Lec 1 Flashcards
What is a toxin?
Any poisonous substance of whatever origin that reacts with specific cellular components to kill cells, alter growth or development, or kill the organism.
How are poisons classified according to action?
- Local
- Remote
- Both
What are examples of inorganic corrosives?
- Sulphuric acid
- Hydrochloric acid
- Nitric acid
- Alkaline potash
What are the origins of poisons?
- Plant
- Animal
- Metallic
- Synthetic
Name a plant poison and its source.
Atropine from Datura
What are examples of selective organ toxicity?
- Hepato-toxins: Iron, Paracetamol
- Nephro-toxins: Mercury, Phenol
- Cardio-toxins: Digitalis, Quinine, Aconite
- Neuro-toxins: Amphetamines, cocaine, strychnine
What factors modify the actions of a poison in the body?
- Factors related to the poison
- Factors related to the patient
- Drug interactions
What are some factors related to the poison?
- Dose
- Form
- Concentration
- Route of administration
How does an empty stomach affect poison absorption?
It leads to rapid absorption.
What is tolerance in the context of toxicology?
Repeated use of the same dose will not produce the same effect, as in drug addiction.
What is idiosyncrasy in toxicology?
Abnormal response to drugs with a hereditary basis.
What are the components of supportive therapy in poisoning management?
- Airway management
- Breathing support (O2 therapy)
- Circulation monitoring
- CNS assessment
What is the purpose of the Coma Cocktail?
To treat comatose patients with dextrose, thiamine, and naloxone.
What does the primary assessment in poisoning cases involve?
Emergency management.
What should be included in the secondary assessment of poisoning?
- History and circumstantial evidence
- Clinical examination
- Investigations
What are some vital signs to monitor in poisoning cases?
- Blood Pressure
- Pulse
- Respiration
- Temperature
What is the anion gap?
The difference between the measured cations and anions in serum.
What are some methods of gastrointestinal decontamination?
- Emesis
- Gastric lavage
- Activated charcoal
- MDAC
- Cathartics
- Whole bowel irrigation
What contraindications exist for using emesis?
- Corrosives
- Coma
- Convulsions
- Chronic poisoning
- Cardiac and elderly patients
- Infants below 6 months
What is the primary use of activated charcoal?
To prevent the absorption of toxins.
What are some contraindications for using activated charcoal?
- Paralytic ileus
- Intestinal obstruction
- Drowsy patients without airway protection
True or False: Activated charcoal is effective in all types of poisoning.
False
What does the acronym MUDPILES represent in toxicology?
Conditions that may cause an elevated anion gap: Methanol, Uremia, Diabetic ketoacidosis, Paraldehyde, Iron, Lactic acidosis, Ethylene glycol, Salicylates.
What is the effect of Activated Charcoal on certain poisons?
Activated Charcoal is ineffective in which?
Activated Charcoal is ineffective in some poisons including:
* Cyanide and Corrosives
* Heavy metals (Iron, Lead, Arsenic, Mercury)
* Alcohols
* Rapid onset or absorption poisons (Cyanide, Strychnine)
* Chlorine and iodine
* Others insoluble in water
* Aliphatic and poorly adsorbed hydrocarbons
* Lithium
Activated Charcoal poorly adsorbs these substances, limiting its use in detoxification.
What are the disadvantages of Activated Charcoal?
Disadvantages include:
* Adsorbs oral antidotes
* May induce vomiting
* Mechanical obstruction of airways if aspirated
* Mechanical bowel obstruction with multiple doses
Antidotes should be administered 1-2 hours after charcoal to ensure effectiveness.
What are the indications for Multiple-Dose Activated Charcoal (MDAC)?
Indications for MDAC include:
* Enterohepatic circulation drugs (TCA, Digitalis, Barbiturates)
* Drugs that stick to the stomach (Salicylate)
* Slow gut motility (Barbiturates, Morphine)
MDAC enhances toxin elimination by creating a concentration gradient.
What is the typical dosing for MDAC?
Dosing for MDAC is:
* 0.5 – 1 gm/kg every 4 hours
* Continuous intra-gastric flow (0.25-0.5 gm/kg/hr) via Ryle tube
This method facilitates the removal of toxins from the plasma into the intestine.
What are common cathartics used in poisoning treatment?
Commonly used cathartics include:
* MgSO4
* Mg citrate
* Sorbitol
These agents help expedite the elimination of toxins from the gastrointestinal tract.
What are the contraindications for using cathartics?
Contraindications include:
* Paralytic ileus
* Intestinal obstruction
* Fluid overload in sodium-containing cathartics
* Renal insufficiency in magnesium-containing cathartics
These conditions can worsen with the use of cathartics.
What is Whole Bowel Irrigation?
Whole Bowel Irrigation is the irrigation of the entire GIT with non-absorbable isotonic electrolyte solution containing Polyethylene Glycol through a nasogastric tube
It is used to rapidly cleanse the bowel of poisons.
What are the indications for Whole Bowel Irrigation?
Indications include:
* Poorly adsorbed drugs by Activated Charcoal
* Slow-release drugs (e.g., Salicylates, Calcium Channel blockers)
* Expelling packets of illicit drugs (Body packers and Body stuffers)
This method is particularly effective for certain drug overdoses.
What are the general lines of poisoning treatment?
General lines include:
* Gastro-intestinal (GIT) decontamination
* Elimination of the poison from the blood
* Administration of antidotes
These steps are crucial in managing poisoning cases effectively.
What is the purpose of antidotes in poisoning treatment?
Antidotes are substances that oppose the effects of poisons without causing damage to the body
They can be local or systemic in nature.
What are local antidotes?
Local antidotes include:
* Physico-mechanical Antidotes: Adsorbents, Demulcents, Entanglers, Dissolvents
* Chemical Antidotes: Neutralization, Precipitation
These antidotes work at the site of the poison’s action.
What are systemic antidotes?
Systemic antidotes include:
* Physiological or pharmacological antidotes
* Chelating agents
They act throughout the body to counteract the effects of toxins.
Name a few examples of systemic antidotes and their corresponding toxins.
Examples include:
* Naloxone for Opiates
* N-Acetylcysteine for Acetaminophen
* Atropine for Organophosphorus poison
* Flumazenil for Benzodiazepines
These antidotes are critical in managing specific poisonings.
