Forensic Medicine & Applied Toxicology-1

Category: Education

Presentation Description

This is a presentation for forth year medical students and final year dental students at Moi University, School of Medicine


Presentation Transcript

Forensic Medicine & Applied Toxicology:

Death Investigation When Poisoning is Suspected The Basics and Medicolegal Obligations Examination of the Poisoned Victim By Dr. Willis Ochieng (Toxicologist) Forensic Medicine & Applied Toxicology

Questions to answer:

Questions to answer 2 Is this injury suspicious? Does the injury require forum for demystification? What is the mode and manner of injury?

Manner of Injury:

Manner of Injury 3 Manner Accidental Homicide Suicide Natural? Criminal Laws of Kenya

Mode of Injury:

Mode of Injury 4 Physical Chemical Sharp objects Blunt force Explosives & Guns Fire Water Drugs Corrossives Irritants Biotoxins Agrochemicals

Death Investigation When Poisoning is Suspected-1:

Death Investigation When Poisoning is Suspected-1 5 Investigation of poisoning cannot be done in isolation of the total death investigation T he principle governing the investigation is almost the same worldwide It is usually done under the jurisdiction of the local magistrate through the local police who is usually the investigating officer (IO ) in Kenya Kenya does not use a Coroner system The police who is the IO has a legal power to be assisted by experts he considers useful in the case Medical doctors, particularly pathologists , toxicologists often serve as part of the investigating team

Death Investigation when Poisoning is suspected-2:

Death Investigation when Poisoning is suspected-2 6 Not all deaths are subject to a legal investigation unless they are considered sudden, violent, unnatural, poisoning or unexpected Investigation must establish manner, mode and cause of death The cause of death may be an injury, intoxication or disease that initiates a process leading to death, and if that initial event had not occurred, the individual would not have died Death may follow years after the causal event In delayed deaths, is not easy in most cases to identify a toxicology issue The manner of death is circumstances in which the cause of death occurred and is classified as homicide, suicide, accident, natural and undetermined Classification of death is usually difficult as the anatomical findings elicited at autopsy are often insufficient to determine the manner of death

Death investigation when poisoning is suspected-3:

Death investigation when poisoning is suspected-3 7 Process of Investigation The IOs including community members are the eyes, ears and the mouth of the dead The doctor must speak the language of the dead through autopsy assisted by other experts Ideally, police reports and investigations should provide a reasonable amount of scene documentation This is not always the case In some countries, a doctor may be required to visit the scene

Death investigation when poisoning is suspected-4 Questions to answer:

Death investigation when poisoning is suspected-4 Questions to answer 8 It is not easy to identify a toxicology issue in illness or death Solution may be found by asking several questions Was death or illness due to poison ? What poison produced the illness? Was the substance suspected capable of producing death? Was sufficient quantity taken to produce death or toxic results? When and how was the victim exposed? Could poisoning have occurred and have become undetectable? Could the detected poison have an origin other than in poisoning? Was the poisoning suicidal, accidental or homicidal? Were the correct specimens collected, preserved and analysed in such a manner to answer the questions at hand?

Death investigation when poisoning is suspected-5 :

Death investigation when poisoning is suspected-5 9 Questionable deaths CPC lists death cases which may require a medico-legal investigation These are deaths- Where any form of violence, crime, suicide or accident was directly responsible or contributory Caused by an unlawful act or criminal negligence Occurring in a suspicious, unusual, or unexplained fashion Where there is no attending physician Of persons confined to a public institution Of any prisoner even though both the cause and manner appear to be natural Caused by or contributed to by drugs or chemical poisoning or overdose Of persons in apparent good health Occurring during diagnostic or therapeutic procedures (implied ) Of neonates born still in the absence of a physician Where there is insufficient medical information to explain the individual's demise

Medicolegal Obligations The State:

Medicolegal Obligations The State 10 The state has the constitutional and statutory obligation to protect her citizens under all circumstances A crime committed against another person or environment is a crime against the state The state has the responsibility to ensure that all deaths occurring have not been due to foul play and are natural

Medicolegal Obligations Medicolegal Obligations The Public:

