Toxicology Introduction- APX - SlideShare.pdf
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The document provides an extensive overview of toxicology, detailing the definitions, classifications, mechanisms of action, and management of poisonings. It covers the differences between poisons and medicines, the various types of toxic substances, and appropriate medical and legal responsibilities in cases of poisoning. Furthermore, it highlights care procedures, antidote administration, and legal documentation required during poisoning incidents.
Toxicology Introduction- APX - SlideShare.pdf
- 1. AN INTRODUCTION TO TOXICOLOGY Dr Arun Pinchu Xavier Assistant Professor Dept: Of Forensic Medicine Sree Mookambika Institute Of Medical Sciences
- 2. What is toxicology..? • Toxicology is the science which deals with properties, action, toxicity, fatal dose ,detection, estimation ,interpretation of the result of toxicological analysis of different toxins produced by plants, animals ,bacteria & fungi which are harmful to man • Forensic toxicology is a branch of Forensic Medicine dealing with medical and legal aspects of the harmful effects of chemicals on human beings
- 3. Is this , a medicine or a poison..?
- 4. Lets see, what a Poison is..? • Is a substance which, when administered inhaled ingested is capable of acting deleteriously on human body. • There is really no boundary between medicine and a poison because medicine in toxic dose is a poison and a poison in small dose may be a medicine • In law the real difference between medicine and poison is the intent with which it is given
- 5. Poison are classified accordingly to: MODE OF ACTION : • Corrosive poisons • Irritant poisons • Systemic poisons MOTIVE OR NATURE OF USE:
- 6. •MODE OF ACTION: 1. CORROSIVE POISONS these produce both inflammation and ulceration of tissues Alkalis NaOH ,KOH Metallic salts ZnCl2 , FeCl3 Acids Inorganic-HCL ,H2So4,HNO3 Organic acids- Oxalic , Carbolic acid
- 7. 2. IRRITANT POISONS These produces symptoms of pain in Abdomen Vomiting Purging Organic Vegetables- Ricinus,Abrus Calotropis Animals- Snakes, Scorpions,Spiders Mechanical irritants Glass ,Pin, Needles .. Inorganic Metallic – Arsenic ,Antimony Nonmetallic – Phosphorus Chlorine
- 8. 3.SYSTEMIC POISONS NEPHROTOXIC Cantherides HEPATOTOXIC Chloroform, Carbontetrachloride MISELLANEOUS Analgesics, insecticides CARDIAC Digitalis aconite NEUROTIC CEREBRAL- Somniferous-Papaverum Somnifera Inebriants-alcohol Deliriants- dathura SPINAL –Strychnos nux vomica PERIPHERAL-Conium REPIRATORY Carbon monoxide & dioxide
- 9. ABORTIFACIENT Ergot, Quinine Calotropis SUICIDAL Opium barbiturate ACCIDENTAL Aspirin OP STUPEFYING AGENT Dhatura Cannabis CATTLE POISONS Abrus Calotropis AGENTS CAUSING BODILY HARM Corrosive Acids Alkalis HOMICIDAL Arsenic Aconite Organophosphorus According to Motive Or Nature of use as:
- 10. Lets also see about: •Sources of poison: •Routes of administration of poisons •Mechanism of action of poisons: •Fate of poison in body •Excretion of poisons
- 11. Commercial poisons Agricultural poisons Industrial Sources Use of Drugs and medication Food and drink Miscellaneous Sources Domestic Household poison SOURCES OF POISON:
- 12. Introduction Inunction Routes of administration of poisons Injection Inhalation Ingestion
- 13. Mechanism of action of poisons: 1. Local action Acts only on the part with which it comes in contact Eg:Mineral acids like - Sulphuric acid ,Nitric acids 2. Remote Action Some poison act on being absorbed into the system by body. Secondary to absorption into the blood stream they cause systemic effects /organ damage Eg:Alcohol ,Opium 3. Combined Action Some poison have both local and remote action Eg:Oxalic acid ,carbolic acid
- 14. Fate of poison in body • A part of poison when taken orally gets eliminated unabsorbed by means of defecation and vomiting • Before absorption the poison may exert effects in GI tract • When absorbed ,the poison reaches different organs thru circulation but some may not cross tissue barrier • Major part is detoxified and than excreted after exerting its toxic effects on the body . • Liver is the main organ to detoxify or metabolize most of the poisons • Certain poisons like Choroform,Phosphrous Nitrates Acetic acid disappear by evaporation or oxidized in the body ,it may not even be detected in Post mortem if its delayed
- 15. Excretion of poisons Unabsorbed poisons are excreted through faeces vomitus Volatile poison is exhaled out Absorbed poisons excreted mostly by urine Some portion excreted by bile milk saliva sweat tear hair nails
- 16. CONDITION AFFECTING THE ACTION OF POISONS: • DOSE • FORM OF POISONS: • METHOD OF ADMINISTRATION • CONDITION OF THE BODY
- 17. CONDITION AFFECTING THE ACTION OF POISONS: DOSE • Small dose produce therapeutic action large dose produce toxic effects,however there are certain exception to this: • Idiosyncrasy – inherent intolerance -towards certain drugs and food • Allergy – Hypersensitivity • Habit- diminishes the effect of certain poisons, since a tolerance is gradually developed • Synergism – when two drugs in nontoxic doses are administered simultaneously ,their final response is equal to the sum of their individual actions • Some poisons(Arsenic Pb, Mercury) are eliminated slowly and may accumulate in the body Cumulative poisons.
