بنام خداوند بخشنده مهربان

1. بنام خداوند بخشنده مهربان

2. دكتر فرزاد قشلاقي متخصص طب قانوني و مسموميتها دانشِار دانشکده پزشکی E. mail:gheshlaghi@med.mui.ac.ir Forensic Toxicology

3. Introduction to Toxicology

4. Toxicology What is toxicology? The study of the effects of poisons. Poisonous substances are produced by plants, animals, or bacteria. Phytotoxins Zootoxins Bacteriotoxins Toxicant - the specific poisonous chemical. Xenobiotic - man-made substance and/or produced by but not normally found in the body.

5. Introduction Toxicology is arguably the oldest scientific discipline, as the earliest humans had to recognize which plants were safe to eat. Most exposure of humans to chemicals is via naturally occurring compounds consumed from food plants. Humans are exposed to chemicals both inadvertently and deliberately.

6. History 2700 B.C. - Chinese journals: plant and fish poisons 1900-1200 B.C. - Egyptian documents that had directions for collection, preparation, and administration of more than 800 medicinal and poisonous recipes. 800 B.C. - India - Hindu medicine includes notes on poisons and antidotes. 50-100 A.D. - Greek physicians classified over 600 plant, animal, and mineral poisons.

7. History 50- 400 A.D. - Romans used poisons for executions and assassinations. The philosopher, Socrates, was executed using hemlock for teaching radical ideas to youths. Avicenna (A.D. 980-1036) Islamic authority On poisons and antidotes. 1200 A.D. - Spanish rabbi Maimonides writes first-aid book for poisonings, Poisons and Their Antidotes

8. History Swiss physician Paracelsus (1493-1541) credited with being “the father of modern toxicology.” “All substances are poisons: there is none which is not a poison. The right dose differentiates a poison from a remedy.”

9. The Dose Makes the Poison An apparently nontoxic chemical can be toxic at high doses. (Too much of a good thing can be bad). Highly toxic chemicals can be life saving when given in appropriate doses. (Poisons are not harmful at a sufficiently low dose).

10. HistoryItalian physicianRamazzini (1713) published“De Morbis Artificum” (Diseases of Workers) describing "asthma" in bakers, miners, farmers, gilders, tinsmiths, glass-workers, tanners, millers, grain-sifters, stonecutters, ragmen, runners, riders, porters, and professors. Ramazzini outlined health hazards of the dusts, fumes, or gases that such workers inhaled. The bakers and horse riders described by Ramazzini would today probably be diagnosed as suffering from allergen-induced asthma. The lung diseases suffered by most of the other workers would now be classified as "pneumoconiosis," a group of dust-related chronic diseases.

11. History Spanish physician Orfila (1815) established toxicology as a distinct scientific discipline.

13. Forensic Toxicology

14. Forensic Toxicology • Toxicology is defined as the study of the adverse effects of chemicals on living organisms. • Forensic toxicology is defined as the application of toxicology for the purposes of the law.

15. History • Ancient Egyptians and Grecians reported poisonings due to herbs, plants and food. • Opium, arsenic and hydrocyanic acid were used throughout Europe during the middle ages.

16. History • Philippus Theophrastus Aureolus Bombastus von Hohenheim (or Paracelsus) observed that any substance could be a poison, depending on its dose • “ What is there that is not poison? All things are poison and nothing without poison. Solely the dose determines that a thing is not a poison”

17. Paracelsus (1493-1541), more properly Phillippus Theophrastus Aureolus Bombastus von Hohenheim, was born in Einsiedeln, Switzerland in 1493, one year after Columbus' first voyage to the New World. He was a contemporary of Copernicus, Martin Luther, Leonardo da Vinci and a host of other figures we associate with the shattering of medieval thought and the birth of the modern world.

18. History • In 1814, M.J.B. Orfila, the chairman of the legal medicine department at the Sorbonne in France, published a book entitled Traite des poisons ou Toxicologie Generale.

19. This was the first attempt to systematically study and classify poisons. Six classes of poisons were established, based mainly on their toxic effects. He also isolated arsenic from a variety of postmortem specimens and was the first to articulate the fact that poisons must be absorbed, or enter the blood, to manifest their toxic effects.

