Toxicology Introduction- APX - SlideShare.pdf

toxin
medicine
antidotes
medicolegal duties of a RMP
duties of a doctor
management of a case of poisoing
sources of poisons
gastric lavage
ideal homicidal poison

1. AN INTRODUCTION
TO TOXICOLOGY
Dr Arun PinchuXavier
Assistant Professor
Dept: Of Forensic Medicine
SreeMookambikaInstitute 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 aspectsof 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 administeredinhaled 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:
MODEOF ACTION :
•Corrosive poisons
•Irritant poisons
•Systemic poisons
MOTIVE OR NATUREOF 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,
insecticidesCARDIAC
Digitalis
aconite
NEUROTIC
CEREBRAL-
Somniferous-Papaverum
Somnifera
Inebriants-alcohol
Deliriants-dathura
SPINAL–Strychnosnux
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:Mineralacids like -Sulphuricacid ,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:Oxalicacid ,carbolic acid

14. Fate of poison in body
•A part of poison when taken orally gets eliminated unabsorbed by means of
defecationand 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 .
•Liveris the main organ to detoxify or metabolizemost 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
poisonis
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 doseproduce 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 poisonouswhile 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 intramuscularlyor subcutaneouslyand
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 HOMICIDALPOISON..?

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 DDoI 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 homeostasisuntil
detoxification is accomplished and to prevent and treatsecondary 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
•Injectedpoisons:
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 removedand 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 usedif 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 amountof 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-
secreatedinto 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, Oesophagealvarices
•Procedure:
•Explainthe 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 intubationmust be done prior to lavage in case of relative
contraindications
•Head down position, left lateral side
•Lubricatethe 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:
•Physicalantidotes , 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 oppto
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 psychiatricassessment and regular
follow-ups.
•Prescriptions should be given for a limited supply of drugs.

41. Medico-legalduties of a doctor in suspected poisoning

42. Medico-legalduties 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,treatmentprogress any untoward outcome
04.Preservation :
All evidentiary materialspreserved , 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.

47. COLLECTION
OF PROPER
AUTOPSY
SPECIMEN IS
ESSENTIAL

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
•Stomachand 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. Stomachwith
contents
+
Proximal
30cm of Small
Intestines
+
Preservative
500gm of
Liverwith
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 2/3
rd
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:
Omissionto 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 -
[email protected]