Ethylene glycol toxicity: Difference between revisions

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#**Electrolyte abnormalities refractory to conventional therapy
#**Electrolyte abnormalities refractory to conventional therapy
#**Ethylene glycol level >50mg/dL (controversial)
#**Ethylene glycol level >50mg/dL (controversial)
#**Glycolic acid level > 8 mmol/L (glycolic acid is metabolite that causes anion gap acidosis)
#Decrease oxalate production
#Decrease oxalate production
#*[[Thiamine]] 100mg IV q6hr x2d
#*[[Thiamine]] 100mg IV q6hr x2d

Revision as of 14:10, 15 October 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
  • Parent compound causes inebriation; metabolite (glycolic acid) causes toxicity

Clinical Features

Stage 1 - CNS

  • 30min-12hr after ingestion
  • Appears intoxicated (slurred speech, ataxia, stupor, seizure, coma)

Stage 2 - Cardiopulmonary

Stage 3 - Renal

  • 24-72hr after ingestion

Differential Diagnosis

Sedative/hypnotic toxicity

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
  • APAP/ASA levels

Treatment

  1. 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
      • 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
  2. 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
  3. 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)
  4. Decrease oxalate production

See Also

References