Handout of Forensic Medicine 2024 PDF

Handout of forensic medicine 1 Medical Ethics The Duties of Clinical Care members (Bioethical Principles): A. Respect Autonomy (free decision): This means respecting the patient to make his autonomous choice. The patient must indicate his approval and willingness to accept prop...

Handout of forensic medicine 1 Medical Ethics The Duties of Clinical Care members (Bioethical Principles): A. Respect Autonomy (free decision): This means respecting the patient to make his autonomous choice. The patient must indicate his approval and willingness to accept proposed treatment. It also requires decision-making capacity: Capacity: Is the ability of an individual to weigh up information, compare and choose. Competency: Is a legal term means the ability of the person to perform a legally recognized act The respect for the patient autonomy and dignity leads to two further rights – informed consent and confidentiality. B. Protect life and health: Clinicians should practice medicine to high standard actions intended to benefit the patient or others C. Fairness &Justice: This is concerning about fairness in the distribution of medical services. D. Compassion: Is the understanding and concern for another person’s distress, it is essential for the practice of medicine. Doctor’s Responsibilities: 1) Duty to patient. 2) Duty to public at large (community). 3) Duty towards law enforcers. 4) Duty towards his profession 5) Duty to his colleagues and other health profession. 1) Duty to The Patient: The physician owes the duty of: Care to a patient using skill, and knowledge in a perfect manner to achieve the best benefit to the patient. Disclose all information to the patient Treating the patient with compassion and respect. Supporting the dignity of all persons and respect their uniqueness. Treating all patients equally and fairly, especially in scarce resources. Fidelity, honesty and lack of self-interest to his patient Telling the truth to the patient and must act all times in the best interest of the patient. Physician - Patient Relationship: The patient-physician relationship entails special obligations for the physician to serve the patient's interest because of the specialized knowledge that physician's hold and the imbalance of power between physicians and patients. 2  Initiating and Discontinuing the Patient-Physician Relationship In the absence of a pre-existing relationship, the physician is not ethically obliged to provide care to an individual person unless no other physician is available, as in the case of isolated communities or when emergency treatment is required. Under these circumstances, the physician is morally bound to provide care and, if necessary, to arrange for proper follow-up. Physicians may also be bound by contract to provide care to beneficiaries of participating health plans. Abandonment: It is defined as the improper unilateral termination of the relationship. Confidentiality (professional secrecy): Confidentiality shows a respect for an individual's autonomy and their right to control the information relating to their own health. Breaking or breaching Confidentiality: In some cases, the doctor may, at their own discretion, decide to disclose information about his patients. 1. Upon the patient's request: 2. In case of expert witness: 3. For the sake of the patients: 4. For the sake of the community: 5. For the sake of the doctor: 6. Past criminal and violent behavior that has resulted, Consent and Informed Consent: Consent is defined as: Deliberate and voluntary assent or agreement to some act or purpose, implying physical and mental power and free action. Types of consent: a) Implied consent b) Expressed consent c) Informed consent Elements of valid informed consent 1. Consent by a competent adult. 2. Consent by parent /legal guardians 3. With free will (voluntariness), 4. Comprehension of the given information. 5. The patient acknowledgment of understanding and consent before the intervention/treatment proceeds. Consent is considered invalid in the following situations: 1. If the act consented to is illegal 2. Consent given by one who had no legal authority to give 3. Consent induced by misrepresentation or fraud 4. Consent given by legally incompetent person. 2) Duty to Public: Medical help when natural disaster 3  Medical help during train accidents. Compulsory notification of births, deaths, infectious diseases, food poisoning etc. Help victims of house collapse, road accidents, fire etc Duty to attend emergency and give first aid at least. Report to the competent medical authority any suspicion of an epidemic. 3) Duty towards law enforcers (Police): Inform police in all cases of: 1. Injury, illegal abortions, suicide, homicide. 2. Poisoning 3. Burns. 4. Battered child cases. 4) Duty to his profession: The physician should: a) Maintain the honor of the profession through taking care for his personal conduct and appearance. b) Adopt lifelong learning. c) Refrain from any act or conduct that would infringe his honesty and integrity when dealing with a patient. 5) Duty to other physicians: He should acquire sufficient degree of respect to his colleagues, should not diminish their capabilities. Replacing another colleague in the treatment of a patient. He should treat his colleagues or their relatives without fees except for needed investigations. Ethical and legal issues in medicine 1. Assisted reproduction 2. Gender correction procedure 3. Organ transplantation 4. Terminal incurable diseases and dying patients Medical Certificates A physician can, and should not refrain to, give his patient a certificate regarding his condition of his own use but not on request of people other than the patient himself (wife or husband). Medical Malpractice Definition of Malpractice: is a legal suite against physician as a result of failure to follow the accepted standards of practice of his profession, resulting in harm to the patient. Medical malpractice can result in serious personal injury and/or wrongful death,. Signing a physician's consent form does not mean you consent to substandard medical attention. 