136. Toxic Etoh Flashcards by Tegan Turner

What is methanol?

Clear, voltatile, colorless slightly sweet alc st room temp.
Aka wood alcohol

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What things commonly have methanol?

Solvent or octane booster in gasoline
Windshield washer fluid
Antifreeze (brake line sp)
Embalming fluid
Camp stove fuel

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How is methanol absorbed?

Gi
Average half life 5 mins, peak 30-60 mins

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What is the toxic metabolite of methanol?

Formic acid then into formate and H ions

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How is methanol metabolized?

Liver- ADH to formaldehyde
ThEN by ALDH to formic acid
Then THF to 10-formyl THF
to co2 and water

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Ethanol metabolism to acetyl coa

By adh to acetylaldehyde
ALDH to
Acetate
Acetyl coa synthase to acetyl coa

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Ethylene glycol 3 end products

Glycine
Oxalic acid
Alpha hydroxy beta keyoadipate

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Ethylene glycol metabolism to 3 products

by adh to glycoaldehyde
ALDH to
Glycolic acid
A. Go and LDH to oxalic acid
B by pyridoxine to glycine
C by thiamine to alpha hydroxy beta ketoadipate

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At toxic concentrations how long is half life of methanol?

24 h

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With ADH inhibition by ethanol or fomepizole, half life of methanol extends to ?

Vs dialysis half life is ?

Upward of 50
Approx 3-4 hours

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How does formic acid muck things up?

Binds iron to cause mitochondrial cyctochtome oxidase inhibition so interferes with oxidative metabolism (similar cn, co, hso4)

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What concerning symptoms and diagnoses can methanol cause in the eye?

Optic disk of retina and retrolaminar optic nerve - inhibition of mitochondrial cytochrome oxidase —> myelin sheath damage and loss of vision

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Basal ganglia and sub cortical white matter effected how by methanol?

inhibition of mitochondrial cytochrome oxidase —> myelin sheath damage

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Major systems effected in methanol toxicity ?

Gi
Cns
Optic

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Most characteristic vision change of methanol?

Spots with blurred vision/snowstorm vision
Altered visual fields
Blindness

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Physical exam signs methanol toxicity

Reduced pupillary response to light
Hyperaemia optic disk
Edema retina
Loss of optic disk cupping
Central scotimata

Tachypnea
Shock
Rhabdo
Myoglobinuria
Death -cerebral edema and multi organ failure

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Name 10 causes of an increased osmolar gap

Methanol
Ethylene glycol
Ethanol
Mannitol
Acetone
Fructose
Hyperlupidemia
Dka
Alcohol ketosis
Sickle cell
Multi organ failure
Septic shock
Uremia

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Name 12 causes of anion gap elevation

Alcohol ketosis
Cyanide, co, colchicine
Acetaminophen
Toluene
Paraldehyde
Propylene glycol
Phenformin
Isoniazid, iron, ibuprofen
LA (sepsis, ischemia)
Ethylene glycol
Salicyclates
Methanol, metformin
Uremia
Dka

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Name 7 causes of a double anion gap

Methanol
Ethylene glycol
Dka
Alc ketoacidossi
Uremia
Septic shock
Multi organ failure

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Toxic etoh: vision loss?

Methanol

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Toxic etoh hypocalcemia and calcium oxalare crystals

Ethylene glycol

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Prognostic factors regarding methanol ingestion

Degree of acidosis (most important - high mortality at ph less than 7)
Time to presentation
Imitation of treatment

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Why can methanol present with Parkinson’s like sx?

Effects on putamen and sub cortical white matter

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Corrected AG equation for albumin

AG + (2.5 x (measured serum albumin)) when albumin is g/dL

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Decreased albumin can falsely ? AG?

Elevate

How to calculate osmolarity

2Na + glucose + bun

Normal osmolarity gap?

Measured - calc = 10 (higher = concerning)

Management of methanol toxicity

1. ABC 2. Na bicarb if ph <7.3: 1-2 new/kg and infuse 150 new/L in 5% dextrose at 1.5-2x maintenance until ph I’d 7.35-7.45 3. Fomepezole: load 15mg/kg iv then 10mg/kg q 12,) yo to 48 h thebc15mg/kg q12g If Hd - same dose as above, start maintenance 6h after loading dose then every 4 hours

When to initiate fomepazole?

Plasma methanol or EG [] >/= 20 Hx of ingestion or EG and osmolar gap > 10 Or Strong suspicion of methanol or EG and at least two: - ph <7.3 - serum bicarb <20 - osmolar gap > 10 -urine oxalate crystal present (for EG)

Indications of HD for methanol

Ph <7.3 Renal failure Vision abnormality with me thinks exposure Hyperkalemia R to tx HD instability MEthanol or EG > 50

Dispo for methanol toxic pt

Nephro Optho IM Tox

Ethylene glycol - what is this?

colourless odoeee sweet tasting liquid

Ethylene glycol often found in what products?

