Forensic Medicine & Applied Toxicology-8

Category: Education

Presentation Description

An outline of medical and legal intervention in suspicious cases of fatal poisoning. Ideal for senior medical students especially those in Kenya


Presentation Transcript

Medicolegal Intervention:

Medicolegal Intervention Dr. Willis Ochieng Toxicologist 09/09/2014 1

Medical Intervension:

Medical Intervension 09/09/2014 2

Medical Intervention Emergency Approach to the Poisoned Victim :

The management of acute poisoning remains an important part of accident and emergency care Because of the emergency nature, this may be the only time consent of the victim is immaterial prior to intervention Amidst all the confusions, the principal role of the doctor is to save life. All the necessary procedures must be instituted with immediate effect All the vital processes must be assessed and supported as necessary to stabilise the victim to allow for decontamination of the victim. The presence of all the normal vital signs does not mean the absence of poisoning Some toxins do not result in clinical manifestations until several hours after exposure They are five basic mechanisms for delayed toxicity These are: Delayed absorption, Distribution factors, Metabolic factors, Cellular and Organ capacity effects, and Unknown Scientific evidence for delayed-onset of effects varies considerably among the individual toxins Medical Intervention Emergency Approach to the Poisoned Victim 09/09/2014 3

Medical Intervention Decontamination Of The Intoxicated Victim:

Three gastric decontamination procedures have been widely used- Gastric lavage Emesis Use of activated charcoal Ipecac is effectively obsolete and gastric lavage has a narrow range of indications, principally for potentially serious amounts of agents not adsorbed by charcoal Protocols for care of the intoxicated patients should be modified accordingly The first thing to do is to remove the victim from the source of the poison Medical Intervention Decontamination Of The Intoxicated Victim 09/09/2014 4

Medical Intervention Measures to Reduce Absorption :

  After the patient has successfully vomited , or after the final gastric lavage , it is advisable to administer, orally or through the stomach tube, an adsorbent Some 30 minutes later, a laxative so as to diminish absorption of the poison and to accelerate its passage through the gastro-intestinal tract These measures can be supplemented by high enemas containing a contact laxative Medical Intervention Measures to Reduce Absorption 09/09/2014 5

Medical Intervention Adsorbents :

Activated charcoal possesses a non-specific capacity to adsorb a wide variety of chemicals Multiple-dose activated charcoal should be considered only if a patient has ingested a life-threatening amount Unless a patient has an intact or protected airway, the administration of multiple-dose activated charcoal is contraindicated Medical Intervention Adsorbents 09/09/2014 6

Medical Intervention Laxatives :

Laxatives and lavage solutions are used in the Treatment of constipation and toxic ingestion Preparation of the colon before endoscopic or surgical procedures Several different categories of agents are available for use-- Bulking agents Osmotic agents Secretagogues Agents with direct effects on epithelial nerve or smooth muscle cells Lubricating agents Each category has different pharmacological effects, side effects, and clinical indications Sodium sulphate has proved particularly effective Medical Intervention Laxatives 09/09/2014 7

Medical Intervention Enemas :

To eliminate remnants of poison from the lower segments of the gut, especially following administration of activated charcoal A high enema containing a contact laxative can be given about five hours after gastric lavage The enema may be repeated until the charcoal appears Use a suitable enema liquid such as warm soapy water, oil, lemon juice, etc according the case in question   Medical Intervention Enemas 09/09/2014 8

Medical Intervention Measures to Accelerate Elimination :

The choice of method will depend chiefly on type of poison , severity of poisoning , functional status of the kidneys , and patient's age Forced Osmotic Diuresis -- Electrolyte and sugar solutions containing osmotically active agents are infused Forced alkaline diuresis -- Electrolyte and sugar solutions are infused together with sodium bicarbonate Forced acid diuresis -- Infusion of electrolyte and sugar solutions, plus ammonium chloride to acidify urine Frusemide -induced diuresis -- Administration of strong and rapid-acting diuretic frusemide as an adjunct to the three types of diuresis listed above Medical Intervention Measures to Accelerate Elimination 09/09/2014 9

Medical Intervention Measures to Clean Blood Dialysis- Severe intoxication :