Medicolegal Obligations Medicolegal Obligations The Public 11 The state fights crime and protects the public who intern is obliged to assist the police in an endeavour to control criminal activities A person (CPC sect 386 part 3), with any relevant information in any case or who finds a body or becomes aware of death of anybody shall immediately give information to the nearest administrative officer or police officer with the understanding of being a good citizen ( utumishi kwa wote  ) Assisting the Police to fight crime is equivalent to acting in self defence in its broadest sense Lack of civilian clarity of limit of public assistance has often led to the public taking the law into their hands, and dishing the punishment long before the police arrival  Kiswahili clause meaning “service for all”

Medicolegal Obligation The Police (PO) :

Medicolegal Obligation The Police (PO) 12 Enforcement and maintenance of law, peace and order Working arm of the government Which is often difficult to understand in most countries Responsibility to maintain peace makes the police naturally in charge of crime investigation CPC sect 386 part 2. On receipt of death— The PO in charge , or any other officer empowered by the minister shall proceed to the place where the body of the deceased person is, and shall there make an investigation D raw up a report on the apparent cause of death, describing such wounds, fractures, bruises and other marks of injury as may be found on the body, and stating in what manner, or by what weapon or instrument (if any), the marks appear to have been inflicted; and report to the nearest magistrate

Medicolegal Obligation The Doctor :

Medicolegal Obligation The Doctor 13 Doctors professionally, have no medicolegal obligation to assist the State to fight crime Medical expertise may be needed by the state in the course of administration of justice Under these circumstances, the doctor’s relationship with the State is contractual The doctor may be part of the investigation team in sudden , unexpected , violent deaths in order to determine actual cause and manner of death In poisoning cases, the doctor must both exclude traumatic or pathological mechanisms as possible causes, and select and preserve appropriate post-mortem specimens for toxicological analysis Certification of death

Medicolegal Obligations Toxicologist :

Medicolegal Obligations Toxicologist 14 Toxicologists are few worldwide and relatively fewer in most developing countries A lot of toxicological work is in the hands of other professionals without a broader and deeper understanding of the general science of poisons Not unusual to find a toxicological work being done at the corner of chemistry or biology laboratories The toxicologist provides some indication of what toxicological testing should be performed on suspicious cases

Toxicological Role in Homicide:

Toxicological Role in Homicide 15 Advise IO on suspicious cases Poisons are often used in homicide to cover murder brought about by other means Detect and quantif y certain drugs which may alter human behaviour making relationship between intoxication and violence an important factor Toxicological investigation in cases of traumatic homicide should always include tests for psychopharmacological agents particularly alcohol Assist in the interpretation of both negative or positive findings This may help explain how the victim became involved in a physical confrontation. Results of drug screening may provide information about the deceased's lifestyle Toxicological investigations may also reveal evidence that a victim was dragged to incapacitation and then murdered.

Toxicological Role in Suicides:

Toxicological Role in Suicides 16 Explain human interaction with poisons and vulnerable individuals Detect drugs that can exacerbate depression in suicides Drugs and common poisons found in suicide include alcohol, antimalarials , analgesics and benzodiazepines especially in Kenya Suicide by drugs or chemicals is still rare but is becoming important in towns and cities Pesticides particularly organophosphates and herbicides such as paraquat are commonly used in agricultural rural areas and most commonly used in suicide A determined suicide victim may often employ a multiple means to reduce the chances of survival A victim may take an overdose and either burn or shoot himself dead or jump into a deep river to drown Identify para -suicide cases The most frequent age is between 15 and 24 years and the frequency of attempt decreases with increasing age

Toxicological Role in Accidents-1:

Toxicological Role in Accidents-1 17 Ruling out poisoning in accidental deaths Accidents often result from carelessness of the victim or those who administer therapeutic drugs. Alcohol use is a major risk factor for accidental injury and death. However, when death occurs several hours after injury, ethanol in the blood may be absent or low. Suggest the best sample specimens Haematoma can provide additional information, which may not be derived by analysis of blood alone. Clots are structures, which are generally poorly perfused , and may reflect poison or drug concentrations much closer to the time of injury . Establish drug use prior to accident Blood clots may also be useful for documenting pre-existing drug use prior to hospital therapy as the drug concentration while protected from other possible contamination, will retain drug longer as a protected capsule.