Antifreeze Hydraulic brake fluids Industrial solvents Foam stabilizer Paint Cosmetic

Ethylene glycol absorption?

GI, 1-4 hours

Ethylene glycol metabolism

Liver

Ethylene glycol - where do crystals precipitate in the kidney?

Proximal tubule

Ethylene glycol - other deposits than kidney?

Brain Intestine Heart Lungs Spleeb

Ethylene glycol why get hypocalcemia?

Chelation of calcium by oxalate

Ethylene glycol - necrosis and lysis?

Myonecrosis Rhabdo

Ethylene glycol- name 3 stages of toxicity?

1. Acute neuro 2. Cardiopulmonary 3. Renal

Ethylene glycol- acute neuro stage finding and timing

30min-12 hours Inebriation, euphoria, coma, seizures, nystagmus, ataxia, myoclonic jerks

Ethylene glycol- cardiopulmonary stage?

12-24 h post infection Tachycardia Severe metabolic acidosis from glycolic acid ARDS

Ethylene glycol- renal stage?

24-48 hours post - ARf From calcium oxalate crystals Flank pain CVA tender Hematuria Proteinuria Various amounts of pee

Ethylene glycol- what is frequently required in the HD stage?

Dialysis

List 4 examples of delayed neuro sequelae of Ethylene glycol

Bulbar palsy cn VII opthalmoplegia Auditory dysfunction Dysphagia?

Ddx eythelne glycol - causing ARF?

abx - aminoglycosides, vanco, sulfa drugs, cipro, pneicillin NSAID acei arb hmg coa reductase inhib antivirals amphotericin B chem o -mtx, cisplastin bisphosphonates heavy metals PPI

DDX of hypocalcemia other than EG?

proton pump inhibitors, bisphosphonates, other phosphate-containing substances (e.g., laxatives and sodium phosphate), loop diuretics, glucocorticoids, calcitonin, cisplatin, pentamidine, interferon-alfa, fluorides (e.g., hydrofluoric acid), citrate, phenytoin, phenobarbital, carbamazepine, estrogens, and ethylenediaminetetraacetic acid

when are crystals found in urine of EG tox?

4-8 hours post exposure

What predicts mortality and cr rise in EG?

acidosis pH <7.2-7.3

what measurement/lab value to ask for in EG toxciity suspected?

ycolic acid concentrations greater than 99 mg/dL are strongly associated with severe CNS toxicity and mortal- ity. Levels greater than 76 mg/dL have nearly 100% sensitivity for pre- dicting ARF.28 Glycolic acid levels greater than 60 mg/dL could be an indication for HD, but this is not well validated

EG similar tx to methanol - what two cofactorsshould also be given to pt malnourished, with etoh hx?

thiamine 100 mg IV daily, and pyridoxine 100 mg IV daily, for 2 days.

Isopropyl alcohol - what is this?

colorless, lcear liquid, fruity odor bitter taste

Isopropyl alcohol - found in?

rubbing alcohol, antifreeze, disinfectants, cleaning solutions, skin and hair products, and hand sanitizers.

Isopropyl alcohol: GI absorption timeline?

within 30 mins

Isopropyl alcohol: acetone peak plasma concentration?

peak plasma 7-30hours post exposure half life up to 24h

Isopropyl alcohol: sx

GI - Nausea, vomiting, and abdominal pain typ- ically ensue, but hemorrhagic gastritis, hematemesis, and significant blood loss can result with larger ingestions. CNS - miosis amongst dizzy, ataxic, hypotnic LOC - aspiration pneumonitis hypothermia with large invgestion NOT hypoglycemia

Isopropyl alcohol definitive method of dx?

IPA

Isopropyl alcohol: management.

supportive wash skin with soap and water PPI for hemorrhagic gastritis GI if bleeding hypotension - IVF

Isopropyl alcohol: Persistent hypotension despite 4L and NE?

Isopropyl alcohol: fomepazole?

NO prolong hypotensive and CNS depressent effects prolonged

What is DEG?

odorloss viscous sweet tasking liquid in brake fluid, antifreeze, lubricants, wallpa- per strippers, and artificial fog machine solution most in pharm preps of expensive glycols management like EG and methanol, no crystals

PG - what is this? found in?

