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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