Toxicology talk

Dr Ian Turner FACEM

Toxicology

› Approach to the tox patient› Common toxidromes› Important antidotes

In an hour

› 19 F› Brought to ED by parents after ingestion of packet of Panadol

tablets after night out drinking with friends› Normal vitals › What to you do?

Case

› Resuscitation

› Risk assessment

› Supportive care

› Investigations – BSL, ECG, paracetamol, VBG

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOXICOLOGY

› History

› Examination

› Investigations

› Treatment

TRADITIONAL

Approach

› Probably none

› Time, type, amount, co-ingestants, symptoms

› Anti-emetics, fluids

› BSL, ECG, paracetamol level (when)

› Charcoal?

› Can you speed the transit, do you need to?

› NAC

› Medical, psychiatric, social factors

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case

› Unknown ETOH› Empty box of Panamax – 100 tablet box, 500mg tablets› WCS = 100 x 500mg = 50g paracetamol› Patient wt = 60kg 50g/60kg = 833mg/kg› Ingestion 11pm› Seen in ED at 1:30am› Feels well› Soft abdo

Risk Assessment

› Usually at risk if >150mg/kg consumption (acute)› ETOH impact?

Is she at risk?

› Not routine› Not routine› Yes – this is not a screen

4 hours unless delayed presentation

› LFTs› Coags› Paracetamol

Investigations

› No

› Too late; ETOH gives risk of ACS

› No

› Time consuming and risky

INDICATED?

› Ipepac

› Charcoal

› Gastric lavage

› Whole bowel irrigation

OPTIONS

Decontamination

› No

› No

› No

INDICATED?

› MDAC

› Urinary alkalinisation

› Haemodialysis and other extracorporeal

OPTIONS

Enhanced Elimination

› N-acetylcysteine› NAPQI increases with paracetamol ingestion› NAPQI damages liver› Glutathione conjugates NAPQI› Too much NAPQI run out of glutathione› N-AC replenishes glutathione

Antidote

› How much and when› 4-hour paracetamol level› Nomogram

N-AC

› How much and when› 4-hour paracetamol level› Nomogram› Above line – start infusion as per protocol

N-AC

› 150mg/kg in 200mL 5% glucose

› 50mg/kg in 500mL 5% glucose

› 100mg/kg in 1000mL 5% glucose

DOSE

› 15-60 mins

› 4 hours

› 16 hours

TIME

N-AC: 3-stage infusion

› N-AC completed; sober

› Risk assessment

› Supports

INTERVENTION

› Medical

› Psychiatric

› Social

FACTORS

Disposition

› Delayed presentation› Slow-release formulations› Staggered ingestions

Different scenarios

› 23 M (70kg) – 2 packs of Panadol 2 hours ago› 14 F (40kg)– 24 Panadeine Forte tablets 6 hours ago› 38 M (85kg) – 2 Panamax tablets every 2 hours for 2 days› 56 F (50kg) – drunk, half pack of Panadol Osteo next to her,

last seen 2 hours prior

Paracetamol Cases

› Use within 1 hour› GCS 15 and expect to remain so› Don’t use if not a toxic level ingestion› Doesn’t bind metals or alcohols or acids/alkalis

Charcoal

› 27 M BIBA› Ingested pack of Endep 1 hour ago› Alert› HR 105, BP 120/80, RR 20, SaO2 100%, afeb

Case 2

› Not yet› >10mg/kg potentially life-threatening› Anti-emetics, fluids, monitoring› ECG, paracetamol, VBG

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 2

› Not yet

› >10mg/kg potentially life-threatening

› Anti-emetics, fluids, monitoring

› ECG, paracetamol, VBG

› Possibly charcoal

› No

› NaHCO3, hyperventilate

› Medical, psychiatric, social factors

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 2

› 23 M backpacker brought to ED by friends following deliberate ingestion of headache tablets

› Feels dizzy, short of breath, and anxious› Afeb, HR 90, BP 125/87, RR 25, SaO2 100%

Case 3

› Not yet› Unknown› Anti-emetics, fluids, monitoring› ECG, paracetamol

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 3

› Not yet› Unknown› Anti-emetics, fluids, monitoring› ECG, paracetamol, ABG

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 3

› Acidaemia

› Respiratory alkalosis

› Metabolic acidosis

› AG = (138 + 3.2) – (10 + 108) = 23.2

› What headache tablets could cause this?

