This document provides an overview of toxicology basics for medical students. It discusses approaches to toxicology patients including decontamination techniques, common toxidromes like narcotic, sympathomimetic, anticholinergic, and cholinergic. It also reviews substances that cause each toxidrome and their treatments, emphasizing supportive care and specific antidotes when available. The goal is to recognize toxidromes, identify substances, and initiate appropriate emergency management of overdose patients.
History Class XII Ch. 3 Kinship, Caste and Class (1).pptx
GEMC: Basics of Toxicology: Resident Training
1. Project: Ghana Emergency Medicine Collaborative
Document Title: Basics of Toxicology
Author(s): Patrick Carter, MD, University of Michigan Medical School
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2
3. Basics of ToxicologyBasics of Toxicology
Medical Student LectureMedical Student Lecture
SeriesSeries
Emergency MedicineEmergency Medicine
revised 6/2009
3
4. ObjectivesObjectives
Describe the role of GI decontaminationDescribe the role of GI decontamination
Recognize common toxidromesRecognize common toxidromes
Recognize substances for whichRecognize substances for which
specific antidotes existspecific antidotes exist
Initiate ED management of a patientInitiate ED management of a patient
with an overdosewith an overdose
4
5. The undifferentiated patientThe undifferentiated patient
A patient is dropped off at the ED door.A patient is dropped off at the ED door.
He is minimally responsive. His friendsHe is minimally responsive. His friends
say they think he took something andsay they think he took something and
drive off…drive off…
Where do we start?Where do we start?
5
6. Approach toApproach to (possible)(possible) Tox patientTox patient
Simultaneous treatment & diagnosisSimultaneous treatment & diagnosis
Immediate action:Immediate action:
ABC(D) , IV / O2 / monitorABC(D) , IV / O2 / monitor
Thinking:Thinking:
Is this a tox problem?Is this a tox problem?
If yes, are there complicating factors?If yes, are there complicating factors?
Got drunk and fell down, now with head injury?Got drunk and fell down, now with head injury?
Resources to get a history?Resources to get a history?
6
7. Approach toApproach to (likely)(likely) Tox patientTox patient
YouYou’ve considered a differential and you think’ve considered a differential and you think
it is a toxicologic issueit is a toxicologic issue
Immediate action:Immediate action:
Supportive therapy (airway etc)Supportive therapy (airway etc)
DecontaminationDecontamination
Thinking:Thinking:
Toxidrome present?Toxidrome present?
What more information do I need?What more information do I need?
Definitive ManagementDefinitive Management
Is there an antidote or specific treatment?Is there an antidote or specific treatment?
7
8. Overdose HistoryOverdose History
Time of ingestionTime of ingestion
Talk to witnessesTalk to witnesses
Get pill bottles &Get pill bottles &
count!count!
Assume commonAssume common
co-ingestantsco-ingestants
AlcoholAlcohol
AcetaminophenAcetaminophen
AspirinAspirin
Jmh649, Wikimedia Commons
8
9. DecontaminationDecontamination
GI exposureGI exposure
Most common route (75% of toxic exposures)Most common route (75% of toxic exposures)
Prevent absorptionPrevent absorption
Topical exposuresTopical exposures
Remove clothingRemove clothing
Wash skinWash skin
Enhance eliminationEnhance elimination
Whole bowel irrigationWhole bowel irrigation
SorbitolSorbitol
Diuresis / ion trappingDiuresis / ion trapping
HemodialysisHemodialysis
9
10. GI DecontaminationGI Decontamination
***Activated Charcoal******Activated Charcoal***
Absorbs up to 60% of ingestantAbsorbs up to 60% of ingestant
1 gm/kg +/- Sorbitol1 gm/kg +/- Sorbitol
Maximal effect if given early (<1 hr)Maximal effect if given early (<1 hr)
Will not bind – metals, electrolytes, acidsWill not bind – metals, electrolytes, acids
