + (X48.99/X68.99/Y18.99)

• 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.
• 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 closed bags
• Signs and symptoms of organophosphate poisoning include:
  • diarrhoea and vomiting
  • hypotension
  • bradycardia
  • muscle twitching
  • coma
  • hypersecretions (hypersalivation, sweating, lacrimation, rhinorrhoea)
  • brochospasm and bronchorhoea
  • weakness
  • pinpoint pupils
  • confusion
  • convulsions
• 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:

• Atropine, bolus IV
  • Children: 0.05 mg/kg/dose. See dosing table, pg 23.2.
  • Adults: 2 mg

LoE III

LoE:II[i]

Note: Refer all patients urgently but only when stable.

LoEIII [25]

Opioid overdose 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 prescribed below. If GCS < 8, protect airway and consider intubation if persistent respiratory depression.
• Naloxone, IV (preferable) or IM

LoEIII [26]

• 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 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 acetylcysteine.

Where referral is delayed:

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

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

LoE:III[i]

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)
    LoE: III [27]
  • anti-epileptics
  • warfarin
  • anticholinergics
  • antihypertensives
  • tricyclic antidepressants
  • sulphonylureas
  • paraffin (unless patient has a normal respiratory rate after 6 hours)
  • iron tablets

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

Note: Send the following to hospital with the patient:

• written information
• a sample of the poison or the empty poison container