Definitions:
Toxicology
Is the study of poisons
Poisons
Any chemical agent that can
adversely affect the functioning of a
living organism.
Poisoning
Is an event which consists of damage
of the tissues due to exposure of the
individual to any chemical agent?
Aspects of toxicology:
Clinical toxicology
Diagnosis & treatment of
poisoning in living patient.
Forensic toxicology
Evaluating poisons as a cause or
a contribution to death.
Analytical toxicology
Is concerned with laboratory
investigation, both in living and
the dead.
*** The toxic and fatal dose: It is incorrect to believe that there is a fixed dose
for every drug or poison which will cause symptoms and disability and a larger
one which will kill as:
1.
2.
-
Different people have a wide range of sensitivity or resistance to a given
substance.
In the same person, responses may vary from time to time.
The concept of LD50 (the minimal lethal dose): it is a statistical tool, based on animal
experiments, being the dose which in a large series of tests would be expected to
cause death in half the test animals. However, some animals will be alive on far
higher dose than LD50, whilst others will have died at much lower doses. Thus, the
concept of LD50 cannot be used to predict the effect in humans.
Classification of poisoning
I- According to the nature of the poison
Solid
Liquid
According to the nature of poisons
Gaseous
II- According to the toxicity of poisons on organs
Cardiac Poisons
e.g. digitalis
Lung Poisons
e.g. irritant gases -(ammonia, chlorine)
Liver Poisons
e.g. phosphorus, acetaminophen
Kidney poisons
e.g. mercury
Gastrointestinal
tract e.g. heavy metals
poisons
C.N.S. C.N.S.
 Sedative hypnotics
depressants  Narcotics
 Alcohols
 General anesthetic
C.N.S
cocaine, amphetamine, strychnine
stimulants
III- According to the mode of action
Local action
e.g. corrosives
Remote action
e. g : Alkaloids (strychnine nicotine,
aconitine).
a- Narcotics.
b- Therapeutics.
Double action
Heavy metals, organic corrosives, NSAIDs
Diagnosis of poisoning
Toxidromes (a toxic fingerprint)
1. History
- Toxidrome is a collection of signs &
2.
Physical signs
symptoms that are observed after an
a) Clinical picture
exposure to a substance.
-
The symptoms and signs may
suspect poisoning but do not
give definite diagnosis. (May
resemble some diseases).
-
-
- Toxidromes are helpful in establishing a
diagnosis when the exposure is not well
known.
The following signs &
- Toxidromes include grouped
symptoms should at least
physiologically based abnormalities of
cause the doctor to include
vital signs, general appearance, skin, eyes,
poisoning in his first D. D.
m.m., lungs, heart, abdomen &
Sudden vomiting and
neurological examination that are known
Factors modify the action of poison:-
The doctor's duty in suspected poisoning
I- Related to the poison.
Whatever the cause or circumstances of poisoning
the doctor has a responsibility to manage the case
in most effective way.
1-Dose.
2-Route of administration
I.V., inhalation, I.M, S.C., ingestion, mm &
cutanous absorption.
3-State of the Poison
-Gaseous (rapidly absorbed and life
threatening) then liquid, then solid
poisons.
-Highly soluble concentrated poisons are
severely toxic.
4-Drug interactions: modification of the
effects of a drug by another chemical may be:
Antagonistic or synergistic.
May occur inside or outside the body.
II- Factors related to the patient
1- State of the stomach:
1- Diagnosis of poisoning at the earliest stage.
2- Treatment & admission to hospital if necessary.
3- Determine whether the poisoning Is →
→ Intentional (suicide or homicide).
→ Unintentional (accidental).
4- Send samples to toxicological analysis.
-Blood &urine are the first to be taken
-Establishing continuity of evidence.Page14
5- In case of homicidal tell the police and full
notification.
*Empty or full.
6- If the patient isn’t seriously ill and don’t want to
*Nature of contents.
*Secretion of the stomach HCL accuse anyone, doctor should respect his wishes
(achlorhydria
can
prevent KCN and don’t tell the police.
poisoning)
2- Age: Children & elderly are highly
susceptible to poisoning.
3- Health:
Healthy persons.
*Liver diseases: enhanced toxicity
*Kidney diseases: enhanced toxicity
*Pt e` mania is less affected by morphine
diarrhea
for many substances.
4-Tolerance
: reduction in response after
repeated
- administration.