ContraindicationsContraindications
Depressed MS – Intubate to avoid aspirationDepressed MS – Intubate to avoid aspiration
Bowel obstruction / perforationBowel obstruction / perforation
Acid/ alkali ingestionAcid/ alkali ingestion
10
11. GI Decontamination –GI Decontamination –
Rare interventionsRare interventions
Gastric lavageGastric lavage
Early presentation of potentially lethal ODEarly presentation of potentially lethal OD
– e.g. tricyclics, iron, CCBs, B-blockerse.g. tricyclics, iron, CCBs, B-blockers
High Risk – aspiration / perforation / airway compromiseHigh Risk – aspiration / perforation / airway compromise
Syrup of Ipecac – Rarely used nowSyrup of Ipecac – Rarely used now
Induces vomiting & eliminates less than charcoalInduces vomiting & eliminates less than charcoal
Cardiomyopathy riskCardiomyopathy risk
Whole bowel irrigationWhole bowel irrigation
Sustained release preparationsSustained release preparations
Body packersBody packers
11
12. 2 am Toxicology Resources2 am Toxicology Resources
Poison ControlPoison Control
1-800-POISON11-800-POISON1
MicromedexMicromedex
General drug infoGeneral drug info
PoisindexPoisindex
OverdoseOverdose
managementmanagement
IdentidexIdentidex
Imprint identificationImprint identification
Parhamr, Wikimedia Commons
12
13. Treatment Goals with ODTreatment Goals with OD
ABCABC’s’s
Identify (if possible) substancesIdentify (if possible) substances
Reduce absorptionReduce absorption
Enhance eliminationEnhance elimination
Specific antidotes (if possible)Specific antidotes (if possible)
Relatively few but important to knowRelatively few but important to know
Supportive careSupportive care
13
18. Narcotics - treatmentNarcotics - treatment
Support ABCsSupport ABCs
Narcan 2mg IV q2min until effectNarcan 2mg IV q2min until effect
Comes in 0.4mg vials!Comes in 0.4mg vials!
Can require massive dosesCan require massive doses
IV / IM / SQ / ET routesIV / IM / SQ / ET routes
Short acting & may require repeatShort acting & may require repeat
doses or IV dripdoses or IV drip
18
19. SympathomimeticsSympathomimetics
Fight or flight systemFight or flight system
Drug activate adrenergic nervousDrug activate adrenergic nervous
systemsystem
Cross-activation of dopaminergicCross-activation of dopaminergic
euphoria & hallucinationseuphoria & hallucinations
19
23. Anticholinergic ToxidromeAnticholinergic Toxidrome
Antagonism of the cholinergic nervousAntagonism of the cholinergic nervous
system (parasympathetic)system (parasympathetic)
Sympathetic disinhibition & loss ofSympathetic disinhibition & loss of
parasympathetic functionsparasympathetic functions
Common medication side-effectCommon medication side-effect
Less commonly abused class of drugsLess commonly abused class of drugs
23
25. AnticholinergicsAnticholinergics
Blind as a bat (mydriasis)Blind as a bat (mydriasis)
Hot as hare (flushed & warm)Hot as hare (flushed & warm)
Mad as a hatter (delirium)Mad as a hatter (delirium)
Dry as a bone (membranes & axillae)Dry as a bone (membranes & axillae)
““Can’t see, can’t pee, can’t s—t, can’tCan’t see, can’t pee, can’t s—t, can’t
spit”spit”
25
31. Common CholinergicsCommon Cholinergics
OrganophosphateOrganophosphate
insecticidesinsecticides
Nerve gas (i.e. Sarin,Nerve gas (i.e. Sarin,
VX)VX)
Myasthenia GravisMyasthenia Gravis
medsmeds
““Green tobaccoGreen tobacco
sickness”sickness”
Nicotine poisoning duringNicotine poisoning during
harvestharvest
31
32. Cholinergics - TreatmentCholinergics - Treatment
ABCsABCs
DecontaminationDecontamination
Atropine 2 mg q 5 minutes untilAtropine 2 mg q 5 minutes until
secretions dry (massive doses)secretions dry (massive doses)
Pralidoxime (2PAM) ifPralidoxime (2PAM) if
organophosphatesorganophosphates
Supportive care / timeSupportive care / time
32
33. Case 1Case 1
2 yo M got into older sister2 yo M got into older sister’s medication.’s medication.
