Poison (Toxicant): any substance or agent capable of producing a deleterious response in a biological system or living organism. Poisoning= overdose toxicity intoxication= toxicity due to foreign substance
All substances are poisons: there is none which is not a poison. The right dose differentiates a poison from a remedy. Highly toxic chemicals can be life saving when given in appropriate doses. (Poisons are not harmful at a sufficiently low dose) An apparently non-toxic chemical can be toxic at high doses. (Too much of a good thing can be bad!). Synthetic does not mean toxic or poisonous Natural does not mean safe or even low risk
Poisoning episodes Accidental: Children less than 5 years by sugar coated tablets. Inhalation of organophosphorus pesticides. Overdose. Suicidal: in response to depression or specific life events. Homicidal Parasuicide: attention seeking behavior or attempt at suicide. It is typically classified as a low lethality method i.e. aim is not death
Injection: Routes of toxicant entry: Through cuts or hypodermic needles into the skin, usually cause highest blood conc Inhalation: Through mouth/nose into respiratory system, 2 nd Ingestion: highest blood level concentration. Through mouth into stomach and GIT, produces 2 nd lowest blood level. Dermal (Skin): By absorption through skin membrane, lowest in blood level
Management of Toxicity
Management Principles: 1 Immediate and supportive measures. 2 Absorption prevention. 3 Elimination of toxicant. 4 Specific antidote.
First: Ensure clear
First: Ensure clear = Airway = Breathing It is of 1 st priority = Circulation
Causes of air way obstruction: A=Air way Mucosal swelling. Increased salivation ( Conscious). Posterior displacement of the tongue. Swallowing of foreign bodies (ex: Fish bone).
A=Air way Symptoms of airway obstruction: Dyspnea. Air hunger. Hoarseness (stridor). Cyanosis. Diaphoresis. Drooling. Tachypnea.
A=Air way Management of airway obstruction: Head tilt and Chin lift maneuver. Jaw thrust maneuver.
A=Air way Management of airway obstruction: Nasopharyngeal or Oropharyngeal intubation
Management of airway obstruction: In case of comatosed patients: Cuffed endotracheal intubation is required to prevent aspiration because gag reflex is completely absent in unconscious patients
A=Air way Management of airway obstruction: Excessive mucosal secretions &/or salivation: Suction of excessive secretions by the aid of intubation. In Emergency Cases: Finally Emergency Cricothyrotomy.
Causes of respiratory depression: Drug-induced respiratory depression (Sedatives & hypnotic such as barbiturates & BDZs). Pulmonary edema & pneumonitis. Bronchospasm. B = Breathing
B = Breathing Management of respiratory depression: Give supplemental oxygen If necessary positive pressure ventilation artificial respiration Respiratory stimulants for severe respiratory depression
The shock is the clinical picture in which the patient shows signs of inadequate tissue perfusion. Symptoms of shock: C =Circulation SHOCK Coma
Management of shock: 1-Trendlenburg position. 2-Saline Infusion. C =Circulation
C =Circulation Management of shock: If the patient doesn't respond to 2L infusion & the signs of shock persist, the vasopressors should be used: 2-5 µg/kg/minute infusion up to 20 µg/kg/minute 3-vasopressors Dopamine Norepinephrine 0.1-0.2 µg/kg/minute. N.B. 1) Dopamine at low dose stimulates dopamine receptors renal & mesenteric vasodilatation. 2) Dopamine at medium dose stimulates cardiac β 1 receptors cardiac contractility & C.O.P. 3) Dopamine at high dose stimulates α 1 receptors systemic vasoconstriction.
After instituting ABC interventions, more detailed evaluation is required: Second: A. HISTORY: Collect any evidences (thrown tablets, empty bottles, any syringes, written notes.. etc).
After instituting ABC interventions, more detailed evaluation is required: Second: B. PHYSICAL EXAMINATIONS - Careful evaluation of S&S searching for toxidromes
TOXIDROMES It is a group of signs and symptoms and/or characteristic effects associated with exposure to a particular substance or class of substances. Use all your senses, search for the clues LOOK Pupil Size FEEL Temperature, Sweating SMELL Alcohol
After instituting ABC interventions, more detailed evaluation is required: Second: B. PHYSICAL EXAMINATIONS - Careful evaluation of vital signs (B.P, pulse, respiration, temperature): Hypertension Cocaine, amphetamines etc Rapid respiration Hypothermia Carbon monoxide. C.N.S depressants.
After instituting ABC interventions, more detailed evaluation is required: Second: B. PHYSICAL EXAMINATIONS Eye: - Pinpoint miosis is a typical sign of opioids toxicity. - Mydriasis is very common with cocaine. Mouth: - Ulcers/signs of burns with corrosives. - Bitter almond odor with cyanide toxicity. - Gingival lead lines with lead intoxication.
After instituting ABC interventions, more detailed evaluation is required: Second: B. PHYSICAL EXAMINATIONS Skin: Abdomen: - Cyanosis may be caused by airway obstruction and methemoglobinemia. - Hyperactive bowel sound, cramping and diarrhea are associated with arsenic intoxication.
2) Preventing absorption (Gut Decontamination) It is usually not effective more than 4-6 after poison ingestion. It is used only for orally ingested poisons. Methods of gut decontamination: Emesis Gastric Lavage Activated Charcoal Cathertics Whole Bowel Irrigation Most clinical toxicologists recommend administration of activated charcoal.
2) Preventing absorption (Gut Decontamination) For alert Pt Emesis Method: By the use of syrup of ipeca. The active ingredients are two alkaloids, emetine &cephaeline. Previous popular methods (fingertip stimulation, salt water, apomorphine) are ineffective. Dose: In children 5-15 ml ipeca syrup + 120 ml water. adults 15-30 ml ipeca + 240 ml water. The dose can be repeated if emesis has not occurred in 30 minutes. If vomiting does not occur gastric lavage or activated charcoal is decided.
2) Preventing absorption (Gut Decontamination) Complications: Lethargy Drowsiness Emesis Prolonged vomiting Diarrhea Contraindication: Children up to 6 months of age. Comatose patient because of increased risk of aspiration. Seizures (due to compromised gag reflex). Certain toxins: Hydrocarbons& volatile substances. Corrosives (Caustics). Ingestion of sharp objects.