4  Professional Misconduct: At all times a medical practitioner is expected to comport himself with a high sense of decorum in public and private matters. Guides for Professional Conduct Advertising Association Addiction Adultery Medicolegal Aspects of Death Death: Is defined as the cessation of physical life in a living organism. Clinical death or Somatic death: Is defined as complete and irreversible cessation of all body functions including circulation, respiration and brain function Brain Death: It is defined as a complete and irreversible cessation of brain activity or function, including brain stem. Evidence of irreversibility is required. Molecular Death: It is defined as "the death of individual organs and tissues of the body consequent upon the cessation of circulation". Molecular life: It is the period between somatic & cellular death. Although life ceases in the body, it persists in its components such as the tissues & cells that respond to physical, chemical or thermal stimuli. MLI of molecular life: Organ Transplantation could be carried out only during the period of molecular life. The liver should be taken within 15 min. after death, the kidney within 45 min., the heart within 60 min and cornea up to 6 hours. Suspended Animation: (Apparent death): It is a condition in which signs of life are not found as the vital functions are temporarily interrupted or reduced to minimum. However, life continues, and resuscitation is successful in such cases. It may occur under certain specialized conditions for example drowning or hypothermia. Persistent Vegetative State (PVS): It is a condition of patients with severe brain damage in whom coma has progressed to a state of wakefulness without detectable awareness. It is also known as cortical death. Criteria of PVS 5  1. Patients often open their eyes. 2. They may experience sleep-wake cycles or be in a state of chronic wakefulness. 3. They are unresponsive to external stimuli, except, possibly, pain stimuli. 4. They may exhibit some behaviors that can be construed as arising from partial consciousness, such as grinding their teeth, swallowing, smiling, shedding tears, grunting, moaning, or screaming without any apparent external stimulus. Diagnosis of death: 1. Cessation of respiration 2. Cessation of circulation 3. Unresponsiveness 4. Primary flaccidity 5. Contact flattening 6. Changes in the skin 7. Changes in the eyes: -Opacity of the cornea ((2hours after death). -Flaccidity of the eyeball (↓ IOP, starts 30 min after death). -Dilated pupil. -Retinal vessels show fragmentation of the blood column (starts 15 min after death). -Tache noire: brownish discoloration of exposed sclera due to accumulation of cellular debris and dust. 8. Absence of cerebral and brain stem functions. Brain stem death The cerebrum is intact; however, the cerebral functions are cut off by the brain stem lesion. Criteria for diagnosis of brain death: o Absent light reflex. o Absent corneal and gag reflex. o Absent facial or tongue movement. o Absent cough reflex: A suction catheter is introduced into the endotracheal or tracheostomy tube to deliberately stimulate the carina. The patient is closely observed for any cough response or movement of the chest or diaphragm. o Absent brain stem functions: a. Absent vestibulo-ocular reflex b.Absent oculo- cephalic reflex (Doll’s eye phenomenon) c. Apnea Test Confirmatory Tests o Flat EEG (at least 10 min). o No cerebral circulation present on angiographic examination. 6  o Nuclear brain scanning: Brain death confirmed by absence of uptake of isotope in brain parenchyma and/or vasculature, (hollow skull phenomenon). Precautions in Diagnosis of Brain Death: 1) Nature of coma must be known: Known structural disease or irreversible systemic metabolic cause that can explain the clinical picture. 2) Some causes must be ruled out: Body temperature must be above 32° C to rule out hypothermia. No chance of drug intoxication or neuromuscular blockade. Patient is not in shock. 3) There should be no change in any of the above tests i.e. vestibulo-ocular, oculo-cephalic, and apnea test, when repeated after 24hrs. Sudden Unexpected Natural Death This is unexpected death of apparently healthy individual, or death within 24 hours of a terminal disease. Sudden death may occur as a result of: 1.Trauma: Head injury, burns, electric shock. 2.Poisoning: CO, insecticide, narcotics or hypnotics. 3.Disease (Natural death): When a rapid termination of life develops in clinically silent patient (e.g. hypertension, atherosclerosis, brain abscess aneurysm). Causes of sudden death: Cardiovascular causes: Respiratory causes: Central nervous causes: Postmortem Changes Medicolegal significance of postmortem changes: 1. An estimation of the time since death can be made by observing the extent by knowing the rate at which that change has progressed. 2. Some of the changes which occur after death can be mistaken by the inexperienced for injuries sustained before death. 3. The decomposition process may alter or obliterate true antemortem injuries, making determination of the cause of death difficult. Primary flaccidity Is defined as the complete relaxation and loss of both tone & reflexes of voluntary and involuntary muscles immediately after death and remains till the onset of postmortem rigidity. Contact flattening - Is the flattening of the convex parts of the muscles compressed against flat surface. - It is due to the effect of the body weight, loss of muscle tone, and loss of elasticity after death. Ocular changes 7  Reflexes Loss of corneal and light reflexes immediately after death. Sclera Shows “Taches Noire” which is brownish black discoloration that occurs due to accumulation of cellular debris & dust on the sclera when the eyes remain opened for few hours (3–4 hours).44 Cornea Loss of the clear glistening appearance & the cornea becomes dry, cloudy and opaque (2 hours). Pupils