Indications for dialysis- Suspected patient has ingested and absorbed a potentially lethal dose Blood levels suggest that a lethal dose has been ingested Presence of high blood concentrations of a substance which is known to produce toxic metabolites Severe poisoning with a nephrotoxic or hepatotoxic substance which has already produced signs of organic damage Severe poisoning occurring in a patient in whom forced diuresis would be contra-indicated Severe poisoning in patients who are either very old or very young or in a poor general state Patient's condition progressively worsens in spite of intensive conservative treatment Severe poisoning associated with respiratory, cardiovascular, and renal insufficiency, hypotension despite fluid replacement, or persistent hypothermia Poisoning occurring in a patient already suffering from a serious disease Prolonged coma associated with a risk of pneumonia, septicaemia, or damage to peripheral nerves resulting from pressure-induced ischaemia Severe poisoning in which the EEG discloses no activity Medical Intervention Measures to Clean Blood Dialysis- Severe intoxication 09/09/2014 10

Medical Intervention Principles Of Antidotal Treatment:

Antidote may complex with poisons , rendering them inert. Arsenic, iron, mercury, lead, plutonium and uranium require chelating agents e.g. dimercaprol (BAL), calciumdisodium edetate (CDE), diethylene-triaminepentaaceticacid (DTPA) and penicillamine and many others Antidotes may block metabolic formation of poisons from less toxic precursors e.g. Methanol (ethanol), selenocystathionine ( cystine ), fluoroacetate (acetate ) Antidotes specifically may accelerate excretion of poisons e.g. Bromide (chloride), strontium and radium (calcium salts ) Antidotes may compete with poisons for essential receptors. Carbon monoxide (oxygen) , curare or tubocurarine ( neostigmine and edrophonium ), coumarin anticoagulants (vitamin K), morphine and related narcotics ( naloxone and related antagonists), thallium (potassium salts), amino acid analogs (amino acids ) Antidotes may block receptors that are responsible for toxic effects Cholinesterase inhibitors (atropine ) Antidotes may restore normal functions by repairing or by-passing effects of poison. Agents that produce methaemoglobinemia ( methylene blue), digitalis glycosides (potassium salts,  -adrenergic blocking agents and procaine amide), botulinus toxin (guanidine), methotrexate , other folic acid antagonists ( folinic acid), 5-Fluorouracil ( thymidine ), 6-Mercaptopurine ( purines )   Medical Intervention Principles Of Antidotal Treatment 09/09/2014 11

Medical Intervention Iatrogenic Toxicosis :

Avoid decisions as a result of pressure from relatives to evade making mistakes The intoxicated patient is a compromised one and may not handle standard doses of antidotes well due to toxicokinetic parameters Observe for toxic effects emanating from treatment and adjust dose appropriately Doses can be increased or reduced according to the pharmacokinetic parameters of the antidote and patient state Fluctuation parameter is controlled by the constant of elimination ( Ke ) Medical Intervention Iatrogenic Toxicosis 09/09/2014 12

Dose Regulation Computation Example:

Suppose you wanted to reduce the blood antidote level by 10% to avoid toxicity in a drug whose Ke =0.2 per hour The new dosing interval can be calculated using pharmacokinetic parameters as follows- 2.3log09 - ke   0.105 -0.2 0.53  (About 30 minutes) 09/09/2014 13 Dose Regulation Computation Example

Legal Intervention:

Legal Intervention 09/09/2014 14

Legal Intervention Legal Obligations :

Doctors trained by government sponsorship have medical obligation to the state and their patients This is no longer true in most African countries, because university medical education is now paid for by the parents A doctor called to certify death following a legal execution, has no medical obligation to do so unless he has signed a contractual agreement with the state All professional efforts directed at solving human or state medical problems , must be performed under the control of the law Purpose for this is to increase the benefits without infringing the rights of both the individuals and the society Medicine and Law are both viewed as interlocked institutions promoting and maximising the wellbeing of physical, emotional and community health Extent to which this is true is debatable The laws imposed on the medical practice without proper understanding, may lead to low achievement of the set goals The law can clash the doctor and the patient and erode the trust, which is the fundamental element in medical practice The trust requires that the doctor , the patient and community be aware of, and assume the obligations inherent in, their respective responsibilities, each understanding the other, each trusting the other, and both guarded by the law Legal Intervention Legal Obligations 09/09/2014 15

