NotesWala
✏️
FMT - Second Year BHMS

GENERAL TOXICOLOGY

General Toxicology - Introduction

Definition and Importance of Toxicology

Toxicology is the study of the adverse effects of chemicals, including their mechanism of action, dose-response relationships, and potential harm to humans and the environment. It is a crucial field in medicine, environmental science, and public health, as it helps to identify and mitigate the risks associated with exposure to toxic substances.

Classification of Poisons

Poisons are substances that cause harm or death when ingested, inhaled, or come into contact with the body. They can be classified into various types based on their properties, effects, and sources.

Types of Poisons

  • Natural Poisons: These are substances found in nature that can cause harm or death. Examples include:
    • Plant toxins (e.g., Deadly nightshade, Castor bean)
    • Animal toxins (e.g., Snake venom, Scorpion venom)
    • Fungal toxins (e.g., Mushroom poisoning)
  • Synthetic Poisons: These are man-made substances that can cause harm or death. Examples include:
    • Pharmaceuticals (e.g., Opioids, Benzodiazepines)
    • Industrial chemicals (e.g., Pesticides, Herbicides)
    • Explosives
  • Biological Poisons: These are living organisms or substances that can cause harm or death. Examples include:
    • Bacteria (e.g., Botulism, Anthrax)
    • Viruses (e.g., HIV, Smallpox)
    • Fungi (e.g., Molds, Yeast)
  • Chemical Poisons: These are inorganic substances that can cause harm or death. Examples include:
    • Heavy metals (e.g., Arsenic, Mercury)
    • Inorganic acids (e.g., Hydrochloric acid, Sulfuric acid)
    • Inorganic bases (e.g., Sodium hydroxide, Ammonia)

Forensic Significance of Poisons

  • Detection of Poisons: Poisons can be detected in the body using various analytical techniques, such as chromatography and spectroscopy.
  • Toxicology Reports: Toxicology reports can provide information on the type and amount of poison present in the body.
  • Medicolegal Investigation: Medicolegal investigation can help determine the cause and manner of death in cases of poisoning.

Legal Provisions

  • Poison Act: The Poison Act regulates the sale and use of poisons in various countries.
  • Toxic Substances Control Act: The Toxic Substances Control Act regulates the use of toxic substances in various industries.
  • Environmental Protection Act: The Environmental Protection Act regulates the use and disposal of toxic substances in the environment.

Duty of a Doctor

  • Reporting of Poisoning: Doctors are required to report cases of poisoning to the authorities.
  • Treatment of Poisoning: Doctors are responsible for providing treatment for poisoning cases.
  • Medicolegal Investigation: Doctors may be required to participate in medicolegal investigation of poisoning cases.

Forensic Procedure for Poisoning

→ Collection of Samples: Samples are collected from the body and environment. → Analytical Techniques: Analytical techniques are used to detect and quantify the poison. → Toxicology Reports: Toxicology reports are prepared based on the analytical results. → Medicolegal Investigation: Medicolegal investigation is conducted to determine the cause and manner of death. → Report and Documentation: A report is prepared and documented based on the findings.

Management of Poisoning

Poisoning refers to the condition where a person is exposed to a substance that can cause harm or death. The management of poisoning involves identifying the substance, assessing the severity of poisoning, and providing treatment to prevent or mitigate harm.

Symptoms of Poisoning

  1. Initial Symptoms: Headache, dizziness, nausea, vomiting, and abdominal pain.
  2. Systemic Symptoms: Cardiovascular, respiratory, neurological, and gastrointestinal symptoms.

Types of Antidotes

  1. Specific Antidotes: Designed to counteract the effect of a specific poison.
  2. General Antidotes: Can counteract the effect of multiple poisons.

Specific Antidotes

  1. Naloxone: Used to reverse opioid overdose.
  2. Flumazenil: Used to reverse benzodiazepine overdose.
  3. Atropine: Used to reverse organophosphate poisoning.
  4. Digoxin-specific antibody: Used to reverse digoxin poisoning.

General Antidotes

  1. Activated Charcoal: Used to adsorb and remove poison from the gastrointestinal tract.
  2. Gastric Lavage: Used to remove poison from the stomach.
  3. Emetics: Used to induce vomiting to remove poison from the stomach.
  4. Supportive Care: Used to manage symptoms and prevent complications.

Management of Poisoning

  1. Assess the Patient: Evaluate the patient's symptoms, medical history, and exposure to the poison.
  2. Identify the Poison: Determine the type and amount of poison ingested or inhaled.
  3. Provide Supportive Care: Manage symptoms and prevent complications.
  4. Administer Antidotes: Use specific or general antidotes as necessary.
  5. Monitor and Follow-up: Monitor the patient's condition and provide follow-up care as necessary.

Poison Information

  1. Poison Control Center: A 24-hour hotline that provides information and advice on managing poisoning.
  2. Toxicology Reports: Laboratory tests that analyze the patient's blood, urine, or tissue samples for the presence of poisons.

Diagnosis of poisoning in living and dead subjects

Poisoning in Living Subjects

  • Poisoning in living subjects is diagnosed based on the clinical features and symptoms presented by the patient.
  • A thorough history of the events leading to the poisoning, including the type and amount of substance ingested, is crucial for diagnosis.
  • Physical examination, laboratory tests, and imaging studies may be used to confirm the diagnosis.
  • Clinical features such as vomiting, diarrhea, abdominal pain, and respiratory distress may indicate poisoning.

Diagnosis of Poisoning in Dead Subjects

  • In dead subjects, the diagnosis of poisoning is based on postmortem examination and toxicological analysis of blood, tissue, and other bodily fluids.
  • The postmortem examination involves a thorough external and internal examination of the body to identify any signs of poisoning.
  • Toxicological analysis of biological samples may involve various methods such as chromatography, mass spectrometry, and immunoassay.
  • The presence of substances such as heavy metals, pesticides, and illicit drugs may indicate poisoning.

Duties of a Medical Practitioner in a Suspected Case of Poisoning

  • The medical practitioner must first establish the identity of the patient and obtain a thorough history of the events leading to the poisoning.
  • The patient must be stabilized and treated for any acute symptoms.
  • Laboratory tests and imaging studies may be ordered to confirm the diagnosis.
  • The medical practitioner must also notify the authorities and report the case to the relevant toxicology laboratory.
  • The patient's family and friends must be informed of the situation and provided with counseling and support.
  • The medical practitioner must also maintain a record of the case and provide a detailed report to the relevant authorities.

Forensic Analysis

  • Forensic analysis involves the examination of physical evidence and biological samples to determine the cause and extent of poisoning.
  • The analysis may involve various techniques such as toxicological analysis, DNA analysis, and histopathological examination.
  • The results of the forensic analysis may be used to determine the identity of the substance and the extent of its effects on the body.
  • The findings of the forensic analysis may also be used to determine the cause and manner of death.

Legal Aspects

  • The medical practitioner must report any suspected case of poisoning to the relevant authorities.
  • The medical practitioner must also provide a detailed report of the case to the relevant authorities.
  • The medical practitioner may be called as a witness in a court of law to provide evidence in a case related to poisoning.
  • The medical practitioner must maintain confidentiality and adhere to the relevant laws and regulations governing the handling of patient information and evidence.