Poisoning - Overview

Disclaimer

These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline. 

Read the full PCH Emergency Department disclaimer.

Aim 

To guide PCH ED staff with the assessment and management of poisoning or overdose in children.

This guideline provides an outline of the general approach to poisoning. Specific information about poisoning presentations can be obtained from Poisons Information: 13 11 26 or refer to the Toxicology Handbook.

Background

  • The vast majority of morbidity and mortality in toxicology arises from complication of the poisoning not the poisoning itself, particularly aspiration due to sedation
  • Good supportive care is the best way to prevent this
  • Poisonings follow a highly predictable path
  • Risk assessment is an essential cognitive step during assessment that outlines ongoing care
  • If information is unclear always base the risk assessment upon a 'worse case scenario'
  • Know your list of '2 pills can kill' in a toddler
    • Most accidental paediatric ingestions are only 1-2 tablets and a risk assessment will be low. Nevertheless, there are some toxins which can kill a young child with a very small exposure. These should be aggressively managed with early senior advice and/or toxicology service input.

The general approach to all poisonings should follow the RRSIDEAD format

R Resuscitation
R Risk Assessment
S Supportive Care
Investigations
D Decontamination
E Enhanced Elimination
A Antidotes
D Disposition

Management

Resuscitation

Follow traditional ABC approach with modification

  • Airway
  • Breathing
  • Circulation
  • Control/Correct
    • Seizures with midazolam (phenytoin contraindicated)
    • Hypothermia
    • Hyperthermia
      • Temperature > 38.5º requires core monitoring
      • Temperature > 39.5° is an indication for intubation, ventilation and paralysis.

Risk assessment

The following five factors will provide an accurate prediction of clinical course, potential complications and time coarse of poisoning to direct management.

  • Agent/s
  • Dose
  • Time of ingestion
    • Use the latest possible time if uncertain
  • Patient factors
    • Weight
    • Comorbidities that may affect prognosis, for example:
      • Heart disease complicating calcium channel overdose
      • Morbid obesity affecting airway patency
  • Clinical status (features and progress)
    • Agents commonly affect the autonomic, central nervous system (CNS) and neuromuscular systems and may produce a recognisable 'toxidrome'
    • Does the clinical presentation of the patient fit with the predictable profile of the overdose?
    Anticholinergic Sympathomimetic Serotonergic 
Examples   Antihistamines
Antidepressants
Antipsychotics
Oxybutinin
Street amphetamines
Dexamphetamine
Methylphenidate
SSRIs/SNRIs
TCAs
MAOi
MNDA
Autonomic Vital Signs  Elevated Elevated Elevated
  Temperature  Elevated
Elevated
Elevated 
  Pupils Dilated Dilated
Dilated
  Skin/mucous membranes  Flushed, dry Flushed, sweaty Flushed, sweaty
CNS Mental status Agitated, delirium Euphoria, agitated Agitated, coma
  Seizures Rarely Yes Yes
Neuromuscular  Tone Normal Increased/rigidity Increased/rigidity
  Reflexes Normal Hyperreflexic Hyperreflexic/clonus
Complications   Urinary retention
Hyperthermia
Rhabdomyolysis
Injury to self
Severe hypertension
Myocardial infarction
Pulmonary oedema
Rhabdomyolysis
Hyponatraemia
Subarachnoid haemorrhage
Hyperthermia
Rhabdomyolysis

Supportive care and monitoring

  • Supportive care is tailored to the risk assessment and may involve:
    • IV hydration
    • Control of agitation and seizures with titrated benzodiazepines
    • Ensuring normoglycaemia
    • Bladder care (especially monitoring for urinary retention).

Investigations

Investigations are done for either specific purposes, to identify occult overdoses, or specific tests to determine the presence or level of a known ingestant.

Screening

  • 12 lead ECG
    • Wide QRS (sodium channel blockade)
    • Long QT (potassium channel blockade, anti-psychotic overdose)
    • Heart blocks (calcium channel and beta blockers/calcium channel poisoning
  • Serum Paracetamol level (4 hours)
  • Blood glucose level (BGL).

Specific

  • Drug levels
    • Paracetamol (in known ingestion)
    • Iron
    • Alcohols
    • Lithium
    • Salicylate
    • Theophylline
    • Anti-epileptics
    • Others

Other adjunctive tests as indicated

  • Blood gas:
    • High anion gap metabolic acidosis
      • TCA
      • Salicylates (late)
      • Iron
      • Toxic alcohol
      • Metformin
    • Respiratory alkalosis
      • Salicylates
    • Respiratory acidosis
      • Sedatives.

  • Abdominal X-ray:
    • Confirmation of iron or other heavy metal ingestion.
  • Blood tests:
    • LFT (delayed paracetamol)
    • UEC
    • INR (Warfarin, delayed paracetamol).

Decontamination

  • Consider but rarely required
    • Activated charcoal
      • Will not bind to hydrocarbons or alcohol, corrosives and metals
      • Reserved for life threatening intoxications in which other measures are not expected to result in a good outcome
      • Contraindicated in un-intubated patient if decreased conscious level, vomiting or seizures are expected
      • Can be considered where the toxin is likely to remain in the gastrointestinal tract (generally within the first hour post ingestion for most agents)
    • Other methods: e.g. whole bowel irrigation - should not be instigated in the ED and should only be commenced on advice of Poisons Information.

