Intro to Medical Toxicology:
A General Approach to the Poisoned Patient
Objectives
-List two indications for endotracheal
intubation in the setting of drug overdose
-Discuss a general approach to the use of
gastrointestinal decontamination in the care
of the poisoned patient
-Describe some pitfalls to a urine drug screen
-Recite the phone number to reach a poison
center in the US
Medical Toxicology
-Clinical subspecialty that includes
monitoring, prevention, evaluation,
and treatment of injury and illness
due to occupational and environmental
exposures, pharmaceutical agents, as
well as unintentional and intentional
poisoning in all age groups
Types of Exposures
-Occupational Exposure
-Drug Overdose-Unintentional and Intentional
-Pharmaceuticals & Illicit drugs
Environmental Exposure
-Plants
-Heavy metals
-Toxic Gases
-Envenomations
Routes of Exposures
Ocular, Dermal, Inhalation, Ingestion, Parenteral
Hades Bone Beet Polyester Suit Flask
-blind = cant constrict pupils
-mad = heavy metals
-hot = hyperthermia
-mucous mem dry
-red = flush
-flask = full as a flask – urinary retention
GI Decontamination Methods
-use wisely! Evaluate each case individually! Look at risks &
potential benefits.
Syrup of ipecac
Gastric lavage
Single-dose activated charcoal : dec absorption of drug, don’t
give if risk of aspiration.
Cathartics (electrolyte problems)
Whole bowel irrigation
GI Decontamination
“Overall, the mortality from acute poisoning is
less than 1% and the challenge for clinicians
managing poisoned patients is to identify
promptly those who are most at risk of developing
serious complications and who might potentially
benefit, therefore, from gastrointestinal
decontamination”
Clin Tox 1997
Management Overview
Airway
Breathing
Circulation
Disability
Exposure (undress)
Antidote (may prevent intubation)
Basics
Consider charcoal
Decontamination
Enhance elimination
Exposure Examples
Uncommon
CO, toxic alcohols
Iatrogenic
Common high acuity
Neuro toxic agents
Cardiotoxic agents
Common
Acetaminophen
Airway
Lack of adequate airway is the most common cause
of morbidity and mortality in the setting of OD
Indications for endotracheal intubation
Hypoxemia (mod to severe)
Hypercapnia (mod to severe)
Inadequate airway protection
Toxidrome
A set of clinical signs and symptoms that suggest a
class of poisoning
-know if it reeves you up or down by drug &
withdrawal (dif clinical approaches)
-alcohol & benzo withdrawl = life threatening
-opiod withdrawl = not life threatening, reeved up
-meth & cocaine = reeves ups but no urinary retention
& still have bowel sounds. Sympathomementic =
sweating, not dry
Drug Screen
General Principles
Availability
Timing of tests
Will results change management? Rare to change
management in acute OD
Anticholinergic Toxidrome
Blind Mad Hot Dry Red Tachy Full Bat Hatter
Opioid toxidrome: downer (see case #2)
Urine Drug Screen
It is an ok test but not great! You are more likely to get a
false negative. The more synthetic the drug the less likely
you will pick it up on a drug screen – need to run specific
tests. Need to send for confirmatory test – immunoassay!
-Indications
-Confirm or exclude exposures, maybe
-Quantitative testing may have prognostic significance
-Occupational testing
-Medico-legal implications: DWI, pediatric exposures
-Guide management of confirmed poisonings
-ICU vs Floor vs discharge planning
-Prepare for specific antidote/treatment
-Monitor effectiveness of treatment
-Identify patterns of exposure or use
Urine Drug Screen
Methods
Immunoassays
Qualitative
Screen
Urine Drug Screen: Drug Classes
Amphetamines
Barbiturates
Benzodiazepines
Cocaine
metabolites
Marijuana
metabolites
Opiates
Phencyclidine
Tricyclic
antidepressants
Urine Drug Screen: Benefits
Few classes of drugs responsible for
majority of exposures
Unexplained signs/symptoms
May demonstrate exposure
Identify patterns of exposure
Long term pain management
Urine Drug Screen: Pitfalls
Failure to recognize limitations of test
False negative frequent
Immunoassay is not confirmatory
Result may not reflect current use
Treating test, not patient
Acetaminophen may be missed if only using clinical exam
e.g. Opioid combinations, OTCs
Omitting other tests which may help
ECG, radiographs
Poison control!!!! MD on call 24/7
1-800-222-1222
Practice Questions
Define toxidrome
What drugs reeve you up or down? What about
withdrawal of these drugs?
3. List characteristics of Anticholinergic Toxidrome
4. T/F Use GI decontamination wisely & evaluate on an
individual basis
5. What is the most common cause of morbidity and
mortality in the setting of OD
6. T/F urine testing is a specific, sensitive test with
limited false positives and negatives
7. List a few pros & cons of urine testing
1.
2.
Answers:
1. A set of clinical signs and symptoms that suggest a
2.
3.
4.
5.
6.
7.
class of poisoning
Up = Anticholinergic; down = opioids; withdrawl =
opposite of effect
Blind Mad Hot Dry Red Tachy Full Bat Hatter
Hades Bone Beet Polyester Suit Flask
T
Lack of airway
F
Urine Drug Screen: Benefits
Few classes of drugs
responsible for
majority of exposures
Unexplained signs/symptoms
May demonstrate exposure
Identify patterns of exposure
Long term pain management
Urine Drug Screen: Pitfalls
Failure to recognize
limitations of test
False negative frequent
Immunoassay is not
confirmatory
Result may not reflect
current use
Treating test, not patient
Acetaminophen may be
missed if only using clinical
exam
e.g. Opioid combinations,
OTCs
Omitting other tests which
may help
ECG, radiographs