20. History • In 1851, Stas developed the first effective method for extracting alkaloids from biological specimens. • This was modified several years later by Otto, which enabled the isolation of purer alkaloid substances. • This became known as the Stas-Otto method and remains the basis for drug extraction to this day.

21. In the U.S., forensic toxicology did not develop until the early 20th century. • In the U.S., forensic toxicology did not develop until the early 20th century, with the change of the coroner system in New York to a medical examiner system. The first forensic toxicologist was Dr. Alexander Gettler, who directed the laboratory for 41 years and trained the first generation of forensic toxicologists in the country. • Dr. Alexander Gettler is considered this country’s first forensic toxicologist.

22. Forensic Toxicology • Postmortem forensic toxicology. • Human performance toxicology. • Forensic drug testing.

23. Outline • Definitions and purpose of postmortem tox • Samples of forensic interest • Handling and storage of samples • Pitfalls in postmortem toxicology • Interpretation of results

24. Postmortem Forensic Toxicology • Death Investigations(Medicolegal sys.) • Coroner • Medical Examiner • Continental • A coroner may be elected by the people or appointed by a governmental authority. A medical examiner is appointed, usually by the health department. A coroner is not required to have any particular training or experience in medicine. Conversely, a medical examiner must be a physician, usually a pathologist, with specific training in forensic medicine

25. Postmortem Forensic Toxicology • Qualitative and quantitative analysis of drugs or poisons in biological specimens collected at autopsy • Interpretation of findings in terms of: • Physiological effect at time of death • Behavioural effect at time of death

26. How might one define postmortem forensic toxicology? • The purpose of postmortem forensic toxicology is to perform qualitative and quantitative analysis for drugs and their metabolites, and poisons such as metals, carbon monoxide, and volatile substances in human fluids and tissues collected after death.

27. Quantitative vs. Qualitative • Qualitative analysis – determines the presenceor absence of a drug or poison in a submitted sample • Quantitative analysis – determines the amount of drug or poison that is present in the submitted sample

28. Postmortem Forensic Toxicology Types of cases: • Suspected drug intoxication cases • Fire deaths • Homicides • Driver and pilot fatalities • Therapeutic drug monitoring • Sudden infant death (SIDS)

29. These are the types of cases that typically fall into the realm of postmortem forensic toxicology. • Unexplained deaths, with no apparent cause (often suspected to be drug intoxication cases) as well as those that are strongly suspected of being drug intoxication cases. • Fire deaths – measurment of toxic gases such as carbon monoxide and cyanide which may be inhaled during a fire. Furthermore, drugs may be implicated as having incapacitated a victim, thereby preventing their escape from a fire. • Homicides – homicidal poisonings themselves, are rare – but many homicide cases are related to drug use and drug abuse. • Driver and pilot fatalities – where drug impairment may help determine the cause of a crash. Other traumatic causes of death will also require postmortem toxicology analysis (such as drownings, falls) • Therapeutic drug monitoring – for example, determining whether an individual with a seizure disorder has been compliant in their medication use. • SIDS – by definition, SIDS is a diagnosis of exclusion. Therefore, toxicology must be comprehensive in these case to rule out any other cause of death.

30. Issues in Specimen Collection • Selection • Multiple, varied sites of collection • Collection • Appropriate method of collection • Adequate volumes for analysis • Storage and handling Important to ensure analytical results are accurate and interpretations are sound

31. Samples of Forensic Interest

32. Typical autopsy specimens • Blood • Urine • Stomach contents • Bile • Liver • Hair • Vitreous humor

33. Blood • Antemortem  ideal blood sample • Postmortem blood is not truly “blood” • Anatomical site of collection at autopsy should be noted

34. Subclavian Heart • Central sites • Heart • Peripheral sites • Femoral • Iliac • Subclavian • Other sites • Head blood • Hematoma blood Iliac Femoral

35. Ideally, blood should be collected from both a central site, such as from the chambers of the heart – in addition to one or more samples being collected from a peripheral site. • The most common peripheral sites of blood collection are femoral, iliac, and subclavian (emphasis on femoral). • “Head blood” – rarely seen in adults, but is not an uncommon site of selection in babies, especially since in infants it is difficult to obtain blood from the peripheral sites and blood volume of the heart is small. • Hematoma blood –