Unexplained coma esp. in
5-Hypersensitivity : hyper response
children
6-Idiosyncrasy:
abnormal response
7- Genetic factors (e.g. (sulfonamides or fava
- Coma in adult known to have
beans can induce hemolytic reaction in
(G.6.P.D) deficiency.
depressive illness.
-
Rapid onset of a neurological
or gastrointestinally illness in
persons known to be
occupational!} Exposed to
chemicals.
b) Autopsy finding (in the dead)
usually unhelpful but may be
helpful in certain cases of
poisoning.
General management of poisoned
patients
(Treat the pt ,not the poison)
Manner of death from poisoning
1- Accidental:-common, may medicinal,
occupational or enviromental. e.g.


Children eating medicinal tablet.
Aggricultural poisoning via toxic insecticides.

Mass industrial disasters.
2- Suicidal most common bec. Toxic dugs are
easily obtained.
Paracetamol, barbiturates, agricultural insecticides
(parathion, phenol)
3- Homicidal; rare due to ease of detection.
arsenic, insulin, opiates are commonly used.
Management of poisoned patient with
normal mental status
1- Obtain & record the respiratory rate & rhythm,
vital signs (bl.P., pulse rate & regularity).
2- Proper clinical evaluation:
a- Medical history.
b- Toxicologic physical exam.
c- Lab investigations.
3- Decontamination: emesis, gastric lavage &
activated charcoal.
4- Antidotal therapy.
5- Symptomatic treatment e.g. agitation,
pulmonary oedema
General management of coma:ABCDE,CDAD
1-airway:1- Place the pt. in semilat. Position.
2- Pulling the tongue & supporting the jaw.
3- Frequent suction of secretions.
5- Emergent therapy:
a-
Seizures
1Benzodiazepines. e.g. 5-10 mg diazepam
(valium) I.V.
2Phenobarbital I.V. /15 min, is indicated to
treat seizures resistant to diazepam or status
epileptics.
4- Removal of any foreign body.
5- Cuffed endotracheal tube if necessary.
6- Tracheostomy (acuteU.R.obst) if E.T.I. fails
2- Breathing:-
3Muscle relaxant or general anesthesia (are
used if barbiturates fail)
bSevere metabolic acidosis: I.V. sod.
Bicarbonates.
1- Ventilation by nasal cannula or face mask or cmech. ventilation.
12- Perform arterial bl. gas (ABG) analysis.
2-
Cerebral edema:
3-
Hyperventilation.
3- Circulation:
1- I.V.line, start fluid therapy.
2- Vasopressors (if 1 fails) as dopamine.
Elevate the head of bed.
Use hypertonic mannitol.
6- Clinical evaluation:
3- E.C.G. monitoring (Control arrhythmia).
3-Lab investigation
4- Management of cardiac arrest (CPR).
1- Medical History
4- Drugs: (Empiric antidote)
2- Toxicological Physical Exam
Drugs should be used as diagnostic or therapeutic 7- Decontamination:
agents for comatosed pts within 1st 5 mints.
1- further drug absorption (gastric lavage,
1- Hypertonic dextrose:
A.charcoal & cathartics)
(D50W): 0.5- Igm/kg/adult.
(D10W): 0.5 -Igm/kg/child or
2- Drug enhanced elimination
8- Antidotal therapy
(D20W): 0.5 -Igm/kg/child
To diagnose & treat or to exclude hypoglycemia.
9- Disposition:
1- Mild cases:- hospitalization and monitored
2- Thiamine: 100 mg I.V. / adult (usually unnecessary
for a child) to prevent Wernicke's encephalopathy in
2- deep coma:- ICU, prevent sores, catheterization
alcoholics.
3- Naloxone: (5 ampoules, each 0.4 mg) 2mg I.V. for
adult & children with resp. compromise to
diagnose& treat (reversal of coma & C.P. dep) or
exclude (no effects) opiate overdose.
Reed’s grade
Toxicological physical examination
1-oropharynx manifestations:Characteristic smell,hypersalivation or dryness,
corrosives
Grade
of coma
Clinical Presentation
Grade 0
Sleep, patients are
arousable and answer
questions
Empty
obtain
bloods
Grade 1
Stupor,
patients
respond
to
painful
stimuli, gag reflex and
deep
reflexes
are
present, no respiratory
or
circulatory
depression.
Same as above,
plus start IV with
D5W
Grade 2
Coma, patients do not
respond
to
painful
stimuli, reflexes are
present, no respiratory
or
circulatory
depression.