Toxicological Role in Accidents-2:

Toxicological Role in Accidents-2 18 Toxicologist in collaboration with a doctor Doctor’s role at accident scene is twofold— Responsibility of treating the injured victims in non-fatal cases. Keeping good records for legal tussle which is likely to follow in all cases fatal What looks like an accident may not always be genuine When a driver becomes incapacitated by a heart attack, for example, and loss of control results in an accident Detection of poisons, together with other evidence, may indicate that an apparent accident was actually intentional Finding large quantities of a particular poison in a deceased person's stomach may suggest that an overdose was intentional rather than accidental If post-mortem investigation fails to detect carbon monoxide in the blood of a burned victim, or soot in the airway, It may be that the victim had already died when the fire started It may be natural or attempts to destroy evidence of a murder

Toxicological Role in Natural Deaths:

Toxicological Role in Natural Deaths 19 Toxicologist in collaboration with a doctor Toxicological investigation in apparent natural deaths may not be necessary if— Autopsy clearly reveals the cause of death No history of drug or alcohol misuse Toxicological analyses may be ordered to evaluate compliance in regards to the drugs used in treatment Toxicology screen may be of use when the apparent cause of death may be related to drugs, poisons or alcohol misuse Acute myocardial infarctions, ruptured berry and dissecting aortic aneurysms are often associated with recent cocaine use It is important to screen for drugs in the diagnosis of SIDS Child abuse can include drugging a restless infant, when even a small dose of drug may be fatal Toxicology screening is done to rule out poisoning by overdose when there is any uncertainty regarding the cause of death Unrecognised poisoning cases are sometimes discovered when samples for apparent natural deaths are submitted to the toxicology laboratory for testing

Toxicological Role in Unresolved Cases:

Toxicological Role in Unresolved Cases 20 Toxicologist in collaboration with a doctor Under the circumstances where the doctor cannot reach a convincing conclusion, poisoning becomes a strong suspect. When the cause and manner of death cannot be determined at the completion of investigations and autopsy, the case is left unclassified Under normal circumstances and with facility permitting, additional inquiries are initiated to find sufficient evidence for a diagnosis. The primary goal for the toxicology laboratory is to determine whether or not toxic substances are present in the deceased in sufficient quantities to kill. If a probable toxic cause of death is identified, the laboratory gathers additional evidence to indicate how it was administered, and how much was used, and time before death. The results of toxicology testing are used with other evidence to formulate an opinion regarding the manner of death.

Toxicological Examination of the Victim:

Toxicological Examination of the Victim 21 Begins with the preliminary identification of poisons found within the vicinity as well as those present in post-mortem specimens Confirmatory testing is then performed to conclusively identify the substances present Positive identification must be established by at least two independent analyses, each based on a different analytical principle Determine the quantity of poison in the appropriate specimens Poison quantification in specimens , as dictated by the case, provides more meaningful interpretative information If poisons are therapeutic drugs, their levels must be compared with established therapeutic and toxic ranges All cases cannot be tested for all drugs or poisons for many reasons one of which may be lack of adequate financial resources A number of factors determine what kind, and how many tests will be done Geographical patterns of poison distribution, drug use, occupation of the victim and laboratory capabilities must be considered Occasionally, a mere detection of a drug or poison is sufficient. But, in the case of some prescription medications, the actual amount present must be quantified

General Toxicological Screening-1:

General Toxicological Screening-1 22 Screening methods should provide presumptive identification , or at least class identification while also giving an indication of concentration An adequate screening protocol , capable of detecting or eliminating the majority of toxins, usually using three chemically unrelated techniques Some poisons are so common that, no matter the type of case, they should always be included for analysis; e.g., ethanol All screening positive tests relevant to the case must be confirmed, submitted for quantification in several tissues The reliability of the analytical outcome depends on the type of instrument and the personnel available in the laboratory

General Toxicological Screening-2 Intra-laboratory Case Review:

General Toxicological Screening-2 Intra-laboratory Case Review 23 Based on what is known about the death and the specimens available, a set of screening tests is designed to quickly detect or rule out the most common poisons or therapeutic drugs by a panel of analysts Review cases during toxicological investigation periodically Status evaluation and determination for need for additional testing Flow of information in forensic toxicology must be in two directions between the lab and the doctor who will integrate all of the findings The personnel must communicate with the doctor, suggest the proper selection of specimens, and assist with interpretation of the results Neither the doctor nor the toxicologist can be fully effective alone

The End:

The End

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