Ethylene glycol toxicity: Difference between revisions
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== Background == | == Background == | ||
*Component of antifreeze, automobile coolants, de-icing agents, industrial solvents and hydraulic brake fluid. | |||
**Fluoresces yellow/green under Wood's lamp (neither Sn nor Sp) | |||
*Sweet taste | |||
*Lethal dose = 1g/kg | |||
**Volume depends on percentage of ethylene glycol in solution, typically 0.6 g/mL | |||
**60 kg patient lethal dose ~ 100 mL | |||
*Parent compound causes inebriation; metabolite (glycolic acid) causes toxicity | *Parent compound causes inebriation; metabolite (glycolic acid) causes toxicity | ||
[[File:toxic alcohol ingestion - ethylene glycol.JPG|thumbnail]] | [[File:toxic alcohol ingestion - ethylene glycol.JPG|thumbnail]] | ||
== Clinical Features == | ==Clinical Features== | ||
===Stage 1 - CNS=== | ===Stage 1 - CNS=== | ||
*30min-12hr after ingestion | *30min-12hr after ingestion | ||
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{{Sedatve/hypnotic toxicity types}} | {{Sedatve/hypnotic toxicity types}} | ||
== Diagnosis == | ==Diagnosis== | ||
===Chemistry=== | ===Chemistry=== | ||
May see: | May see: | ||
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*Useful to discern the cause of the anion gap as well as assess for other toxic ingestion | *Useful to discern the cause of the anion gap as well as assess for other toxic ingestion | ||
== | ==Management== | ||
===ADH enzyme blockade=== | ===ADH enzyme blockade=== | ||
'''Fomepizole:''' | '''Fomepizole:''' | ||
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*[[Sedative/hypnotic toxicity]] | *[[Sedative/hypnotic toxicity]] | ||
== References == | ==References== | ||
<references/> | <references/> | ||
[[Category:Tox]] | [[Category:Tox]] | ||
Revision as of 06:10, 23 February 2016
Background
- Component of antifreeze, automobile coolants, de-icing agents, industrial solvents and hydraulic brake fluid.
- Fluoresces yellow/green under Wood's lamp (neither Sn nor Sp)
- Sweet taste
- Lethal dose = 1g/kg
- Volume depends on percentage of ethylene glycol in solution, typically 0.6 g/mL
- 60 kg patient lethal dose ~ 100 mL
- Parent compound causes inebriation; metabolite (glycolic acid) causes toxicity
Clinical Features
Stage 1 - CNS
Stage 2 - Cardiopulmonary
- 12-24hr after ingestion
- Most deaths occur during this stage
- Hypertension, tachycardia, CHF
- ARDS, pulmonary infiltrates
- Hypocalcemia (chelation by oxalate)
- Myositis & CK elevation
Stage 3 - Renal
- 24-72hr after ingestion
- Flank pain, CVA tenderness
- Hematuria, proteinuria, calcium oxalate crystals (50%)
Differential Diagnosis
Sedative/hypnotic toxicity
- Absinthe
- Barbiturates
- Benzodiazepines
- Chloral hydrate
- Gamma hydroxybutyrate (GHB)
- Baclofen toxicity
- Opioids
- Toxic alcohols
- Xylazine toxicity
Diagnosis
Chemistry
May see:
- Anion gap acidosis
- Will not be present immediately after exposure (only metabolite causes acidosis)
- Renal failure
- Glucose - may be low in setting of decreased caloric intake
Serum osmolality
Osm gap:
- Calculated serum osm - measured serum osm
- Calculated serum osm = 2Na + BUN/2.8 + glucose/18 + ethanol/4.2)
- Normal < 10
- >50 highly suggestive of toxic alcohol poisoning)
Note: Cannot rule out toxic ingestion with a "normal" osmol gap
- Only parent alcohol is osmotically active
- Delayed presentation may mean that much of it is already metabolized
Alcohol levels
May be useful however even if elevated, patients can still have ingested a toxic alcohol
Urinalysis
- Hematuria, proteinuria, pyuria
- Calcium oxalate crystals (late finding; only seen in 50%)
- Urinary fluorescence (may be seen 6 hours after ingestion)
Total CK
Useful to assess for signs of rhabdomyolysis especially if the patient was found laying down
Venous blood gas
Needed to assess degree of acidosis. An ABG is not necessary since pH can be approximated with a clinical degree via a VBG
ECG
Acetaminophen or Aspirin levels
- Useful to discern the cause of the anion gap as well as assess for other toxic ingestion
Management
ADH enzyme blockade
Fomepizole:
- Indications:
- Ethylene glycol level >20mg/dL
- Suspected significant ethylene glycol ingestion w/ ETOH level <100mg/dL
- Coma or AMS in pt with unclear history and osm gap >10
- Coma or AMS in pt with unclear history and unexplained met acidosis and ETOH level <100
- Dosing
- 15mg/kg IV over 30min; follow by 10mg/kg q12hr until level <20 or acidosis resolves
Ethanol:
- Ethanol drips are rarely used
- BAL of 100-150 completely saturates alcohol dehydrogenase
- Dosing:
- IV: load 800mg/kg; then give 100mg/kg/hr
- Oral: 3-4 1-oz "shots" of 80-proof liquor); then give 1-2 "shots" per hour
Correction of metabolic acidosis
Bicarbonate infusion is an option however the patient will need to compensate with an increased respiratory rate otherwise a concomitant respiratory acidosis will ensure.
- Bicarbonate 1-2mEq/kg IV bolus to attain pH = 7.45-7.50
- Follow by infusion of 150mEq/L in D5 @ 1.5-2 times maintenance fluid rate
- Monitor for worsening hypocalcemia
Dialysis
- Indications:
- Refractory metabolic acidosis (pH <7.25) w/ AG >30
- Renal insufficiency
- Deteriorating vital signs despite aggressive supportive care
- Electrolyte abnormalities refractory to conventional therapy
- Ethylene glycol level >50mg/dL (controversial)
- Glycolic acid level > 8 mmol/L (glycolic acid is metabolite that causes anion gap acidosis)
Decrease oxalate production
- Thiamine 100mg IV q6hr x2d
- Pyridoxine 50mg q6hr x2d
- Magnesium 2gm IV x1