Legal Intervention The Rights Of The Patient/Victim :

The victim autonomy is the underlying ethical principle. Since the patient is responsible for her or his own health, he or she has the right to be adequately informed about the diagnosis, prognosis , and options for treatment The patient carries a responsibility to reflect the circumstances, symptoms, and events honestly and accurately and considers intelligently, in the context of trust, the recommendations provided by the doctor The doctor in turn is obligated to define and develop a course of therapy that he feels to be in the best interest of the patient under the circumstances manifested by the patient If the doctor discovers his or her limitation in the case, he or she must refer the patient to another doctor believed to have the relevant expertise There must be an atmosphere of honesty and trust that leads to both effective communication and understanding in both the patient and the doctor The one and the most important factor essential in boosting up the trust, effective communication and understanding, is confidentiality Doctors attending patients diagnosed with publicly dreaded diseases or the victims of crime , must know they have two responsibilities both as citizens acting within the context of legal justice system and as doctors attending patients If the legal system functions effectively and the doctors’ code applicable and consonant with the interests of the community, society and individual, then, there will be no conflicts between the two responsibilities There comes a time when the state or societal or community interest outweighs the individual interest threatening the confidentiality between the doctor and the patient Should a person with an infectious disease be exposed to the public in order to protect the society? Does the public have the right to know that a particular individual in a community has STI, AIDS virus or a criminal? Legal Intervention The Rights Of The Patient/Victim 09/09/2014 16

Legal Intervention The Rights Of the Unborn :

Freedom isn’t free . It is only free so long as it does not interfere with other people or the society A pregnant woman has no right poisoning her unborn baby The unborn is given a recognition as an individual separate from the mother within a society The society and the state may have a saying on prenatal toxicity and put a mother to task A woman with child has a moral societal responsibility for her foetus until birth Once pregnant, a woman has no right to poison or eliminate her unborn child The moment life is formed and can be shown by instruments like ultrasound, it must be accorded all the rights of a human being which makes its elimination a murder Many countries have laws which give the foetus little rights before viability age of 20 weeks which increases rapidly as pregnancy progresses Legal Intervention The Rights Of the Unborn 09/09/2014 17

Legal Intervention The Rights Of Witness or Suspect Under Influence Of Drugs  :

Many medicines are designed to affect brain or as side-effect . The effects depend on drug pharmacokinetics and pharmacodynamics An extensive range of effects on the brain can ensue, including effects on intellectual functioning, dexterity, memory, learning and subjective effects These medicines can be divided into- Those prescribed primarily to treat psychiatric disorders These include sleeping tablets, tranquillisers, antidepressants and antipsychotics. Those used to treat neurological disorders that have psychological side-effects Examples are anticonvulsants and anti- parkinsonian drugs Those used to treat non-nervous disorders that may have psychological side-effects Those obtained illegally and used in the non-medical context Drug-induced states that can influence testimony are mainly those causing sedation, disinhibition, paradoxical reactions and alterations in memory Courts observe the right of the suspect and ensure that suspect is in the best mental status to stand trial by ruling out the possible drug influence Legal Intervention The Rights Of Witness or Suspect Under Influence Of Drugs   09/09/2014 18

Legal Intervention The Rights Of Persons Under Control Of Others :

Employees under the control of their employers often require medical examination including workplace screening for alcohol and other drugs of abuse This raises many ethical issues If medical screening is considered as being part of medical practice with the involvement of occupational health physicians, then the ethical requirements of a normal medical consultation are fully applicable The employee's full and informed consent to the process must be obtained The employee should have an unfettered right of access to all the relevant records and to the sample specimens used If the process is not part of medical practice then employees should have the same rights as they would have if required to provide intimate body samples in the course of a criminal investigation, given the potentially serious consequences of an erroneous positive finding Legal Intervention The Rights Of Persons Under Control Of Others 09/09/2014 19

Legal Intervention Documentation :