Mother brings to ED stating he’s had anMother brings to ED stating he’s had an
allergic reactionallergic reaction
P145 R25 T100.1 Skin flushed but noP145 R25 T100.1 Skin flushed but no
urticaria or rash. Seems to be picking at theurticaria or rash. Seems to be picking at the
air. Pupils dilated. Dry diaper.air. Pupils dilated. Dry diaper.
Nurses requesting Benadryl for his allergicNurses requesting Benadryl for his allergic
reaction.reaction.
Is this a good idea? WhatIs this a good idea? What’s going on?’s going on?
33
34. Case 1 contCase 1 cont
Anticholinergic toxidromeAnticholinergic toxidrome
SisterSister’s medication’s medication DetrolDetrol
AnticholinergicAnticholinergic
Benadryl also anticholinergic!Benadryl also anticholinergic!
Treatment?Treatment?
34
35. Case 2Case 2
15 people from a local government15 people from a local government
building with vomiting and weakness.building with vomiting and weakness.
2 patients with respiratory distress2 patients with respiratory distress
require intubation. Copious oralrequire intubation. Copious oral
secretions are noted.secretions are noted.
WhatWhat’s going on?’s going on?
35
36. Case 2 contCase 2 cont
Cholinergic toxidromeCholinergic toxidrome
SLUDGESLUDGE
Nerve gas / deliberate exposureNerve gas / deliberate exposure
1995 – Sarin in Tokyo subway1995 – Sarin in Tokyo subway
Treatment?Treatment?
36
39. AcetaminophenAcetaminophen
CommonCommon “cry for help”“cry for help”
UbiquitousUbiquitous
Accidental ODAccidental OD’s – “multi-symptom cold meds”’s – “multi-symptom cold meds”
Common co-ingestantCommon co-ingestant
Initially asymptomatic or mild GI upsetInitially asymptomatic or mild GI upset
Quiescent period of a few days afterQuiescent period of a few days after
intoxication (LFTs may be elevated)intoxication (LFTs may be elevated)
Delayed & sometimes fatal liver toxicityDelayed & sometimes fatal liver toxicity
39
40. AcetaminophenAcetaminophen
Metabolite toxic to hepatocytes causingMetabolite toxic to hepatocytes causing
hepatic necrosishepatic necrosis
At therapeutic doses, glutathioneAt therapeutic doses, glutathione
neutralizes metabolite and preventsneutralizes metabolite and prevents
toxicitytoxicity
At high doses glutathione depleted andAt high doses glutathione depleted and
toxicity resultstoxicity results
40
42. Specific intoxications: TylenolSpecific intoxications: Tylenol
The rule of 140The rule of 140
Toxic dose is 140 mg/kgToxic dose is 140 mg/kg
Toxic level at 4 hours is 140 mcg/mlToxic level at 4 hours is 140 mcg/ml
First dose of NAC is 140 mg/kg poFirst dose of NAC is 140 mg/kg po
(subsequent 17 doses are 70mg/kg)(subsequent 17 doses are 70mg/kg)
If 15 kg child, how many ES TylenolIf 15 kg child, how many ES Tylenol
pills (500 mg each) for toxic level?pills (500 mg each) for toxic level?