- 18. FORM OF POISONS: • Physical state: Order of absorption -Gaseous and volatile poisons / Liquid / Solids . • Chemical combination: Toxic effects of substances may vary greatly from chemical combination. Some substances may become poisonous while some becomes inert. • Mechanical combination: The action of poison is considerably altered when combined with a inert substance
- 19. METHOD OF ADMINISTRATION: • A poison acts most rapidly when inhaled in gaseous or vaporous form or when injected intravenously next when injected intramuscularly or subcutaneously and least when swallowed . The action of poison is slowed down if : • Applied on unbroken skin • Presence of food in stomach • It is a partly soluble poison
- 20. CONDITION OF THE BODY: • AGE – Children and elderly are more susceptible to poisons Hepatic detoxification system are relatively underdeveloped in young children • STATE OF HEATH – ill health is likely to accelerate the effects of poisons • SLEEP AND INTOXICATION- Action of poison is delayed during sleep ,because of low metabolic activity
- 21. What’s a , IDEAL HOMICIDAL POISON..?
- 22. IDEAL HOMICIDAL POISON • Odorless Tasteless Colorless • Readily soluble in water as it allows for easy administration in normal foods drinks • Delayed onset of action • Low dose of lethality • Undetected in routine toxicological analysis • Easily obtained ,but not traceable, so that it will leave no investigative trail that would lead to the prisoner. • The poison should mimic a natural disease, as the poisoning will be missed
- 23. Management of a case of poisoning
- 24. DUTIES of a RMP in a case of poisoning: 1. Supportive care-maintain physiologic homeostasis 2. Prevention of further poison absorption 3. Enhancement of poison elimination 4. Administration of antidotes 5. Prevention of re-exposture MEDICOLEGAL duties of a RMP in poisoning : • Treatment • Intimation • Documentation • Preservation “ P C DDo I T ” • Consultation • Dying declaration & Death intimation
- 25. MANAGEMENT OF A CASE OF POISONING DUTIES OF A RMP IN A CASE OF POISONING 5 STEPS constitute the fundamentals of poisoning management 1. Supportive care 2. Prevention of further poison absorption 3. Enhancement of poison elimination 4. Administration of antidotes 5. Prevention of re-exposure
- 26. •01. SUPPORTIVE CARE The goal of supportive therapy is to maintain physiologic homeostasis until detoxification is accomplished and to prevent and treat secondary complications. This includes: • Airway protection • Treatment of arrhythmia • Oxygenation /Ventilation • Hemodynamic support • Correction of metabolic derangements • Prevention of secondary complications
- 27. 02. PREVENTION OF FURTHER POISON ABSORPTION –DECONTAMINATION • Inhaled poisons: Removing patient from the source Giving oxygen by mask • Contaminated eyes : Irrigating eyes with copious amount of plain water for 15-20minutes • Injected poisons: Application of tourniquets ,proximal to the point of injection may slow absorption
- 28. •Poisons acting locally : • Many substances ,such as Organophosphorus and Corrosives can be absorbed through skin and mucous membrane. • The affected cloths should be removed and the area should washed with copious amounts of water. • Chemical antidotes should not be used unless absolutely indicated. • Heat liberated during the chemical reaction may aggravate injury.
