1.   Toxic Alcohols
Pathophysiology of methanol and ethylene glycol overdose
Clinical presentation of methanol and ethylene glycol overdose
Management of methanol and ethylene glycol overdose
Antidote and hemodialysis in toxic alcohol
Zohair Al Aseri MD,FRCPC EM & CCM

2. METHANOL Perspective Certain products found in the home Antifreeze;
Windshield washer fluid;
Carburetor fluid;
Glass cleaners
Thinners
Adhesives
Zohair Al Aseri MD,FRCPC EM & CCM

3. METHANOL
Perspective
Treatment delay is associated with increased morbidity, making early recognition of clinical and laboratory clues crucial.
Zohair Al Aseri MD,FRCPC EM & CCM

4. Pharmacology and Metabolism
Principles of Disease
Pharmacology and Metabolism
Methanol is absorbed rapidly from the gastrointestinal tract, and blood levels peak 30 to 60 minutes after ingestion.
Inhalational abuse of methanol is a recent trend that can result in toxic serum levels.
Zohair Al Aseri MD,FRCPC EM & CCM

5. Pharmacology and Metabolism
Principles of Disease
Pharmacology and Metabolism
A prolonged half-life of 24 to 30 hours results,
Small amounts of ingested methanol may be exceptionally toxic.
The smallest lethal dose reported is 15 mL of 40% methanol
Zohair Al Aseri MD,FRCPC EM & CCM

6. Pharmacology and Metabolism
Principles of Disease
Pharmacology and Metabolism
Methanol is oxidized by alcohol dehydrogenase (ADH) to formaldehyde, which is rapidly converted by aldehyde dehydrogenase to formic acid.
Zohair Al Aseri MD,FRCPC EM & CCM

7. Pharmacology and Metabolism
Principles of Disease
Pharmacology and Metabolism
Formic acid is the primary toxicant and accounts for much of the anion gap metabolic acidosis and ocular toxicity peculiar to methanol ingestion.
Zohair Al Aseri MD,FRCPC EM & CCM

8. Metabolism of methanol
Zohair Al Aseri MD,FRCPC EM & CCM

9. Pathophysiology
Diagnosis should be considered in patients with altered mental status, visual complaints, or metabolic acidosis
Symptoms are primarily neurologic, gastrointestinal, or ocular in nature.
Zohair Al Aseri MD,FRCPC EM & CCM

10. Clinical Features Prognosis correlate with the degree of acidosis
time to presentation
initiation of treatment within 8 hours of exposure.
coma, seizures
pH less than 7.0.
Zohair Al Aseri MD,FRCPC EM & CCM

11. Diagnostic Strategies
A severe anion gap metabolic acidosis
Because the onset of acidosis may be delayed 12 to 24 hours, the presence of a normal anion gap does not rule out methanol exposure.
anion gap is due primarily to the presence of formic acid, with a variable contribution from lactic acid
Zohair Al Aseri MD,FRCPC EM & CCM

12. serum toxic alcohol level is necessary
Diagnostic Strategies
High osmol gap.
serum toxic alcohol level is necessary
Zohair Al Aseri MD,FRCPC EM & CCM

13. Differential Considerations
Ethylene glycol and methanol may cause a “double gap” (i.e., an osmol gap in addition to the anion gap).
Zohair Al Aseri MD,FRCPC EM & CCM

14. Most ethylene glycol poisonings occur with antifreeze.
Perspective
Ethylene glycol is a viscous, colorless, odorless, slightly sweet-tasting liquid.
Most ethylene glycol poisonings occur with antifreeze.
Zohair Al Aseri MD,FRCPC EM & CCM

15. Pathophysiology
2.3%of a dose of ethylene glycol ultimately is converted to oxalic acid
Anion gap metabolic acidosis caused mainly by glycolic acid
Zohair Al Aseri MD,FRCPC EM & CCM

16. Clinical Features
The clinical syndrome with ethylene glycol ingestionis divided into four stages:
acute neurologic stage
cardiopulmonary stage
renal stage
delayed neurologic sequelae stage
Patients may die in any stage
Zohair Al Aseri MD,FRCPC EM & CCM

17. Diagnostic Strategies
serum electrolytes, calcium, BUN, creatinine,
serum glucose,
serum osmolality, blood ethanol level,
ABG,
ethylene glycol level
Electrocardiogram
urinalysis.
crystalluria is considered the hallmark of ethylene glycol ingestion, its absence does not rule out the diagnosis because less than half of patients have this finding.
Zohair Al Aseri MD,FRCPC EM & CCM

18. Diagnostic Strategies
Freshly voided urine can be examined for fluorescence with a Wood's lamp.
Sodium fluoresceinis added to antifreeze to aid in the detection of radiator leaks.
Urinary fluorescence may be seen 6 hours after ingestion of fluorescein-containing antifreeze.
The lack of fluorescence does not rule out ethylene glycol ingestion
Zohair Al Aseri MD,FRCPC EM & CCM

19. Management
Methanol and ethylene glycol ingestions are treated essentially the same
Resuscitation and stabilization are paramount.
For any significant history of exposure, treatment should be initiated pending a confirmatory toxic alcohol blood level.
Zohair Al Aseri MD,FRCPC EM & CCM

20. Management Intubate early
Gastric emptying has not been shown to alter clinical course or outcome and may be associated with complications
Activated charcoal is not useful.
Intubate early
Zohair Al Aseri MD,FRCPC EM & CCM

21. Management 3 ttt goals for methanol or ethylene glycol toxicity:
(1) correction of metabolic acidosis with bicarbonate
(2) ADH enzyme blockade, which inhibits the metabolism of methanol and ethylene glycol to toxic metabolites
(3) removal of the parent alcohol and its metabolites by hemodialysis.
Zohair Al Aseri MD,FRCPC EM & CCM

22. Management
Depending on the severity of the patient's acidosis, IV bicarbonate can be administered
With ethylene glycol, the potential for worsened hypocalcemia sodium with bicarbonate should be considered.
Zohair Al Aseri MD,FRCPC EM & CCM

23. Management
Metabolism of the parent compounds by the enzyme ADH must be blocked by either ethanol or fomepizole (Antizol).
Zohair Al Aseri MD,FRCPC EM & CCM

24. Management Ethanol may be given orally or intravenously.
Potential side effects of IV administration include
CNS depression
Respiratory depression
Hypotension
Vomiting
Hypoglycemia
Thrombophlebitis
Oral ethanol loading may be associated with gastritis.
Zohair Al Aseri MD,FRCPC EM & CCM

25. Dosing changes are required during hemodialysis.
Management
Fomepizole
Blocks the metabolism of methanol and ethylene glycol
Fomepizoleis a pregnancy category C drug
Dosing changes are required during hemodialysis.
Zohair Al Aseri MD,FRCPC EM & CCM

26. Management Hemodialysis Indications metabolic acidosis
renal compromise
visual symptoms (methanol)
deterioration despite intensive supportive care
electrolyte imbalances
unresponsive to conventional therapy.
Zohair Al Aseri MD,FRCPC EM & CCM

27. Management
Ethanol or Fomepizole
Hemodialysis
50 mg of leucovorin (folinic acid) should be given for methanol toxicity
In ethylene glycol cofactors thiamine and pyridoxine empirical administration is reasonable
IV calcium for symptomatic hypocalcemia
Magnesium is a cofactor along with thiamine for the detoxification of glycolic acid and should be replaced in patients who are deficient.
If hemodiyalsis is not available, the patient should be givenan ADH inhibitor and transferred to a setting where dialysis is available.
Zohair Al Aseri MD,FRCPC EM & CCM