Clinical Toxicology Lecture Notes PDF

Clinical Toxicology Emergency Toxicology-I ( Lab. III) 2nd Oct. 2024 5th Stage Dr. Ghazwan Ahmed Brifkani Ph.D. In Toxicology  Emergency Toxicology Principles in Management of Poisoned Patients: Necessary measures to prevent further deterioration of the...

Clinical Toxicology Emergency Toxicology-I ( Lab. III) 2nd Oct. 2024 5th Stage Dr. Ghazwan Ahmed Brifkani Ph.D. In Toxicology  Emergency Toxicology Principles in Management of Poisoned Patients: Necessary measures to prevent further deterioration of the patients; 1. Stabilization of the patient 2. Treatment of poisoning, 3. Administration of antidotes (specific antidotes or using the antidote cocktail). 4. Diagnosis of the poison, (poisons ID) 5. Continuing care and Prevention.  Emergency Toxicology 1- Stabilization of the patient (ABCDEs measures) A. Evaluation of Airway Obstruction Causes (Mucosal swelling, secretions, posterior displacement of the tongue and foreign bodies). Signs and Symptoms (Dyspnea, Dysphoria, Air hunger, Cyanosis, Diaphoresis and Tachypnea). Management & Measures: Clearing the airway, use of a nasopharyngeal tube (Intubation).  Cyanosis Cyanosis refers to the bluish skin color attributable most often to the presence of desaturated O2 < 85% and hemoglobin < 5g/dl in the arteries. Primary etiologies include respiratory, cardiac, circulatory, and nervous system disorders, as well as abnormal hemoglobin (central cyanosis). Acrocyanosis is a peripheral cyanosis around the mouth and extremities often seen in healthy newborns. http://easypediatrics.com/wp-content/uploads/2012/08/cyanosis-in-child.jpg  Emergency Toxicology B. Evaluation of Breathing (by ventilation and oxygenation) Causes (Respiratory depressant drugs, Pneumonia, Pulmonary edema, Lung abscess, Pulmonary emboli, Bronchospasm from numerous environmental & occupational sources and Tetanus). Signs and Symptoms (Tachypnea, Cyanosis, Hypoventilation and altered mental state). Evaluated by measuring of blood gases (CO2, O2), Chest X-ray. Management & Measures: Assisted ventilation and supplemental O2 delivered by nasal catheters and cannula).  Emergency Toxicology C. Evaluation of (C) Circulation Signs and Symptoms of inadequate tissue perfusion include shock (Depressed consciousness, Decreased blood pressure, Peripheral vasoconstriction, Metabolic acidosis, and Oliguria) Treatment (Position change, in case of low BP Vasopressors such as Dopamine, Norepinephrine, and Fluids).  Emergency Toxicology D. Evaluation of Depression (D) or Excitation (E) Depression is evaluated by (measuring the pupillary size, pupillary light reflex, motor responses to pain, and /or spontaneous eye movements). Excitation is manifested as seizures. Treatment of generalized seizures secondary to toxins (Diazepam, Phenobarbital, General anaesthesia, Enhancement of drug elimination by Haemodialysis).  Emergency Toxicology E. Cardiovascular CPR , maintain BP by using IV fluids (this would be the best option) Prevent arrhythmias This is a major symptom of poisoning, especially with Tricycle Antidepressants (block Norepinephrine reuptake with anticholinergic properties) Give IV sodium bicarbonate (NaHCO3), this may reverse an early arrhythmia The next agent of choice would be Lidocaine (IV injection) Procainamide anti-arythmic agent should be avoided due to its excessive cardiac depressant effect. 8  Advanced Cardiac Life Support (ACLS) Cardiovascular * ACLS established by the American Heart Association (AHA) & American College of Cardiology (ACC) * Used in all CV emergency * Try to maintain vital signs CV & Pulmonary. 1. Electric intervention 2. Mechanical - Cardiopulmonary Resuscitation (CPR) - Cardiac massage -Artificial Respiration 3. Drugs 9 Toxic ACLS – modified procedure for poisoning * In poisonings, resuscitation may exceed 20-30 min. * As a last resort, Doxapram may be used (0.5-1.5 mg/kg IV) to Stimulates respiration Is a respiratory stimulant which stimulates chemoreceptors in the carotid bodies of the carotid arteries, which in turn, stimulates the respiratory center in the brain stem. * 100% O2 >>> in acute CO intoxication about 4-5 hrs until the pait. is symptoms- free. * 95% O2 & 5% CO2 can be used with the majority of poisoned patients by CO. * CO has 250x more affinity to hemoglobin than O2 10  Emergency Toxicology 2. Treatment and prevention of poisoning A- Non ingested poison 1. Inhalation exposures Immediate, cautious removal of the patient from the hazardous environment. Administration of 100% humidified O2, assisted ventilation, and bronchodilators. Observe for edema of the respiratory tract and later non- cardiogenic pulmonary edema. Arterial blood gas assays, chest examination, and blood tests for the criminal substance (e.g., cyanide) should be performed. Treatment should not await laboratory results.  