Enhanced elimination

  • Consider but rarely required
    • Techniques include: multiple dose activated charcoal, urinary alkalinisation, haemodialysis, haemofiltration, charcoal haemoperfusion.

Antidotes

  • The risk assessment should determine if the potential benefit outweighs the possible adverse effects of the antidote.
Antidote Poison
N-acetylcysteine Paracetamol
Naloxone Opiates
Flumazenil Benzodiazapines
Desferrioxamine Iron
Sodium Bicarbonate Tricyclic antidepressants (TCA)

Disposition

  • The disposition will be determined by:
    • The clinical risk assessment of the overdose
    • The psychiatric safety of the patient (for deliberate overdoses)
    • Other safety factors (parental neglect or drug use, domestic issues)
  • Children should not be discharged home at night unless the risk assessment determines that the overdose is trivial and not requiring any form of observation.

Discharge home with parental supervision

  • Trivial overdose with no requirement for observation
  • Ensure safety issues such as accessibility to tablets are addressed and provide parents with Kidsafe WA Poisoning Fact Sheet
  • Low risk overdose with minimal potential for deterioration during day-time hours
  • Parents must be able to return to ED in the event of deterioration.

Emergency Short Stay Unit

  • Stable patient with low-risk overdose requiring observation
  • Low risk overdose with minimal potential for deterioration during night hours.

Medical ward

  • Stable patient requiring medical or antidote therapy
  • Any suspicion of non-accidental injury (NAI)

PCCU

  • Unstable or intubated patient

Psychiatric ward

  • Medically cleared patient deemed at risk of deliberate self harm

Nursing

  • Baseline observations include heart rate, respiratory rate, oxygen saturation, blood pressure and neurological observations
  • Minimum of hourly observations should be recorded whilst in the emergency department
    • Any significant changes should be reported immediately to the medical team
  • Nursing care specific to the presentation.

Two Tablets - Potentially Lethal to a 10kg Child2

Agent

Principle features of severe toxicity

Amphetamines

  • Amphetamine

  • Metamphetamine

  • MDMA (ecstacy)

Agitation
Confusion
Hypertension
Hyperthermia

Baclofen

Coma

Calcium Channel Blockers

  • Diltiazem CD

  • Verapamil SR

Delayed onset of bradycardia
Hypotension
Conduction defects
Refractory shock

Chloroquine
Hydrochloroquine

Rapid onset of coma
Seizures
Cardiovascular collapse

Dextropropoxyphene

Ventricular tachycardia

Opioids

  • Oxycodone

  • Methadone

  • Morphine Sulphate

  • Diphenoxylate/Atropine

Coma, respiratory arrest
Note: May be delayed with diphenoxylate/atropine and controlled release morphine

Propranolol

Coma
Seizures
Ventricular tachycardia
Hypoglycaemia

Sulfonylureas

  • Glibenclamide

  • Glibenclamide/Metformin

  • Gliclazide

  • Glimepiride

Hypoglycaemia
Note: Onset may be delayed up to eight hours.

Theophylline

Seizures
Supraventricular tachycardia
Vomiting

Tricyclic antidepressants

  • Dothiepin

Coma
Seizures
Hypotension
Ventricular tachycardia

Venlafaxine XR

Seizures


Non-pharmaceutical agents considered potentially lethal to children2

Agent Dose of concern for 10 kg child Clinical effects
Organophosphate and carbamate insecticides
Single sip

Cholinergic symptoms
Seizures
Depressed level of consciousness

Paraquat/Diquat Sip Oro-pharyngeal burns
Multiple organ failure
Pulmonary fibrosis

Hydrocarbons

  • Solvents
  • Eucalyptus oil
  • Kerosene
Sip Rapid depressed level of consciousness
Seizures
Aspiration pneumonia
Camphor

5mL of 100%

Rapid depressed level of consciousness
Seizures
Hypotension

Corrosives

  • Sodium hydroxide
  • Strong acids
  Gastro-oesophageal injury including perforation
Naphthalene

One mothball

NB: Most mothballs contain paradichlorbenzene, which is non-toxic after a single accidental ingestion
Methaemoglobinaemia
Haemolysis
Strychnine
  Rapid onset of generalised muscle spasm
Death by respiratory failure

Bibliography

  1. Murray L, Daly F, Little M, Cadogan M (2011) Toxicology Handbook, 2nd Edition, Elsevier Australia
  2. Murray L, Little M, Pascu O and Hoggett KA (2015) Chapter 2.23 Poisoning in Children, Toxicology Handbook, 3rd Edition, Elsevier Ltd
  3. McCoubrie D, Murray L, Daly FFS and Little M. Toxicology case of the month: ingestion of two unidentified tablets by a toddler. Emerg Medicine J 2006; 23: 718-720
  4. Bar-Oz B, Levichek Z and Koren G. Medications That Can Be Fatal For a toddler with One Tablet or Teaspoon. Paediatric Drugs 2004; 6 (2): 123-126

Endorsed by:  Director, Emergency Department  Date:  Mar 2018


 Review date:   Mar 2021


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