36. Hematoma • Extravascular blood clot • Protected from metabolism • Analysis will indicate what drugs were present in the blood at the time of formation • Analysis of hematoma blood has has proven especially useful with alcohol…

37. Hematoma case example • A 62year old man was found dead at the bottom of a staircase. Death was due to physical injuries. • Question as to alcohol use prior to fall down stairs • No urine available at autopsy • Alcohol not detected in femoral blood • Alcohol in hematoma blood  150 mg/100 mL • The deceased had been drinking prior to receiving the head trauma. • The deceased had survived for several hours after the injury.

38. Hematoma • Caution: There may be a delay between the incident which resulted in hematoma and the actual formation of the hematoma • Therefore, this alcohol concentration does not necessarily indicate the BAC at the time of the fall down the stairs.

39. Urine • Produced by the kidneys • Blood filtered by the kidneys • Stored in the bladder until voided • Qualitative - the presence of a drug in the urine of an individual indicates that some time prior to death the drug or poison was present in the blood of the individual • It simply means that some time prior to death the drug or poison was present in the blood. • urine analysis – in isolation of blood analysis is of limited value.

40. Stomach contents • Visual examination may reveal tablets • Drugs that have been orally ingested may be detected in stomach contents • Caution: drugs administered by other routes may also diffuse into stomach contents from the blood(pH gradient) • Generally qualitative: • Stomach contents are not homogeneous • Only a portion of stomach contents collected (unmixed?) • Useful for directing further analysis

41. Case Example • A 62 year old woman is found dead in bed • Numerous medications in her home: • Amitriptyline, Oxycodone, Morphine, Paroxetine, Diphenhydramine, Pseudoephedrine, Phenobarbital, Codeine, Temazepam, Diazepam • Only 3 mL of blood collected at autopsy • Qualitative analysis of stomach contents: • Amitriptyline: detected • Nortriptyline: detected • Quantitation can now be performed in blood

42. Liver • Drug metabolism occurs in the liver • Both parent compounds and metabolites may be present in higher concentrations in the liver than in the blood  ease of detection • Limitation is that drugs are not uniformly distributed throughout the liver  confounds interpretation

43. Bile • Digestive secretion • Continuously produced by the liver • Stored in the gallbladder • Qualitative - the presence of a drug in the bile of an individual indicates that sometime prior to death, the individual was exposed to the drug

44. Vitreous humor • Fluid that occupies the space between the lens and the retina of the eye. • Sequestered from putrefaction, charring and trauma, microorganisms. • Useful in cases where decomposition is advanced, body is exhumed or in fire deaths • Limitation is blood:vitreous ratio may not be known

45. Hair • Recent specimen of interest • Metabolism does not occur in hair • Can provide a historical record(generally 1 cm/month) of drug or poison exposure • Pros and cons of hair analysis still being uncovered  racial variability?

46. Case Example • 70 year old woman, previously in good health • Nausea, vomiting, diarrhea, rash, fever • Weakness in hands and feet  Guillian Barre? • Hospitalized with hypotension, seizures • Misplaced laboratory result  Arsenic! • Sequential hair analysis for arsenic showed chronic arsenic poisoning over 8 month period

47. Non-biological submissions • Used to direct analysis of biologicals • May indicate the nature of substances that may have been ingested, inhaled or injected • Examples: • Containers found at the scene • Syringes • Unidentified tablets or liquids

48. Autopsy specimens of limited value • Pleural fluid • Chest cavity blood • Gutter blood • Samples taken after embalming • Samples taken after transfusion in hospital • “Spleen squeezings” • “Esophageal scrapings”

49. Chest Cavity Fluid • Not readily definable • Most likely to be collected if: • Traumatic injury to the chest • Advanced decomposition • A “contaminated” blood sample, chest cavity fluid may contain fluids from stomach, heart, lungs etc.

50. Samples taken after embalming • Methanol is a typical component of embalming fluid • Most drugs are soluble in methanol • Embalming process will essentially “wash” the vasculature and tissues • Qualitative analysis can be performed on body tissues