- 29. •Ingested poisons: ❖EMESIS Administration of a root of small shrub – Ipecac Acts by local activation of peripheral sensory receptors in GIT and by central stimulation of CTZ with activation of central vomiting center It can be induced by tickling the throat with fingers or oral administration of : • Common salt / Mustard / Tincture of iodine • Copper sulphate / Zinc Sulphate / Ammonium carbonate • Emesis should not be used if the patient has cerebral depression and in semi- conscious state as stomach contents may get regurgitated
- 30. GASTRIC LAVAGE / STOMACH WASH
- 31. ❖GASTRIC LAVAGE / STOMACH WASH Should be considered only if patient has ingested a life threatening amount of a poison and presents to the hospital within 1-3 hours of ingestion. Indications: • Ingested Unabsorbed poison presenting within 1-2 hours • In cases of parenteral poisons such as morphine, in which the poison get re- secreated into the stomach thru entero-hepatic circulation Contraindications: • Absolute : should never be undertaken at any circumstances ingestion of mineral acids except carbolic acid, owing to the danger of perforation. • Relative :GI can be done under protection of airways ,using cuffed ET Hemorrhagic diathesis, Coma, Esophageal varices
- 33. Gastric lavage … Contraindications: • Absolute : should never be undertaken at any circumstances ingestion of mineral acids except carbolic acid, owing to the danger of perforation. • Relative :GI can be done under protection of airways ,using cuffed ET Hemorrhagic diathesis, Coma, Oesophageal varices •Procedure: • Explain the procedure and get consent. • If refused better not to undertake ,because it amounts to an assault ,besides increasing the risk of complications due to active non-cooperation
- 34. Gastric lavage… Procedure… • Endotracheal intubation must be done prior to lavage in case of relative contraindications • Head down position, left lateral side • Lubricate the tube & insert via oral route ,the tube is passed into pharynx .and the patient is instructed to swallow Confirmation of the tube reaching stomach..? • The position can be checked either by air insufflations while auscultation over stomach ,or by aspiration
- 35. Special lavage solutions in different poisoning • Potassium permanganate – alkaloids salicylates • Sodium thiosulphate – cyanides • Castor oil and warm water – Carbolic acid • Calcium gluconate – Oxalates Lavage should be continued until no further particulate matter is seen, and the efferent lavage solution is clear Complications: • Aspiration pneumonia • Laryngospasm • Perforation of stomach and esophagus
- 36. ❖ACTIVATED CHARCOAL: • Fine odorless powder • It irreversibly binds the drugs within the bowel and reduces the blood concentration by reducing drug absorption and by creating a negative diffusion gradient between the gut lumen and blood • It reduces the systemic absorption of drugs like aspirin barbiturates..
- 37. •03.Enhancement of poison elimination: • Its based on rational understanding of drug properties and clinical condition of patient The various methods are: • Forced alkaline diuresis • Extracorporeal techniques ➢Haemodialysis ➢Haemoperfusion ➢Peritoneal dialysis ➢Hemofiltration ➢Plamapheresis
- 38. •04.Administion of antidotes: Therapeutic sub modify/counteract with clinical effects of particular toxic sub Universal antidote: Wide range of poisons Activated Charcoal 2 parts (Physical antidote ) + Magnesium Oxide 1 part (Chemical antidote ) + Tannic Acid 1 part (Precipitates poison) Antidotes are classified based on their mechanism of action: • Physical antidotes , Chemical , Physiological, Antagonistic • Competitive antagonistic antidote , Receptor antagonistic antidote • Antigen antibody reaction antidote
- 39. Receptor antagonistic antidote Atropine for ACH Physical prevents the action of poison mechanically Activated charcoal Chemical antidote Neutralizing and chelating BAL , EDTA Physiological Producing signs and symptoms opp to that produced by poison Naloxone, Neostigmine Antagonistic Diazepam Competitive antagonistic antidote It competes with the poison for the enzyme Ethanol with methanol Antigen antibody Digoxin specific antibodies
- 40. 05.Prevention of re-exposure: • Victims of accidental exposures should be instructed of safety measured and advised to avoid circumstances that result in poisoning • Depressed /Psychotic patients should receive psychiatric assessment and regular follow-ups. • Prescriptions should be given for a limited supply of drugs.
- 41. Medico-legal duties of a doctor in suspected poisoning
- 42. Medico-legal duties of a doctor in suspected poisoning: 01.Treatment : • The first and foremost duty is to safe the life of patient • Every hospital is under a legal obligation to treat to best possible extent and no case case be turned away on the pretext that the hospital is not authorized to handle MLC • If the facilities don’t exist for proper treatment ,the victims should be administered first aid /possible medical or surgical help possible before referring him ! • The treatment given must the one that has been approved by at least one of the school of thought • Over the phone consultations must be avoided
- 43. 02Intimation : • If a case of poisoning is accidental / suicidal in nature, the attending doctor working in private sector is under no legal obligation to notify the police. But a Government RMP has to report every case regardless of its nature. • If the patient dies, the police has to be informed. Death certificate must not be issued. • All cases of homicidal poisoning must be compulsorily reported to the police as per section 39 of CrPC. Failure to do so will make him culpable under Sec 176 IPC.