Same as above,
plus insert cuffed
endotracheal
tube
Grade 3
Coma, patients do not
respond
to
painful
stimuli, reflexes are
absent, no respiratory
or
circulatory
depression
Same as group 2
Grade 4
Patients are in deep
coma, do not respond to
painful stimuli, absent
reflexes,
Place on volume
respirator,suction,
treat vital signs,
hem dialysis
2- Skin Manifestation
• Flushing, Cyanosed •Dry skin, Diaphoresis (excessive
sweating, signs of injury or injection.
3- Eye Manifestation:
Lacrimation, Conjunctival congestion, Nystagmus, Pupil
size, reactivity.
4- Chest:
Examination includes careful evaluation of lungs for
wheezing or bronchorrhea, Heart for rhythm, rate &
regularity.
5- Abdomen:
Bowl sounds, urinary retention, abdominal tenderness
or rigidity
6- Neurological examination
1- Determine the level of consciousness (AVPU: alert,
verbal response, painful stimuli response &
unresponsiveness) or Glasgow coma scale.
E + M + V (min:3 & max: 15)
E=eye opening
R.)
M= (motor R.)
V= (verbal
The pt. GCS will provide a useful measure of assessing
any changes in neurological status, but the GCS should
never be used for prognosis purposes because complete
recovery from properly managed toxic coma despite a
low GCS is the rule rather than the exception.
• Reed's classification of coma
Management
stomach,
baseline
Toxidromes (a toxic fingerprint)
- Toxidrome is a collection of signs & symptoms that
are observed after an exposure to a substance.
2- Extremities for tremors or fasciculation.
3- Cranial nerve, reflexes, resting muscle tone....
4- Caloric testing or testing for doll's eye (cervical spine
injury)
- Toxidromes are helpful in establishing a diagnosis
when the exposure is not well known.
- Toxidromes include grouped physiologically based
abnormalities of vital signs, general appearance, skin,
eyes, m.m., lungs, heart, abdomen & neurological
examination that are known for many substances.
Toxidrome
Representative
agent(s)
Most common findings
Additional signs and
symptoms
Potential interventions
Opioid
Heroin, morphine
CNS depression miosis,
respiratory depression
Hypothermia, bradycardia, Death
may result from respiratory arrest.
Putmonary edema
" Ventilation or naloxone
Sympathomimet
lic
Cocaine, amphetamine
Psychomotor agitation,
mydriasis, diaphoresis,
tachycardia hypertension,
hyperthermia
Seizures, rhabdomyolysis myocardial
infarction death may result from
seizures, cardiac arrest, hyperthermia
Cooling, sedation with benzodiazepines,
hydration
Cholinergic
Organophosphate insecticides
carbamate insecticides
Salivation, lacrimation,
diaphoresis, nausea, vomiting
urination, defecation, muscle
fasciculation, weakness,
bronchorrhea
Bradycardia, miosis/mydriasis.
Seizures, respiratory failure
paralysis
Death may result from respiratory
arrest 2o to paralysis and/or
bronchorrhea, seizures.
Airway protection and
ventilation, atropine, pralidoxime.
Anticholinergic
Scopolamine atropine
Altered mental status, mydriasis,
dry/flushed skin, urinary
retention, decreased bowel sounds,
hyperthermia, dry mucous
membranes
Seizures, dysrhythmias,
rhabdomyolysis.
Physostigmine (if appropriate)
sedation with benzodiazepines,
cooling, supportive management
Death may result from hyperthemia and dysrhyhmias
Salicylates
Aspirin oil of wintergreen
Altered mental status,
respiratory alkalosis, metabolic
acidosis tinnitus, hyperpnoea
tachycardia, diaphoresis nausea,
vomiting
Low-grade fever, ketonuria death
may result from pulmonary
edema, cardio respiratory arrest
MDAC. Alkalinization of the urine with
potassium repletion, hemodialysis,
hydration.
Hypoglycemia
Sulfonylureas, insulin
Altered mental status, diaphoresis,
tachycardia, hypertension
Paralysis, slurring of speech, bizarre
behavior, seizures. Death may result
from seizures, altered behavior.
Glucose containing solution
intravenously, and oral feedings
fable, frequent capillary blood for
glucose
Serotonin
syndrome
Meperidme
dextromethorphan + MAOI,
SSRI+TCA,
SSRI/TCA/MAOI+ am
phetamine, SSRI overdose
Altered mental status, in creased
muscle tone, hypcrreflexia,
hyperthermia
"wet dog shakes" (intermittent whole
body tremor). Death may result from
hyperthemia.
Cooling, sedation with benzodiazepines,
supportive management, theoretical
benefit-cyproheptadne