PG is commonly used as a solvent in various pharmaceutical prod- ucts and in antifreeze and hydraulic fluids. Common medications that use PG as a diluent include IV phenytoin, lorazepam, diazepam, eto- midate, nitroglycerin, phenobarbital, hydralazine, and trimethoprim- sulfamethoxazole

PG - tx options

Treatment typically involves stopping the offending agent, but HD and ADH blockade can be considered for severe acidosis and metabolic abnormalities

A 24-year-old man presents after intentional methanol ingestion. The patient reports that 1 or 2 hours ago he drank approximately 8 ounces of windshield washer fluid in a suicide attempt. He is not sure of the product name. His only current complaint is slight nausea. His vital signs and physical examination are within nor- mal limits. Serum chemistry reveals the following: sodium, 142 mEq/L, potassium, 4.5 mEq/L, chloride, 110 mEq/L, bicarbonate, 22 mEq/L, blood urea nitrogen (BUN), 18 mg/dL, creatinine, 1.5 mg/dL, and glucose, 111 mg/dL. Serum methanol levels are not obtainable at your hospital. The psychiatry service asks if the patient is medically cleared. Which of the following is the most appropriate response?

a. The patient is cleared; he has a normal anion gap, so no signifi- cant methanol ingestion occurred. b. The patient is cleared; ingestion of 8 ounces is below the toxic level regardless of the concentration. c. The patient is not cleared; he has an elevated anion gap and needs to receive treatment for methanol toxicity. d. The patient is not cleared; he has evidence of renal failure and needs to receive treatment for methanol toxicity. e. The patient is not cleared; not enough time has elapsed from the ingestion to determine if significant toxicity has occurred. e

A 44-year-old woman complains of abdominal pain and headache. Her family reports that the patient drank “something” approxi- mately 8 hours ago in a suicide attempt. The patient is sleepy but arouses with manual stimulation. Her speech is confused, but she follows all simple commands. Her vital signs are blood pressure, 124/82 mm Hg, heart rate, 108 beats/min, respiratory rate, 26 breaths/min, and temperature, 37.0°C (98.6°F). Her physical exam- ination is unremarkable. Her serum chemistry reveals an anion gap of 24 mEq/L. Other laboratory work is pending. Which of the fol- lowing treatments should be administered initially? a. Diuresis b. Hemoperfusion c. Intravenousflumazenil d. Intravenous fomepizole e. Oral activated charcoal

An otherwise healthy patient presents after suicidal ethylene gly- col ingestion. He is drowsy. His serum pH is 7.1. You have started treatment with fomepizole and have contacted the nephrologist to arrange hemodialysis. In the meantime, what should be done about the patient’s acidosis? a. Normal saline should be administered to facilitate clearance of the acid. b. Nothing should be done; dialysis will correct the acidosis. c. Nothingshouldbedone;thefomepizolewillcorrecttheacidosis. d. Nothingshouldbedone;thepatientisnottrulyacidotic,buteth- ylene glycol interferes with the laboratory determination of pH. e. Sodium bicarbonate should be administered to neutralize the exogenous acid.

5. Which of the following is an indication for hemodialysis after meth- anol or ethylene glycol ingestion? a. Metabolicacidosis b. Blood level of 10 mg/dL c. Elevated anion gap d. Hypocalcemia

Whichofthefollowingcofactorshelpswiththeeliminationofmeth- anol and should be considered in patients with methanol poisoning? a. Folinic acid (leucovorin) b. Hydroxocobalamin (vitamin B12) c. Niacin (vitamin B3) d. Pyridoxine (vitamin B6) e. Thiamine (vitamin B1)

Which of the following statements comparing the effects of isopro- pyl alcohol and ethylene glycol is true? a. Isopropyl alcohol causes less CNS depression and is less toxic than ethylene glycol. b. Isopropyl alcohol causes less CNS depression and is more toxic than ethylene glycol. c. Isopropyl alcohol causes more CNS depression and is less toxic than ethylene glycol. d. Isopropyl alcohol causes more CNS depression and is more toxic than ethylene glycol. e. Isopropyl alcohol has the same effects as ethylene glycol.

A patient presents with decreased mental status after drinking some homemade alcohol. Serum chemistry reveals sodium, 140 mEq/L, potassium, 4.5 mEq/L, chloride, 108 mEq/L, bicarbonate, 22 mEq/L, BUN, 28 mg/dL, creatinine, 1.0 mg/dL, glucose, 90 mg/dL, and serum osmolality, 320 mOsm/kg. Urinalysis is posi- tive for ketones. Which of the following is the most likely alcohol ingested? a. Ethanol b. Ethylene glycol c. Isopropylalcohol d. Methanol e. On the basis of this information, the patient probably did not ingest an alcohol.

136. Toxic Etoh Flashcards

(70 cards)