Methanol Intoxication - Diagnosis and Management

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Methanol Intoxication;

Diagnosis and Management

Al i Haedar

Clinical Lecturer & Emergency Physician

Department of Emergency Medicine

Faculty of Medicine – Universitas Brawijaya

Saiful Anwar General Hospital

Indonesia



Introduction

• Methanol is odorless and colorless liquid

• Found in:

– deicing solutions,

– windshield washer fluid, – paint removers,

– solvents,

– chafing dish heat sources, and

– other commercial products

• Alcoholics sometimes mix it and other liquids

(i.e., energy drink and soda drink) into ethanol

to get extra effect



Introduction

• Most methanol intoxication cases in Indonesia

are secondary to consumption of mixed liquors

• Alcohol containing liquors in Indonesia, mostlyproduced by home industries

• Very cheap; only USD1 (IDR12,500) per glass

(in some area)

• Emergency doctors may fail to recognize of

patients with ethanol dependence



Prevalence

• 35 cases in year 2010 in ED Saiful AnwarGeneral Hospital Malang

• 17 death cases within 6 hours admission

• >8 million Americans are believed to be

dependent on alcohol, and up to 15% of the

population is considered at risk

• In some studies, more than 50% of all trauma

patients are intoxicated with ethanol at the time

of arrival to the trauma center

ATSDR. Methanol toxicity. Agency for Toxic Substances and Disease Registry. Am Fam Physician. Jan 1993;47(1):163-71

Aufderheide TP, White SM, Brady WJ, et al. Inhalational and percutaneous methanol toxicity in two firefighters. Ann EmergMed. Dec 1993;22(12):1916-8



Toxicity

• Ingestion remains the primary route of exposure.

• Methanol itself is nontoxic; toxicity arises from its

metabolite, formic acid (formate).

• Normal methanol blood level endogen is 0.05

mg/dL

• Asymptomatic individual have peak level <20

mg/dL

• Level >50mg/dL serious poisoning (CNS and eye

problems)

• Fatal case with level >150-200mg/dL

Bronstein AC, Spyker DA, Cantilena LR Jr, Green JL, Rumack BH, Heard SE. 2007 Annual Report of the American

Association of Poison Control Centers' National Poison Data System (NPDS): 25th Annual Report. Clin Toxicol (Phila). Dec

2008;46(10):927-1057. [Medline].

Barceloux DG, Bond GR, Krenzelok EP, et al. American Academy of Clinical Toxicology practice guidelines on the treatment

of methanol poisoning. J Toxicol Clin Toxicol. 2002;40(4):415-46



Methanol

Toxicity

N Engl J Med 2009;360:2216-23.

• Methanol itself is nontoxic; toxicity arisesfrom its metabolite, formic acid (formate)

• HAGMA + Blindness!



Clinical Features

The symptoms of methanol poisoning may not appear for

up to 12 to 18 h after ingestion because of the time it takes

for methanol to be metabolized to it toxic metabolites.

• GI tract : – nausea,

– vomiting, – abdominal pain.

• CNS : – headache,

– confusion,

– decreased level of consciousness.

• Ocular : – retinal oedema and

– hyperaemia of the disk,

– decrease of visual acuity.

• Metabolic acidosis

– Kusmaul type of breathing



Diagnosis

Based on

• history

• the characteristic clinical features

• the presence of wide anion gap

metabolic acidosis and osmolar gap



Management• 1. ABCs / supportive care

– Intubation with RSI method, controlled the ventilation, manage thecirculatory

• 2. Prevent metabolism of methanol – Ethanol IV

– Ethanol via NG tube

* Ethanol’s affinity for enzyme is 10-20 times that of methanol

– Fomepizole* Fomepizole has affinity for alcohol dehydrogenase 8000 times that of

ethanol

• 3. Enhance removal of formic acid – Folate 1mg/kg IV q4h

• 4. Correct acidosis

– Dialysis – Sodium bicarbonate

• 5. Remove methanol – Dialysis

Kosten TR, O'Connor PG: Management of drug and alcohol withdrawal. N Engl J Med 348: 1786, 2003.

Jeffrey Brent, M.D., Ph.D. Fomepizole for Ethylene Glycol and Methanol Poisoning. N Engl J Med 2009;360:2216-23.



