Recognition of Poisoning ✅ Flashcards
Describe the age distribution of poisoning?
Bimodal - young children under 5, and adolescents/young adults
Why are young children under 5 at higher risk of poisoning?
They are curious, explore their environment using all their senses, and are particularly prone to putting things in their mouths. They also lack a sense of danger
Why are adolescents/young adults at high risk of poisoning?
- Deliberate ingestion of substances from deliberate self harm
- Result of exploratory behaviour with recreational drugs
What substances are most commonly ingested by young children?
Those directly accessible in their own environment, e.g. household products such as bleach, OTC medications
What substances are most commonly ingested in deliberate self harm?
Paracetamol and ibuprofen
Other than ingestion, how can poisoning occur?
- Dermal exposure
- Inhalation
What is true of the majority of children and young people attending healthcare provision for potential poisoning?
They suffer little in the way of adverse effects, and do not require active management
Give 9 examples of medications that can be fatal in small doses (1-2 tablets) to children weighing <10kg
- Tricyclic antidepressants
- Antimalarials
- Beta blockers
- Calcium channel antagonists
- Oral hypoglycaemics
- Opioids
- Antiarrhythmics
- Theophylline
- Clozapine
How is unintentional harm from potentially very dangerous medicines prevented?
Safe storage
How do the majority of children and young people with suspected poisoning present?
With a clear history of potentially toxic exposure
How might toxic exposure be detected in young children?
They are usually found in possession of a packet of tablets, bottle of medicine, or household cleaning product
How might toxic exposure be detected in attempt at deliberate self harm?
Young people frequency admit ingestion to a third party, often a relative or friend
How is management of suspected poisoning guided
Risk assessment of potential harm
What factors are taken into account when assessing the risk of toxic ingestion?
- Toxicity of substance
- Toxicity of co-ingested substances
- Dose ingested and reliability of history
- Presence of symptoms
- Time since ingestion
- Other co-morbidities
In what situations might the substance responsible for poisoning be unclear?
- Unwillingness of patient to reveal what they have ingested
- Patient doesn’t know what they have ingested
What might identify the causative agent when a patient doesn’t know/is unwilling to disclose what substance they have ingested?
- Careful questioning of the family and friends
- Search of patients clothing
- Physical examination
- Lab tests
What is meant by ‘toxidrome’?
The combination of physical findings that result from excessive effect of specific classes of drugs
What are toxidrome useful for?
Narrowing down the diagnosis
What is the limitation of toxidromes?
Physical findings can be confounded by co-ingestion of other medications and inter-individual variability
What are the types of poisoning described in toxidromes?
- Anticholinergic
- Cholinergic
- Hallucinogenic
- Opioid
- Sedative/hypnotic
- Sympathomimetic
What are the common agents causing anticholinergic poisoning?
- Anti-histamines
- Tricyclic antidepressants
- Carbamazepine
- Phenothiazines
What are the signs and symptoms associated with anticholinergic poisoning?
- Tachycardia
- Hyperthermia
- Mydriasis
- Warm and dry skin
- Urinary retention
- Agitation
What are the common agents causing cholinergic poisoning?
- Carbamates
- Organophosphate insecticides
- Some mushrooms
What are the signs and symptoms of cholinergic poisoning?
- Salivation
- Lacrimation
- Urination
- Diarrhoea
- Bronchorrhoea
- Bronchospasm
- Bradycardia
- Vomiting
What are the common agents causing hallucinogenic poisoning?
- Amphetamines
- Cocaine
- MDMA (ecstasy)
What are the signs and symptoms of hallucinogenic poisoning?
- Hallucinations
- Panic
- Seizures
- Hypertension
- Tachycardia
- Tachypnoea
What are the common agents causing opioid poisoning?
- Morphine
- Codeine
- Methadone
What are the signs and symptoms of opioid poisoning?
- Hypoventilation
- Hypotension
- Miosis
- Sedation
- Bradycardia
What are the common agents causing sedative/hypnotic poisoning?
- Anticonvulsants
- Benzodiazepines
- Ethanol
What are the signs and symptoms of sedative/hypnotic poisoning?
- Ataxia
- Blurred vision
- Sedation
- Hallucinations
- Slurred speech
- Nystagmus
What are the common agents causing sympathomimetic poisoning?
- Cocaine
- Amphetamines
- MDMA
What are the signs and symptoms of sympathomimetic poisoning?
- Tachycardia
- Hypertension
- Mydriasis
- Agitation
- Seizures
- Hyperthermia
- Diaphoresis
What is the limitation of lab tests when determining the causative agent in poisoning?
There are few specific lab tests that add significantly to thorough history and examination
What lab tests may be useful when determining the causative agent in poisoning?
- Quantitive serum drug assays (if rapidly available)
What drugs in particular might quantitative serum assays be useful for?
- Paracetamol
- Salicylate
- Iron
- Digoxin
When might blood gas analysis be useful in the management of a suspected poisoning patient?
- When considering poisoning as a cause of an unusual presentation or in a patient with a reduced conscious level
- To assess poisoning severity for certain more dangerous substances
What should be done if a metabolic acidosis is present on blood gas in a suspected poisoning patient?
The anion gap should be calculated
What is the formula for calculating anion gap?
( Na + K ) - ( Cl - HCO3)
What is considered to be an abnormal anion gap?
> 16mmol/L
What does a high anion gap indicate?
Elevated serum concentration of anions, resulting in a loss of buffering HCO3 to maintain electroneutrality
What are the causes of a metabolic acidosis with a raised anion gap?
- Methanol
- Urhaemia
- Diabetic ketoacidosis
- Propylene glycol
- Iron and Isoniazid
- Lactic acidosis
- Ethylene glycol
- Salicylates
What acronym can be used to remember the causes of a metabolic acidosis with raised anion gap?
MUDPILES
What is the limitation of toxicological screens of urine and blood in the management of suspected poisoning?
They typically test for drugs of abuse and, without clinical suspicion or known access to illicit drugs, they are not useful for guiding acute treatment
When might toxicological screens of urine and blood be of use in suspected poisoning?
May provide forensic evidence indicating safeguarding concerns
What is essential when obtaining urine and blood toxicological screens for forensic evidence?
‘Chain of evidence’ procedures are followed when transferring samples to the laboratory