42
43. AcetaminophenAcetaminophen
Treatment: N-acetylcysteineTreatment: N-acetylcysteine
Replenishes glutathione in the liverReplenishes glutathione in the liver
Tastes AWFULTastes AWFUL
May require NGT administrationMay require NGT administration
Newer IV form (Acetadote – 2004)Newer IV form (Acetadote – 2004)
43
47. Specific intoxications:Specific intoxications:
SalicylatesSalicylates
General guidelines for severityGeneral guidelines for severity
Mild <300 mg /kg ingestedMild <300 mg /kg ingested
Moderate 300-500 mg/kgModerate 300-500 mg/kg
Severe / potentially lethal > 500 mg/kgSevere / potentially lethal > 500 mg/kg
Serum level > 30 mg/dl at 6 hrs - toxicSerum level > 30 mg/dl at 6 hrs - toxic
Done nomogramDone nomogram
Historical interest onlyHistorical interest only
Serum level not predictive of degree of toxicitySerum level not predictive of degree of toxicity
47
48. Salicylates - TreatmentSalicylates - Treatment
Increased elimination in urineIncreased elimination in urine
Urine alkalinizationUrine alkalinization
3 amps of bicarb in 1 L of D5W3 amps of bicarb in 1 L of D5W
Hemodialysis indicated ifHemodialysis indicated if
Coma, seizureComa, seizure
Renal, hepatic, or pulmonary failureRenal, hepatic, or pulmonary failure
Pulmonary edemaPulmonary edema
Severe acid-base imbalanceSevere acid-base imbalance
Deterioration in conditionDeterioration in condition
48
50. Tricyclic antidepressantsTricyclic antidepressants
Depression, sleep, & pain disordersDepression, sleep, & pain disorders
Less common due to SSRI prevalenceLess common due to SSRI prevalence
High toxicity in overdoseHigh toxicity in overdose
50
51. Tricyclic antidepressantsTricyclic antidepressants
Anticholinergic toxidrome plusAnticholinergic toxidrome plus
Cardiac DysrhythmiasCardiac Dysrhythmias
Quinidine-like (Ia) effects on Na channelsQuinidine-like (Ia) effects on Na channels
Sinus tach, Vfib, VtachSinus tach, Vfib, Vtach
SeizuresSeizures
51
52. Tricyclic antidepressantsTricyclic antidepressants
Screening EKGScreening EKG
Widened QRSWidened QRS
> 100ms – sz & dysrhythmia risk> 100ms – sz & dysrhythmia risk
R wave in aVR and S waves in I, aVLR wave in aVR and S waves in I, aVL
Prolonged QTcProlonged QTc
52
53. Electrocardiographic changes associated with tricyclic antidepressant
overdose. The QRS complex is prolonged with delayed right ventricular
activation and intraventricular conduction delay, which results in rightward
shift in the terminal 40 msec frontal plane QRS vector. In qualitative terms,
this shift manifests as a deep, slurred S wave in leads I and AVL, and an R
wave in lead AVR (blue arrows).
Source Undetermined
53
55. Case 3:Case 3:
27 yo F brought in by family. Confused27 yo F brought in by family. Confused
and vomiting.and vomiting. “She took some Tylenol“She took some Tylenol
this morning” (about 4 hours ago)this morning” (about 4 hours ago)
P125 BP135/65 T99.4 Warm, dry skin.P125 BP135/65 T99.4 Warm, dry skin.
Oriented x 2. Sometimes nonsensicalOriented x 2. Sometimes nonsensical
answers. +gag reflex. Dilated pupils.answers. +gag reflex. Dilated pupils.
What do you need to know?What do you need to know?
Does this fit with a Tylenol OD?Does this fit with a Tylenol OD?
55
57. Case 3Case 3
What are your initial orders?What are your initial orders?
Hint: ABC, IV, O2, monitorHint: ABC, IV, O2, monitor
What labs / tests do you want?What labs / tests do you want?
Medications?Medications?
57
58. Case 3Case 3
Acetaminophen level – 375 mg/dlAcetaminophen level – 375 mg/dl
What next?What next?
58
59. Case 4Case 4
32 yo M brought in because of violent32 yo M brought in because of violent
behaviorbehavior
Agitated and combativeAgitated and combative
P125 BP 160/95 T99.4P125 BP 160/95 T99.4
Warm & sweaty. Dilated pupils. ExamWarm & sweaty. Dilated pupils. Exam
otherwise non-focalotherwise non-focal
Differential?Differential?
59