- 44. Intimation … • If the police require information on any case of poisoning which is either suicidal or homicidal in nature, the attending doctor has to divulge it. There is no scope for professional secrecy in such matters -175 CrPC. • If information is withheld or wrong information is provided, the doctor becomes culpable under section 202 and 193 IPC respectively.
- 45. 03.Documentation: • It is a good practice to document the findings in the case register • This document must contain all the important findings that have a bearing on the case like history ,manifestations, treatment progress any untoward outcome 04.Preservation : All evidentiary materials preserved , 3 GL wash samples, vomitus, fecal stain ,saliva Failure to do – Penalized under 201-IPC 05.Consultation: In case of doubt ,it is always good to have an expert opinion
- 46. 06.Dying Declaration: If the treating RMP anticipates such eventuality or if death is imminent still the victim is conscious and able to speak, it is preferable to call magistrate to record .If in case the treating RMP himself record 07.Death intimation: If the victim dies it is mandatory to inform the police regardless of the fact ,he being treated under Private / Government. In circumstances of death in case of poisoning ,death certificate should not be issued and body should be taken for medico-legal examination.
- 48. COLLECTION OF PROPER AUTOPSY SPECIMEN IS ESSENTIAL Ingested poison Poison reaches the stomach Absorbed into blood thru proximal part of small intestine Liver metabolizes and detoxifies the poison Excreted thru Kidney and urine
- 49. VISERA & BODY FLUID ROUTINELY PRESERVED • Stomach and its contents • Proximal 30cm of Small Intestines with its contents • 500gms of liver + Gall bladder • Longitudinal half of each Kidneys SPECIAL VISCERA • Narcotic drugs /Cyanide / Strychnine: Brain • Alcohol: Vitreous humor • Cardiac poison : Heart • Heavy metals: Long bone, 500 micrograms of plucked hair ,Finger / Toe nail • Snake bite / Injection sites: Subcutaneous tissue + underneath muscle and similar tissue from opposite side as control
- 50. Stomach with contents + Proximal 30cm of Small Intestines + Preservative 500gm of Liver with Gall bladder + half of each Kidney + Preservative 10-20ml of Blood preserved in sodium fluoride and potassium oxalate 50 ml of saturated sol of Common Salt / Sample Preservative used VISERA PACKING
- 51. PRESERVATIVES TO BE USED FOR VISCERA AND BODY FLUIDS • For Viscera: Rectified sprit / Common salt • For Blood: Venous blood sample – is Venepuncture of femoral vein Potassium oxalate (anticoagulant) 10mg/ml & Sodium fluoride (Enzyme inhibitor) 30mg/10ml • For Urine: Rectified sprit / Thymol crystals / Sodium fluoride
- 52. CONTRAINDICATIONS FOR USING CERTAIN PRESERVATIVES • Saturated Sodium chloride: Aconite poisoning, heavy metal poisoning vegetable poison and corrosive acids • Rectified spirit: Alcohol, acetic acid, carbolic acid, kerosene, paraldehyde & phosphorous
- 53. PACKING TIPS: • Stomach and intestines to be opened before packing • Kidney liver to be cut into pieces to ensure better penetration • Preservatives to be filled up to 2/3rd of bottle to prevent bursting FORWARDING SAMPLES • All samples should be properly sealed and labelled with name ,PM no ,nature of sample collection site preservative used date and time of collection • Handed over to be delivered to Forensic science laboratory /Regional forensic science laboratory for chemical analysis after obtaining proper receipt
- 54. LEGAL PROVISIONS
- 55. LEGAL PROVISIONS • SEC 176 IPC: Omission to Give notice / Information to a public servant is legally punished by simple imprisonment up to 6 months • SEC 201 IPC: Causing disappearance of evidence of an offence or giving false information to protect an offender – may be punished up to 7 years
- 56. MAY THE GRACIOUS GOD BLESS US ALL ALWAYS WISHING YOU ALL SUCCESS FOR YOUR UPCOMING EXAMS Your valuable suggestions are entertained - drpinchu89@gmail.com