Poisoning Treatment Methods Quiz

General Toxicology

• Toxicology is the study of poisons on living organisms
• The term derives from Greek and Latin, with toxicum meaning poison and logia meaning study
• Toxicology encompasses the source, kinetics, action, diagnosis, and treatment of poisonings
• All substances are poisons, only the dose determines the effect
• Poisons are often classified by nature (solid, liquid, gaseous), site of action (local, remote), and target organ (e.g., gastrointestinal tract, kidneys, liver, central nervous system).

Classification of Poisons

• Nature: Poisons can be solid, liquid, or gaseous.

• Site of Action:

• Local: Inorganic corrosives

• Remote: Alkaloids and many therapeutics

• Local & Remote: Certain metals and organic compounds.

• Target Organ:

• Gastrointestinal (GIT): Metals and corrosives

• Kidneys: Mercury, phenol, cadmium

• Liver: Paracetamol, iron, carbon tetrachloride

• Cardiovascular System (CVS): Digitalis, aconitine

• Lungs: Metal fumes

• Central Nervous System (CNS): CNS stimulants (amphetamines, cocaine, strychnine) and CNS depressants (hypnotics, narcotics, alcohol, anesthetics)

Factors Modifying Toxic Effects

• Factors related to the poison:

• State of toxic agent: The dose of the poison, the route of administration (inhalation > intravenous > intraperitoneal > subcutaneous > intramuscular > intradermal > oral > topical)

• Cumulation: The rate of intake exceeding the rate of elimination (e.g., digitalis)

• Chemical interaction:

• Addition: Effects of chemicals combined (e.g., Aspirin + Paracetamol)

• Synergism: One chemical increasing another's effect (e.g., alcohol + barbiturate)

• Antagonism: One chemical reducing another's effect (e.g., BAL + lead)

• Metabolism: Some poisons are metabolized into equally or more/toxic substances (e.g., methanol to formaldehyde and formic acid)

• Factors related to the patient (Host factors):

• Gastrointestinal (GIT): pH of stomach and food type influence poison toxicity

• Age: Age can affect responses to poisons.

• State of health: Overall health can impact how a person responds to toxins

• Toxicogenetics (Idiosyncrasy): Unusual responses to drugs or toxic substances due to genetics. (e.g., favism, G6PD deficiency)

• Hypersensitivity (Allergy): Enhanced response to a substance (e.g. aspirin or penicillin) due to an antigen-antibody reaction

• Tolerance: Decreased response to a substance over time.

Diagnosis of Poisoning

• History: Sudden appearance of symptoms, symptoms in a group of people, history of poison purchase, or presence of suicidal notes
• Clinical Examination: Vital signs (BP, pulse, respirations, temperature), neurological examination, observation of chest, abdomen, skin, and breath odor, detection of signs and symptoms known as toxi-dromes
• Laboratory Investigations: Analysis of blood, urine, vomit, stool, hair, and nail (in living or dead individuals), and also ECG, EEG, electrolytes, blood gases, liver and kidney function tests

Postmortem Picture

• Stomach: Smell of substances like phenol, opium, organophosphates, cyanide, presence of ulcers for corrosives and tablets, identification of seeds/plants
• Skin: Eschar characteristics (e.g., black, yellow, white) and presence of injection sites
• Brain: Edema or congestion indicative of CO poisoning, signs of asphyxia
• Respiratory system: For signs of asphyxia

Coma and Poisoning

• Causes of Coma: Toxic causes (CNS depressants, anticholinergics, HCN, CO), pathological causes (hepatic, renal, metabolic issues, hypoglycemia, hypertensive encephalopathy), or traumatic causes (head injuries)
• Coma Scales:
• AVPU system: Alert, Verbal, Pain, Unresponsive. A rapid method for evaluating level of consciousness
• Reed's coma scale: More detailed evaluation of coma, used as an alternative to the Glasgow Coma Scale since it often provides a more accurate reflection of impairment

Treatment of Poisoning

• Supportive Therapy: Treating the patient, supporting ABCs (airway, breathing, circulation), and managing a patient's condition.

• Airway: Maintaining and securing the airway (e.g., positioning the head, using oropharyngeal airways, suctioning secretions, insertion of an endotracheal tube).

• Breathing: Providing supplemental oxygen (e.g., simple face mask, nasal cannula), mechanical ventilation if necessary

• Circulation: Treating hypotension (low blood pressure), managing cardiac arrhythmias, and fluid support.

• CNS: Treating altered mental status, providing dextrose, thiamine, and naloxone

• Gastrointestinal Decontamination: Removing or preventing the absorption of poisons from the gastrointestinal (GI) tract (e.g., emesis, gastric lavage, activated charcoal).

• Emesis: Inducing vomiting to remove substances from the stomach within 3 hours of ingestion

• Gastric lavage: Flushing the stomach with a solution to remove ingesting substances. Contraindicated with certain poisons.

• Activated charcoal: Absorbing poisons to prevent them from being absorbed into the bloodstream. Poisons poorly absorbed by this include Cyanide, heavy metals, alcohols, and others.

• Elimination of the poison from the blood (enhanced elimination): Methods include:

• Forced diuresis: Increasing urine output to excrete the poison. (using substances like Mannitol or a saline solution)

• Alteration of urine pH (ion trapping): Adjusting urine acidity to prevent the absorption of certain types of ionized substances/poisons into the bloodstream

• Dialysis (hemodialysis, peritoneal dialysis): Removing toxins from the blood when the kidneys cannot do so on their own.

• Hemoperfusion: Removal of certain toxins from the blood using a specialized filter (used for substances that aren't removed via dialysis)

• Plasmapheresis: Removing the plasma component of the blood, which can contain toxins/poisons.

• Antidotes: Specific substances used to counteract the effects of certain poisons. This may include chelators used to bind and remove specific ions to then be excreted in the urine.