Ethylene glycol toxicity: Difference between revisions
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== Clinical Features == | == Clinical Features == | ||
*Stage 1 - CNS | |||
**30min-12hr after ingestion | |||
**Pt appears intoxicated (slurred speech, ataxia, stupor, seizure, coma) | |||
*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, CVAT | |||
***Hematuria, proteinuria, calcium oxalate crystals (50%) | |||
==Differential Diagnosis== | ==Differential Diagnosis== | ||
| Line 29: | Line 29: | ||
== Diagnosis == | == Diagnosis == | ||
*Chemistry | |||
**Anion gap acidosis | |||
***Will not be present immediately after exposure (only metabolite causes acidosis) | |||
**Renal failure | |||
*Serum Osm | |||
**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 | |||
*Glucose | |||
*Alcohol levels | |||
*UA | |||
**Hematuria, proteinuria, pyuria | |||
**Calcium oxalate crystals (late finding; only seen in 50%) | |||
**Urinary fluorescence (may be seen 6 hours after ingestion) | |||
*Total CK | |||
*VBG | |||
*ECG | |||
**QT prolongation ~ hypocalcemia | |||
*APAP/ASA levels | |||
== Treatment == | == Treatment == | ||
*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 w/ unclear history and osm gap >10 | |||
****Coma or AMS in pt w/ 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 | |||
***BAL of 100-150 completely saturates alcohol dehydrogenase | |||
***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 with bicarbonate | |||
** 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) | |||
*Decrease oxalate production | |||
**Thiamine 100mg IV q6hr x2d | |||
**Pyridoxine 50mg q6hr x2d | |||
**Magnesium 2gm IV x1 | |||
==See Also== | ==See Also== | ||
Revision as of 01:56, 7 June 2015
Background
- Characteristics
- Component of antifreeze
- 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
- Component of antifreeze
- Parent compound causes inebriation; metabolite (glycolic acid) causes toxicity
Clinical Features
- Stage 1 - CNS
- 30min-12hr after ingestion
- Pt appears intoxicated (slurred speech, ataxia, stupor, seizure, coma)
- 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, CVAT
- Hematuria, proteinuria, calcium oxalate crystals (50%)
- 24-72hr after ingestion
Differential Diagnosis
Sedative/hypnotic toxicity
- Absinthe
- Barbiturates
- Benzodiazepines
- Chloral hydrate
- Gamma hydroxybutyrate (GHB)
- Baclofen toxicity
- Opioids
- Toxic alcohols
- Xylazine toxicity
Diagnosis
- Chemistry
- Anion gap acidosis
- Will not be present immediately after exposure (only metabolite causes acidosis)
- Renal failure
- Anion gap acidosis
- Serum Osm
- 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
- Only parent alcohol is osmotically active
- Calculated serum osm - measured serum osm
- Osm gap
- Glucose
- Alcohol levels
- UA
- Hematuria, proteinuria, pyuria
- Calcium oxalate crystals (late finding; only seen in 50%)
- Urinary fluorescence (may be seen 6 hours after ingestion)
- Total CK
- VBG
- ECG
- QT prolongation ~ hypocalcemia
- APAP/ASA levels
Treatment
- 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 w/ unclear history and osm gap >10
- Coma or AMS in pt w/ 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
- Indications:
- Ethanol
- BAL of 100-150 completely saturates alcohol dehydrogenase
- 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
- Fomepizole
- Correction of metabolic acidosis with bicarbonate
- 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
- Bicarbonate 1-2mEq/kg IV bolus to attain pH = 7.45-7.50
- 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)
- Indications:
- Decrease oxalate production
- Thiamine 100mg IV q6hr x2d
- Pyridoxine 50mg q6hr x2d
- Magnesium 2gm IV x1