Emergency Toxicology 2. Dermal exposures Attendees should wear protective gear (gloves, gown, shoe covers). Remove the patient’s contaminated clothes, contact lenses, and any accessories (jewelry) immediately. Gently rinse and wash the skin with sufficient amount of water for at least 30 minutes. Do not use forceful flushing in a shower. Use slightly cold water and soap of oily substances. Toxic substances such as organophosphorous compounds, metal compounds, phenol, may penetrate the intact skin and must be handled with proper protective equipment. Apply medication  Emergency Toxicology 3. Ocular exposures Ocular decontamination consists of at least 15 minutes of immediate irrigation of eyes with normal saline or water. Alkaline or acid irrigating solutions should be avoided. Continue to irrigate the eye for as long as the pH is abnormal. Alkaline corneal burns are requiring ophthalmic consultation.  B- Ingested poison 1- Dilution of the poison with water. 2- Prevention of further absorption of poison. Induction of Emesis (Syrup of ipecac and Apomorphine) no longer recommended in many countries. Gastric lavage (nasogastric or an oro-gastric tube). Adsorption by activated charcoal (exceptions poisonings with heavy metals). Cathartics (hyper-osmotic saline, bulk-forming stimulant, and lubricant laxatives). https://www.youtube.com/watch?v=Abf3Gd6AaZQ https://www.youtube.com/watch?v=1OakmxZDa5c  Emergency Toxicology 3. Enhancement of elimination of absorbed poison. A. Forced diuresis (mannitol or furosemide) and pH alteration (NaHCO3). B. Extracorporeal techniques: Peritoneal dialysis (Diffusion of toxins from mesenteric capillaries across the peritoneal membrane into dialysate dwelling in the peritoneal cavity). Haemodialysis (Two catheters are inserted into the patient’s femoral vein. Blood is pumped from one catheter through the dialysis unit (a cellophane bag containing disposable filter and dialysate) and returned through the other catheter.  Emergency Toxicology Hemofiltration (Similar to hemodialysis, except that the blood is pumped through a hemofilter, where waste products and water are removed by hydrostatic pressure. Replacement fluid is added and the blood is returned to the patient). Hemoperfusion (The blood is withdrawn from the patient and passed directly over the adsorbing material (beads of charcoal or resins contained in a cartridge) contained in sterile columns to remove toxic materials). Plasmapheresis and Plasma exchange (separation of cellular blood components from plasma then cells are resuspended in fresh frozen plasma and reinfused again). Exchange transfusion (removal of the patient’s blood, replacement with fresh whole blood). Plasma perfusion (combination of plasmapheresis and hemoperfusion).  Emergency Toxicology 4. Inactivation of the absorbed poison (Antidotes). 1. Chelators as Deferoxamine, Dimercaprol, EDTA, Penicillamine. 2. Cyanide antidote as Dicobalt Edetate, Cyanide antidote kit (Amyl nitrite, Na nitrite, and Na thiosulphate), and Hydroxocobalamin. 3. Calcium salts such as Calcium gluconate and calcium chloride (hydrofluoric acid skin burns, neuromuscular paralysis, ingestion of fluoride salts, calcium channel blocker overdose, B-blocker overdose). I.V. Ca2+ gluconate should be given slowly. 4. Antivenins against spiders, scorpions, and snake bites. 5. 10% ethanol for methyl alcohol & Fomepizole (4-methylpyrazole: 4-MP) for Ethylene glycol.  Emergency Toxicology Homework: the following antidotes are used for toxicity of which drug/s with their mechanism of action? 1. Atropine 7. Naloxone 2. Flumazenil 8. Neostigmine 3. Methylene blue 9. Digoxin immune Fab 4. Pyridoxine 10. Protamine sulfate 5. Sodium bicarbonate 11. Dimercaprol 6. N-Acetyl-L-Cysteine 12. vitamin K Requirements: Mechanism of reversing toxicity (briefly). References. Subgroup submission (not individually). Deadline Thursday 3-10-2024. Some drug/antidote available in Azadi hospital- Duhok city N-Acetyl-L-Cysteine - 300mg, 600mg. Neostigmine Immunoglobulin f(ab')2 against Androctonus crassica uda scorpion venom, found in Middle East and Africa.  Nitroglycerin: venodilation, For angina pectoris Hydrocortisone, immunosuppressive drug, Anaphylaxis, allergic rash, etc. Dopamine: Inotropic agents Naloxone ,stimulant drug in the treatment of severe low blood pressure, slow heart rate, and cardiac arrest.  Flumazenil Protamine sulfate Potassium chloride: For Hypokalemia Digoxin immune Fab  Emergency Toxicology 3. The diagnosis of poisons Once the patient has been stabilized, the potential poison has to be identified. The diagnosis of poisoning involves the following; I. History given by the patient himself or relatives. II. Physical examination of the patient. III. Laboratory investigations.  Emergency Toxicology I. History Adults (Conscious or unconscious patients). Children (presence of traces, disintegrated tablets, abnormal behaviour or GIT disturbances). II. Physical examination of the patient (Blood pressure, pulse, respiration, temperature, eyes, mouth, skin, abdomen, nervous system). III. Laboratory investigations (Toxicant extraction from Urine, Blood, Hair, Saliva or Sweat samples, screening by thin layer chromatography (TLC), gas-liquid chromatography (GLC), and enzyme-mediated immunoassay techniques.