Poisoning

Question 1

What are causes of poisoning?

Answer 1

Accidental in young children
Self harm in older children
Experimentation with recreational substances
Iatrogenic - drug errors 
Intentional - by parents or carers

Question 2

What should be determined in history?

Answer 2

What
How much
When

Other medicines/chemicals kept in same place
Child with any other children?

Question 3

What is management of poisoning?

Answer 3

ABCDE

Consider intubation if GCS < 8 or respiratory failure
If GCS 8-14 consider oral/nasopharyngeal airway and put in recovery position

Maintain BP, correct hypoglycaemia, monitor UO

Blood gas: metabolic acidosis with increased anion gap can be due to metformin, alcohol, ethylene, cyanide, isoniazid, iron, aspirin

Test for paracetamol, ethanol, methanol, ethylene glycol, salicylate, iron, anti-convulsants, lithium, digoxin, theophylline, carboxyhemoglobin if suspected

Supportive management

Determine is specific antidote is available

Question 4

What are specific antidote for beta-blockers?

Answer 4

Atropine for bradycardia: 40micrograms/kg IV
Glucagon 50-150mcg/kg IV + infusion of 50mcg/kg/h in 5% glucose

Consider adrenaline or dopamine infusion

Question 5

What specific antidote for carbon monoxide poisoning?

Answer 5

High flow oxygen to hasten dissociation CO

Mannitol for cerebral oedema

Question 6

What specific antidote for digoxin poisoning?

Answer 6

Atropine for bradycardia: 40micrograms/kg IV

Digoxin specific antibody in those with severe dysrhythmias/hyperkalaemia

Question 7

Specific antidote for opioids?

Answer 7

IV naloxone 10mcg/kg

If no response try 100mcg/kg

Question 8

Specific antidote for methanol/ethylene glycol?

Answer 8

Fomepizole
Inhibits production of toxic metaboliste

Haemodialysis in severe cases

Question 9

Specific antidote for sulfonylureas?

Answer 9

Octreotide

Question 10

Clinical features of opioid poisoning?

Answer 10

E.g. methadone, morphine, codeine, oxycodone, heroin

Bradycardia
Hypotension
Decreased RR
Pin-point pupils

Question 11

Clinical features of cholinergic poisoning

Answer 11

E.g. pilocarpine

Diarrhoea
Urination
Miosis
Bradycardia
Emesis
Lacrimation
Lethargy
Salivation

Question 12

Clinical feature of anticholinergic poisoning?

Answer 12

E.g. tricyclic antidepressants

Tachycardia, drowsiness, dry mouth

Hyperthermia
Faical flushing
Dry skin
Dilated pupils
Delirium

Question 13

Clinical features of sympathomimetic poisoning?

Answer 13

Cocaine, amphetamines,

Tachycardic
Hypertensive
Hyperthermia
Dilated pupils
Sweating

Question 14

Clinical features of button battery ingestion?

Answer 14

Abdominal pain
Gur perforation
Stricture formation

Corrosion of gut wall due to electrical circuit production

Question 15

Management of button battery ingestion?

Answer 15

X-ray of chest and abdomen

Endoscopic removal if in oesophagus, object fails to pass or symptoms are present

Question 16

Clinical features of iron poisoning?

Answer 16

Initial:
Vomiting, diarrhoea, haematemesis, malaena, acute gastric ulceration

Latent period of improvement

6-12h later:
Drowsiness, coma, shock, liver failure with hypoglycaemia, convulsions

Long term: gut strictures

Question 17

Management of iron poisoning?

Answer 17

Serious toxicity if >75mg/kg elemental iron ingested

Serum iron level after 4h ingestion measured

IV Desferoxamine:
Chlates iron
Stop when acidosis improves
Leads to orangey-red urine demonstrating free iron has been bound

Haemofiltration
Endoscopy to remove tablets

Question 18

Feature soft salicylate poisoning? Dose?

Answer 18

Toxicity occurs at 100mg/kg aspirin

Early:
Vomiting
Tinnitus
Hearing loss

Later:
Stimulation of respiratory centres leads to tachypnoea and respiratory alkalosis
This is followed by metabolic acidosis
GI irritation 
Agitation, delirium, seizures

Question 19

Management of salicylate poisoning?

Answer 19

Activated charcoal is effective is adsorbing aspiring within 1h of ingestion
Plasma salicylate concentration 2-4h after ingestion helps to estimate toxicity
Alkalinization of urine increases excretion of salicylates
Haemodialysis also effectively removes salicylate

Question 20

Clinical features of paracetamol poisoning?

Answer 20

Nausea, abdo pain, vomiting
Later (12-24h)
Liver failure, raised hepatic enzymes
Hypoglycaemia, hypotension, encephalopathy, coagulopathy

Question 21

Management of paracetamol overdose

Answer 21

Plasma paracetamol concentration at >4h post ingestion
Venous gas, U&E, FBC, LFT, clotting

If <1h and >150mg/kg of tablets, give activated charcoal
(CI: Redcued GCS, vomiting)

If plasma paracetamol is above treatment line or abnormal INR, ALT or creatinine, give N-acetylcysteine IV NAC

If delayed presentation or staggered ingestion, give NAX immediately

Psychiatric evaluation?