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Case Report. 15 year-old, previously healthy boy19:00 Drank 250ml of antifreeze, ribena and sugar07:00 Awoke feeling
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3. In emergency department... GCS 13/15 (E3, V4, M6)
RR 28/min, Sats 96% on air
HR 80, BP 103/73
Confessed to drinking antifreeze
4. Initial Investigations
5. Pre-ITU Treatment Naloxone 400mcg (ambulance crew)
N-Acetyl Cysteine loading dose
Ethanol 10%, 375ml IV
Sodium Bicarbonate 50mmol IV
No attempts made to reduce toxin absorption
No cardiovascular or respiratory support required
Ethylene Glycol levels taken and sent to Guys Poisons
6. On Transfer to PICU CVVHDF started: exchange 4.5l/hr
Ethanol 10% infusion: target 100mg/dl
6 hourly biochemistry and 2 hourly ethanol levels
Required no further organ support
Further investigations...
7.
8. Outcome Day 5: discharged from PICU
Day 5: converted to intermittent HD (3x per week)
Day 9: off dialysis
Day 12: discharged home
1 year later: discharged from renal clinic
9. About Ethylene Glycol... Chemical name 1,2-Ethanediol
An alcohol (contains CHOH)
Used due to its low freezing point (60% sol: -55oC)
10. ...About Ethylene Glycol Clear, viscous fluid
Sweet taste
Concentrated antifreeze 80-100% by volume
Often dyed blue
12.
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14. Toxicity Toxic quantities only likely through ingestion
Antidote required if >0.15g/kg ingested
Adult fatal dose around 100g pure Ethylene Glycol (approx 100ml concentrated antifreeze)1
Rapid gut absorption
Peak concentrations 1-4 hrs after ingestion1
Usually zero-order metabolism
Almost all toxicity is from metabolites2
15.
17. Early Features (30 min- 12 hrs) Intoxication without alcohol odour
Nausea, vomiting, haematemesis
Seizures and cranial nerve palsies
High osmolar gap
Developing metabolic acidosis
18. Intermediate Features (12- 24 hrs) Osmolar gap normalised
Severe metabolic acidosis from glycolate metabolite (large anion gap)
High lactate on ABG may be artefact or genuine
Pulmonary oedema
Congestive cardiac failure
19. Late Features (24-72 hrs) Acute tubular necrosis
Hypocalcaemia (from oxalate binding)
Calcium oxalate crystalluria
Multi-organ failure
20. Treatment... General Measures
Ethylene glycol levels not available quickly
Support CNS and respiratory depression
Treat any mixed overdose
Prevention of absorption
Gastric aspiration only works within 1st hour
Activated charcoal ineffective
21. ...Treatment Prevention of Metabolism
Ethanol
Fomepizole
Removal of Toxins
Patients kidneys
Haemodialysis/ Haemofiltration
Treatment of Biochemical Abnormalities
Sodium bicarbonate in severe acidosis
Avoid treating mild/moderate hypocalcaemia
22. Ethanol Competes with Ethylene Glycol for Alcohol Dehydrogenase
Load 600-800mg/kg (3 double G&Ts); aim 100-150 mg/100ml
Pros
Cheap and always available (oral/NG if not IV)
More widely used than Fomepizole in UK
Cons
Narrow therapeutic index
Risks CNS depression, hypoglycaemia & pancreatitis
Need frequent plasma levels and ITU/HDU care
23. Fomepizole (4-methylpyrazole) Competitive Alcohol Dehydrogenase inhibitor
15mg/kg load (IV or oral)
Pros
Wide therapeutic index: level monitoring not required
Few side effects (headache, nausea, dizziness)3,4
Evidence of successful treatment without HD/HF5
Cons
Expensive to stock and to use 1,000 per box
No prospective study comparing against ethanol
Not widely available in UK
25. Renal replacement therapy Removes Ethylene Glycol and metabolites
Treats metabolic acidosis
Supports acute kidney injury
Considerations
Antidotes require dose-adjustment
May be unnecessary in patients with normal renal function at presentation treated with Fomepizole (but only case reports and one, small, possibly biased, prospective study)4,6
26. Whats Available to Us? Ethylene Glycol levels processed during working hours at Guys Hospital
Fomepizole not stocked in Wessex- specially imported to the UK; possibly available from Guys
10% Ethanol stocked in most hospitals
Usually an off-licence nearby
Ethanol levels available out-of hours in most hospitals (but may not be automated)
Plenty of beds in ITU for RRT?
27. My Conclusions Important not to delay treatment
Low threshold for ethanol load in ED based on history, ABGs or osmolality
Use HD/HF in all significant cases of poisoning
Case for Fomepizole not completely proven but Id use it if available
28. Any Questions?
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