Intro To Toxicology Flashcards
Define toxicology:
The science of poisons that study toxic substances.
Sources of toxins:
- Chemical (most common)
- Plant
- Animal (least but most serious)
Toxicant
Toxic substances from chemicals
Toixc substance from animals
Venom
Toxic substances that produced within living cell or organisms
Toxins: like bacterial toxins
Difference bt venomous and poisonous animals:
Venomous :deliver or inject their venom directly by apparatus (stinger)
Poisonous: don’t deliver it directly, thier entire body cantains toxic substance, it is harmful when it eaten or touch
Toxins sites action:
Local: corrosives
Systemic(remote): away from site of transmission
Both: oxalic acide (corrosive and reactive)
Factor effecting action of poisons
Realted to poison:
Dose
Physical statue : gas>liquid>solid
Purity: If impurities are more toxic than poison, more toxicity
Factor effecting action of poisons
Realted to poison:
Dose
Physical statue : gas>liquid>solid
Purity: If impurities are more toxic than poison, more toxicity
Factor effecting action of poisons
Realted to person:
Age: child and elderly more sensitive
Healthy: RF or LF
Sensitivity: genetic factors
Sex: female more sensitive (less mass and more fat)
Factor effecting action of poisons
Realted to mode or exposure:
Inhalation>i.v>i.p>s.c>i.m>i.d>oral
Factor effecting action of poisons
Environmental factors:
Temperature
Pressure
Humidity
Radiation
Toxidromes:
Signs and symptoms that related to specific poison
Definitive care of poisoning cases:
• Measure and identify the toxic agent
• Decrease further absorption
• Enhance elimination
• Antidote (if available)
• Treatment of systemic complications
The initial approach to poisoned patients should be essentially similar and every case end similar to:
Initial approach to the trauma patient
Components of the ABCDE approach:
Airways
Breathing
Circulation
Disability( level of consciousness)
Environment
The most common factor contributing to death from poisoning is:
Loss of airway-protctive reflexes with subsequent airway obstruction.
In poisoned patients, airway obstruction caused by:
- Flaccid tongue
- Aspiration of gastric contents
- Respiratory arrest
The most common cause of airway obstruction in unconscious patient is:
The first maneuver to manage it:
Passive obstruction by the tongue
Jaw thrust followed by endotracheal incubation
If the patient’s mental status is altered or if hypotension exists …give:
Coma cocktail:
100% oxygen
Naloxone
Glucose
Thiamine
Contraindications of induction of emesis:
Convulsions
Hydrocarbons
Corrosives
Sharp object (needle)
Come or decrease gag reflex
Less than 6m age (no gag relfex)
Hemorrhagic tendencies
Charcoal adult dose:
1mg/kg
Charcoal contraindications:
• Instestinal obstruction
• 3C:
Coma
Corrosives
HydroCarbon
• If you already gave Antidote
Can we use cathartics (laxatives) in poisoning management and why
Yes, they enhance the passage of material(toxins) through GIT and decrease the time of contact and absorption
Contraindications of laxatives:
Intestinal obstruction
GIT hemorrhage
Recent bowel surgery
Renal failure (of mg sulfate)
Name two types of laxatives with ex
Irritants that increase motility like caster oil
Osmotic that increases osmotic pressure like mg sulfate
Whole bowel irrigation used for:
Clean git from ingested non absorbed toxins
Indication of bowel irrigation
• material that is not absoped by charcoal
• massive amount
• sustained-release or enter-coated drugs
• packets of illegal drugs
What is antidote:
Therapeutic substance used to counteract the toxic action of specific xenobiotic
Classification of antidote according to mechanism of action:
A lot of talk
• intacts with poison to from non-toxic complex.
• accelerate detoxification.
• decrease the rate of conversion of the poison into its toxic mb
• Compete on the receptor
• block the poison’s receptor
• Bypass the effect of poison
• Antibodies to the poison
Example of antidote that bypass the effect of poison:
O2 in case of CO or cyanide toxicity
Example of antidote that competes the poison for its receptor:
Naloxone
Example of antidote that blocks poison receptor
Atropin in case of A large-scale exposure to a nerve agent or organophosphate insecticide or cholinergic syndrome
Example of antibodies antidote:
Digiband and antivenom
Example of antidote that decreases the rate of conversion of poison to ist toxic mb
Ethanol and fomepizole
Example of antidotes that accelerate detoxification of poisons:
N-actylecysteine and thiosulfate
Physical antidotes
Adsorbing: charcoal
Coating: mixture of egg and milk makes a coat over mucosa
Dissolving: 10% alcohol or glycerin for carbolic acid
Chemical antidote:
Oxidizing
Reduction
Precipitating
Example of oxidizing antidote:
Amyl nitrite is used in cyanide toxicity
Examples of reducting antidote:
• Vit c for drug causing Methemoglobinemia
• methylene blue for Methemoglobinemia producers
Examples of precipitating antidote:
Starch : it makes blue precipitate with iodine
Eggs, skimmed milk or gelatin : for mercury
Mention 2 methods to enhance the excretion of ABSORPED poisons
Manipulation of urine ph
Dialysis
Manipulation of urine ph by:
Forced alkaline diuresis
Acid diuresis (uncommonly)
Why is acid diuresis dangerous:
Because of the risk of myoglobin precipitation in renal tubules.
Dialyzable substances for good dialysis must have:
Low volume distribution
Low molecular weight
Low protein binding
Examples for dialyzable substances:
Alcohol
Barbiturates
Salicylate
Examples of non dialyzable substances:
Opiates
Atropine
Antidepressants
Peritoneal dialysis acts by:
Considering peritoneum as semi-permeable membrane
Complications of peritoneal dialysis:
Peritonitis
Perforation of abdominal organ
Dehydration or overhydraion
Intra-abdominal bleeding
