Approach to Toxicology

8/13/2019 Approach to Toxicology

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General Approach tothe Poisoned Patient

LTC Mike Miller, MD, FACEP

CPT Lisa M. Yungmann M.D.

Darnall Army Community Hospital

Government Services Chapter

American College of Emergency Physicians


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Why do we discuss toxicology?

In practice, toxicology makes up 5-

30% of your cases

Inservice and written boards, about 8%

Oral boards, about 15%


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But reallytoxicology is fun

Know common tox

presentations and

antidotes, and you

can save a life

The physiology and

science of toxicsubstances is cool

Theres always

some new drug to


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Poison facts

>2 million toxic exposures per year

More than half of exposures,


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Objectives

Supportive care is main means to

decrease morbidity and mortality

Learn about gastric decontamination

Learn and know all antidotes

Know toxidromes and treatment


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General Approach

ABCs of Toxicology

A-Antidotes and alter absorption (insome instances prior to airway-decontamination with

organophosphates to protect others, cyanide toxicity whereantidotes are lifesaving)

B-Basics; ABCs

C-Change metabolism (NAC, ethanol)

D-Distribute differently (calcium gluconate,O2)

E-Elimination (diuresis, dialysis, hemoperfusion)


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GI contamination

Charcoal-now procedure of choice if

appropriate substance. Major risk is

aspiration.

May use NG/OG tube or give orally.

If giving orally, assure patient is awakeand airway protected.


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Multidose Charcoal

Used with some select drugs

Used to interrupt enterohepaticrecirculation.

Do not use sorbitol with MDAC

Useful for: carbamazapine, theophylline,barbituates, salicylates, dapsone, depakote,

digoxin, quinine


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GI contamination-when charcoal

doesnt work

C-Caustics

H-Hydrocarbons

A-Alcohols

I-Iron

L-Lithium L-Lead(and other heavy

metals)


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Consider whole bowel irrigation

for:

Drugs where

charcoal can not be

used

Sustained release

preparations

Body packers

Large quantities of

toxic substances


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To lavage or not?

Controversial

Indicated for recent ingestions


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Are any lab values helpful?

ECG

Chem 7 Acetaminophen level

Serum osmolality

VBG (determine pH)


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Useful lab values

Calculate the anion gap

AG=Na-(HCO3+Cl) Causes anion gap:

AT MUDPILES (alcohols, toluene, methanol,

paraldehyde/phen phen, iron/INH, lactic acidosis,ethylene glycol, salicylates/strychnine)


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Useful lab values

Osmolar gap=measure serum

osmolality-calculated serum osmolality

Calculated=2Na+glucose/18+BUN/2+

ethanol/6

Causes Osmolar Gap:

ME DIE (methanol, ethanol, diuretic, isopropyl,ethylene glycol)


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Drugs to Dialyze-STUMBLE

S-Salicylates

T-Theophylline U-Urea

M-Methanol

B-Barbituates

L-Lithium

E-Ethylene glycol


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Case #1

A 19 y/o raver dropped off in your EDby his raving buddies after punching

the bouncer and trying to jump out ofhis friends car into the middle of theGW Parkway.

He is cursing and screaming BP 200/110, P 120, T 100.7, R 22,

O2 97% RA


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Case #1

The raver continues to curse and yell

He is diaphoretic, pupils dilated,piloerection is noted

What toxidrome is presented here?


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Sympathomimetic

Hypertension,

tachycardia,

diaphoresis,psychotic behavior

Tmt:

1.Benzos2.Benzos

3.Nitroprusside, phentolamine or

dexmedetomidine

4.Do NOT acidify urine


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Case#2

And yet another 19 y/o raver broughtin by his friends for similar behavior as

the guy on your last shift. BP180/90, P95, T98.7, R20,

O298%RA

He is as pissed off as the other guy,pupils dilated, his face is red, but he isnot sweating like your previous guy

Toxidrome?


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Anticholinergic

Presents similar tosympathomimetic

without thediaphoresis

Turns out thisparticular patient got

Benadryl instead ofMDMA. When thefirst one did not work,he ate 20 more

TMT:supportive, cool,benzodiazepines, consider


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Case #3

25 y/o landscaper brought by his

coworker into the ER obtunded

BP 90/40 P40 R8 T98.7 O275%NRB

He is obtunded, has copious wet

secretions and diarrhea, pupils pinpoint What toxidrome is presented here?


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Cholinergic

DUMBELS-diarrhea, urination,

miosis,bradycardia,emesis, lacrimation,salivation

TMT:*decontaminate pt. iforganophophate

*Atropine

*2-PAM until secretions


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CASE #4

You are working the Saturday night

shift when a 18 y/o female is dropped

out of a speeding BMW

She is taking shallow breaths and is

unconscious BP90/40, P50, R5, T97.8, O2

68%NRB


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CASE #4

Her pupils arepinpoint and herrespiratory effort ifminimal

You notice marks onher arms

Toxidrome? Opioids

TMT:

*Naloxone

*supportive


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An important note

Opioids and sedative

hypnotics can appear

the same Pupils will usually be

spared with sedative-

hypnotics (s-h)

Respirations mostly

preserved with s-h

Examples:GHB,

benzos, ethanol,


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Case #5

This patient is a 35 y/o female with a

history of depression and multiple

psychiatric admissions for OD

Her husband brings her to the ED

saying he thinks she overdosed again BP175/100, P125, T100.7, R22,

O298%


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Case #5

She is agitated and can not stop

moving around

In site of IV fluids, she remains

tachycardic and somewhat psychotic

What drug has she overdosedon/toxidrome?


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SSRI/Serotonin syndrome

Altered MS, agitation, fever, tremors, ataxia

Be careful as serotonin syndrome can mimicthyrotoxicosis (a deadly disease if missed), NMS,MAOIs/tryptophan, and withdrawal symptoms

Usually diagnosed per med history

Can present weeks after stopping SSRI

TMT:

*benzos

*supportive

*cyproheptadine


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Antidotes

Acetaminophen-NAC

Arsenic-BAL

Mercury-BAL

Lead-Dimercaprol, EDTA

Carbon monoxide-O2,

hyperbaric in severe/pregnant

Cyanide-amyl nitrite OR

sodium nitrite, sodium

thiosulfate

Ethylene glycol/methanol-

ethanol, fomepizole

Iron-deferoximine

Nitrites-methylene blue

Organophosphates-atropine,

pralidoxime (2-PAM)

Opioids-naloxone

Phenothiazines-diphenhydramine,

Benzotropine

Isoniazid (INH)-pyridoxine

Digoxin/Oleander-Digitalis Fabfragments


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In Summary

ABCs including early antidotes

GI decontamination early

Get a good overdose history if possible

Look at the patient and try to match

clinical symptoms with a toxidrome Look for skin markings/do you smell

anything unusual?

Get poison center involved


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Questions?

Documents

Approach to Toxicology