› Salicylate = 6.2mmol/L

INTERPRETATION

› pH – 7.32

› CO2 – 17

› HCO3- – 10

› O2 – 125

› Na+ – 138

› K+ – 3.2

› Cl- – 108

ABG

Case 3

› Not yet

› Unknown

› Anti-emetics, fluids, monitoring

› ECG, paracetamol, VBG

› Charcoal

› Urinary alkalinisation, dialysis

› None

› Medical, psychiatric, social factors

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 3

› 53 M Russian sailor retrieved to your ED from cargo ship with altered conscious state

› Now GCS 3

Case 4

› Intubate and ventilate› No useful history› Fluids, monitoring› ECG, paracetamol, ABG

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 4

› Intubate and ventilate› No useful history› Fluids, monitoring› ECG, paracetamol, ABG

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 4

› Acidaemia

› Respiratory alkalosis

› Metabolic acidosis

› AG = (144 + 4.0) – (8.2 + 102) = 37.8

› OSM (calc) = 2Na + Ur + BSL + ETOH = 305.8

› OSM Gap = 324 – 305.8 = 18.2

› HAMGA and raised OSM Gap = toxic alcohol

› Methanol, ethylene glycol, isopropanolol

INTERPRETATION› pH – 7.12

› CO2 – 26

› HCO3- – 8.2

› Na+ – 144

› K+ – 4.0

› Cl- – 102

› Ur – 6.4

› Cr – 152

› Glucose – 5

› OSM - 324

ABG + BIOCHEM

Case 4

› Intubate and ventilate

› No useful history

› Fluids, monitoring

› ECG, paracetamol, ABG

› No

› Dialysis

› ETOH (fomepizole not avail)

› ICU

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 4

› 17 M brought by parents with confusion, agitation, and sweats› Has been out with friends all evening› No known ingestions› Picking at clothes, the bed, and the air› Looks uncomfortable› 37.8C, HR 130, BP 97/65, GCS 14 (M6, V4, E4), dilated pupils

Case 5

› Sedation

› Exam findings

› Fluids, monitoring

› ECG, paracetamol

› No clear indication

› None

› Physostigmine

› Resolution symptoms

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 5

› Sympathomimetic› Anticholinergic› Cholinergic› Opioid› Hypnosedative› Serotonergic

Toxidromes

› 28 F dumped at front of ED, GCS 3› RR 4, SaO2 89%› HR 100, BP 95/60› GCS 3› Pin-point pupils› Tract marks› No other signs trauma

Case 6

› Airway support› Exam findings› Fluids, monitoring› BSL, ECG, paracetamol› No › No› Naloxone

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 6

› Opioid naïve200mcg to 400mcg

› Opioid tolerantsmall boluses1 ampoule (400mcg/mL) into 9mL N. saline40mcg/mlSlow push

› Infusion5 ampoules in 500mL N. saline 25-100mL/hr

› Options if no IV access?

Naloxone dosing

› Airway support› Exam findings› Fluids, monitoring› BSL, ECG, paracetamol› No › No› Naloxone› Resolution of symptoms and observation

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 6

› 21 M brought to ED by police, handcuffed, agitated› Friends told police patient using bath salts› Aggressive, yelling› 37.6C, HR 130, BP 150/90, RR 24, SaO2 100%, GCS 15› Flushed skin with cool peripheries› Dilated pupils

Case 7

› Sedation, restraint› Identifying bath salts, exam findings› Fluids, monitoring› BSL, ECG, paracetamol

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 7

› Sedation, restraint

› Exam findings

› Fluids, monitoring

› BSL, ECG, paracetamol

› No

› No

› No

› Resolution of symptoms

TOXICOLOGY› Resuscitation

› Risk assessment

› Supportive care

› Investigations

› Decontamination

› Enhanced elimination

› Antidotes

› Disposition

TOX APPROACH

Case 7

› Vitamin K› Atropine, pralidoxime› Desferrioxime

› NaHCO3, intralipid› Glucagon, HIET› Pyridoxime› Calcium, HIET

› Warfarin› Organophosphates› Iron› Local anaesthetic› Beta-blockers› Isoniazid› Verapamil

Antidote quiz

› Thiosulphate, hydrocobalamin› Methylene blue› ETOH› Calcium› Cyproheptadine

› Cyanide› Methaemoglobinaemia› Methanol› Hydrofluoric acid› SSRIs

Antidote quiz