Treatment of Methanol Poisoning

AgentIndications

for treatment

Treatment

Methanol

Methanol >20 mg/dL

Ingestion > 0.4 mg/kg

History, symptoms

Suggestive of poisoning

Ethanol IV:

Loading dose: 10% ethanol in D5W at 10

mL/kg over 30 min*

Infuse:10% ethanol in D5W at1.5mL/kg per h

to maintain ethanol level at 100-150mg/dL°, or

Ethanol Oral:

loading dose: 0.8-1 mL/kg PO of 95% ethanol

in 6 oz of orange juice

over 30 min

Average maintenance doses (PO/IV): 0.15

mL/kg/h PO of 95% ETOH

Fomepizole 15mg/kg over 30 min,

Then 10mg/kg q12h X 4 doses

Folinic acid 1mg/kg IV (max 50mg) q4h

NaHCO3 1mEq/kg IV for severe acidosis

Kosten TR, O'Connor PG: Management of drug and alcohol withdrawal. N Engl J Med 348: 1786, 2003.

Jeffrey Brent, M.D., Ph.D. Fomepizole for Ethylene Glycol and Methanol Poisoning. N Engl J Med 2009;360:2216-23.



Effects of Alcohol

• Ethanol’s affinity for enzyme is 10-20 times that of methanol

• Alcohol competes with Methanol



N Engl J Med 2009;360:2216-23.

Effects of

Fomepizole



Dialysis

Indication for dialysiswith methanolintoxication:

1. Sign of visual or

CNS dysfunction2. Peak methanol

level >20 mg/dL

3. pH< 7.15

4. History of

ingestion >30 mLmethanol

Toxicology & pharmacology, Emergency Medicine, a Comprehensive study guide, JE Tintinalli, 2004, 6 th ed,section 14,page 1067

Ekins BR, Rollins DE, Duffy DP, et al: Standardized treatment of severe methanol poisoning with ethanol and hemodialysis. West J Med1985 Mar; 142:337-340



Facts

• We do NOT have ethanol 20% or 40%

solution in Indonesia

• We administered liquor like Chivas Regal

(the alcohol concentration ~ 40%)

• Alcohol 70% + water + contamination of

bacteria & yeast = METHANOL !!!



How do we administer ethanol?

IV:

• More benefitial

• More rapid action

• No ethanol IV preparation in Indonesia• Do not use oral ethanol preparations IV!!!

NGT:

• 40% ethanol containing liquor mix with D5%(equal volume)

Toxicology & pharmacology, Emergency Medicine, a Comprehensive study guide, JE Tintinalli,2004, 6th ed,section 14,page 1067



Charcoal?

• Because toxic methanols are absorbed so

rapidly, gastric emptying is unlikely to be of

benefit, and there is no evidence to support its

routine use.

• Activated charcoal is not indicated for methanol

ingestions, although if co-ingestion of an agent

known to adsorb to charcoal is suspected, it

may be given for this reason.

Toxicology & pharmacology, Emergency Medicine, a Comprehensive study guide, JE Tintinalli,2004, 6th ed,section 14,page 1067



Challenges

• ? medico-legal ethic

• ? components other than alcohol

inside the liquor



Differential Diagnosis

• High Anion Gap Metabolic Acidosis

M methanol

U uremia

D DKA, ketonesP paraldehyde

I INH, Iron

L lactate

E Ethanol, Ethylene glycol

S salicylates



Prognosis

• Mortality >80% if present with

either:

– Severe metabolic acidosis (pH <7)

– Seizures

– Coma

• Mortality <6% in absence of above



Discussion

• We diagnose patient with methanol

intoxication based on the history and

clinical presentation.

• The most initial symptom of methanol

intoxication is visual impairment, seen in

50% of patients

• This symptom will manifest around 2 days

after consumption



Discussion

• Many hospitals are not supported

with the test of ethanol, methanol,

or other alcohol level.

• We diagnose patient with methanol

intoxication based on the history

and clinical presentation, with high

anion gap acid base analyze.



Discussion

• Prognosis is correlated with the degree

of metabolic acidosis (and the quantity

of methanol ingested); more severe

acidosis confers a poorer prognosis.

• Direct correlation exists between the

formic acid concentration and the

pathologies



Summary

How to improve the outcomes?

• Early recognition

• Aggressive treatment by supportingairway & breathing

• Inhibiting metabolism of methanol



Thank You

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Methanol Intoxication - Diagnosis and Management

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