A lot of data can be generated in forensic investigation. All this serve no good purpose to the courts if not recorded properly A well written statement may save a doctor a visit to court . Nevertheless , a personal presence can convey the careful accuracy of your work If you follow basic guidelines on statement writing the production of a good quality professional statement can implicate a criminal or exonerate an innocent suspect A doctor needs to see the medical evidence in perspective of other evidence in a case It is recommended that the examination record should be as detailed as possible to make it possible for a good statement to be written Legal Intervention Documentation 09/09/2014 20

Legal Intervention Documentation-1 Examination v Statement :

Examination Statements Notebook/file Statement form with declaration Not mandatory Full name (SURNAME) Not mandatory Qualifications Not mandatory Age / date of birth Not mandatory Personal details, initial paragraph Personal use, idiosyncratic For Police, Lawyers, Assessors, Judges Include technical terms Lay explanation (technical) Legal Intervention Documentation-1 Examination v Statement 09/09/2014 21

Legal Intervention Documentation-2 Examination v Statement :

Metric weights & lengths Common units Abbreviations Good plain English, properly constructed sentences Hand written Preferably typed Include history of event Refer to records Include medical history Refer to records Contemporary May be written months or years later Metric weights & lengths Common units Legal Intervention Documentation-2 Examination v Statement 09/09/2014 22

Legal Intervention Proceedings In Court:

All trials before the High Court are conducted with the aid of three assessors who must be between the ages of twenty-one and sixty Everyone can serve as an assessor except persons actively working as, priests or ministers of their respective religions , doctors , pharmacists , legal practitioners in active practice and persons disabled by mental or bodily infirmity The High Court may excuse an assessor from attendance at any particular sessions Assessors who have served in a trial may not to be summoned to serve again as assessors for a period of time All Kenyan residents have a national obligation to serve as assessors and need very good reasons not to do so on request by the court When the assessors have been chosen, the prosecutor will open the case against the accused person, and call witnesses and adduce evidence in support of the charge Legal Intervention Proceedings In Court 09/09/2014 23

Legal Intervention Presentation Of Expert Testimony:

Pre-Court Discussion Kenyan courts have no respect for time . It is suggested that you notify the court attendant that you have arrived It may also be necessary to do this yourself to avoid kitu kidogo  If possible, try to discuss your testimony with the prosecutor who has called you to court to resolve misunderstandings and misconceptions Because you are an impartial witness, permit the defence advocate to interview you if he or she so wishes. You are concerned only with justice and truth In Courtroom This is the day you must put on your best clothes. You must be conscious of your dress, appearance and bearing Stop trying to be what you are not. Display dignity, confidence, and humility during your presentation If you do not understand a question, or do not know the answer, say so. Do not try to give the impression that you know everything Combat the temptation to use technical terms. Speak good English without imitating an Englishwoman and without pride Never mix English with Kiswahili  during your presentation Do not be partisan in attitude Remember not to try the case, allow the prosecutor or defence advocate to do that Legal Intervention Presentation Of Expert Testimony 09/09/2014 24

Legal Intervention Delivery Of Expert Testimony :

First you must take an oath before witnessing otherwise your evidence will not be admissible. The prosecutor (examination-in-chief) then will establish voir dire (to see, to hear, to speak the truth) to introduce you to assessors and Judge This is done by being asked a series of questions whose answers will determine whether or not you are an expert witness A doctor appearing in court for the first time does not have the advantage of this but you have to start somewhere You will be asked about procedures and how you formed an opinion in the case by the prosecutor. This will be followed by the defence advocate (cross-examination ) whose principal aim is, usually and not always, to discredit your findings Do not lose your temper . Try your best to convey an attitude of independence to avoid personal involvement during the cross examination Re-examination by the prosecutor may follow to clarify issues arising during cross-examination. Re-cross examination may follow that of the prosecutor by the defence advocate, perhaps with the purpose of obliteration of facts It is up to the Magistrate or Judge to sort it out . The Judge can ask any question to any witness at any time during the court process With all the hustles, do not be disappointed if the court entered a nolle prosequi  after putting a lot of effort in the case Legal Intervention Delivery Of Expert Testimony 09/09/2014 25

The End:

The End 09/09/2014 26

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