The pupils usually assume a midsized dilate position, which is the relaxed neutral position of the papillary muscle. With the development of rigor mortis the pupils become constricted & lastly they become dilated again with the development of 2ry flaccidity. Intra-ocular pressure (IOP) The eyeball feels progressively softer within minutes due to drop of IOP. The normal intra-ocular pressure is (10 – 20 mm Hg), this pressure drops to its half at the time of death & becomes nil by 2 hours after death. Fundus - Pallor of the optic disc. - Segmentation of retinal vessels that occurs within 15 min of death (one of the earliest positive signs). Skin Changes - After death, the skin becomes pale. - The skin loses its elasticity leading to absence of P.M. gaping of wounds. - It loses its translucency due to absence of circulation (the webs of the fingers are opaque to transillumination). Postmortem Cooling Rate of cooling: Heat loss occurs only on the body surface and the core heat (visceral temperature) from the interior can reach the body surface only by conduction so the fall of internal body temperature is delayed for about 45 minutes till the establishment of a temperature gradient towards the surface and may thus remain unchanged for some time (1-2 hours after death). Thereafter, body temperature drops approximately 1.5 degrees per hour. In any case, body temperature will usually approximate that of the environment within 12-18 hours. Factors Affecting Postmortem Temperature Decline: Normal body core temperature is 37.2°C. Delayed Rate of cooling: 8 1. Conditions which increase body temperature include: intense physical activity, drugs (e.g. cocaine), and fever due to natural illness, heat stroke, some infections, and pontine hemorrhage. 2. Increased humidity. 3. Increased environmental temperature. 4. Insulation: This means clothing, body wrappings, or even body fat. Accelerated rate of cooling: 1. Low body temperature prior to death e.g. hypothermia, congestive cardiac failure, massive hemorrhage, and shock. 2. Dry environment. 3. Ventilation: A well-ventilated environment will speed the rate of cooling; this would increase evaporation as well as increase heat loss through convection. 4. Low Environmental temperature: The colder the environment, the more rapid the cooling. A cadaver cools more rapidly in water than in air because water is a far better conductor of heat. Hypostasis (Livor Mortis) or Postmortem Lividity Definition: Lividity is a dark purple discoloration of the skin. Cause: It is due to the gravitational pooling of blood in the veins and capillary beds of the dependent parts of the body following cessation of the circulation. Onset: The process begins immediately after the circulation stops, becomes visible 1hr, pronounced within 3 hrs as mottled patches and completed in 8hrs after death. Medicolegal Importance of Lividity 1.Estimation of time of death from its extent: o Visible 1 hour after death as dull red patches which deepen in intensity and coalesce. o It becomes well developed within 3 hours as mottled patches. o Is maximally developed and fixed at 8 hours following death. o The blanching of postmortem lividity by thumb pressure indicates that the lividity is not fully fixed. 2.It may denote the cause of death: a-From Its color: 9  o Red-pink color. In case of deaths from exposure to cold, cyanide and carbon monoxide intoxication o Brown color due to methemoglobinemia (usually associated with overuse of certain drugs e.g. nitrites, nitrates phenacetin). o Typical purple lividity in case of refrigeration of a body. o Deep blue: in asphyxial death. b-From its extent and distribution: o ill-defined in severe hemorrhage. o Marked in case of asphyxia. 2. It may denotes repositioning the body, e.g. if the body moved from the prone to the supine position within the first six hours after death, this will result in a dual pattern of lividity, since the primary distribution will not fade completely. Rigor Mortis Definition: Rigor mortis is a gradual stiffening of the body's musculature which occurs after death. It does not involve any significant shortening of the muscle fibers. It is not a permanent change; under usual conditions, rigor mortis disappears by 48 hours after death. - Mechanism: It results from chemical changes involving muscle proteins (actin and myosin). Normally, ATP inhibits the fusion of actin and myosin. Rigor mortis occurs because metabolism continues in muscles for a short while after death. (ATP) is produced from the metabolism of a sugar compound called glycogen. ATP is a principal energy source for muscular activity. As the store of glycogen is exhausted, ATP can no longer be made and its concentration decreases, leading to the formation of abnormal links between actin and myosin. The abnormality produces the stiffening of the muscle, which persists until the links are decomposed. Medicolegal importance of rigor mortis: 1.Sure sign of death 2.Estimation of time of death by the distribution and degree of rigor. In an average person at ordinary room temperature, rigor usually becomes apparent 2 hours after death. It is usually completed 12 hours after death. It begins to go away 18 hours after death, and usually disappears 24-48 hours after death 3.Denotes that the body was moved after death (how? if rigor is developed in a body, but the position of the body is not consistent with the scene, then one can conclude that the body was moved after death). Factors affecting rigor mortis: 1- Effect of temperature: In cold weather, rigor is delayed in onset and offset while in hot climate it is rapid in onset and of short duration 10  2- Muscle bulk & age: Rigor is more rapid in onset & offset and of short duration in less developed body musculature 3- Muscle activities before death (cause of death): Convulsions and exertion before death e.g. in electrocution, strychnine, tetanus, exercise or violence are usually followed by rapid onset and offset of rigor mortis (depleted ATP). Conditions Simulating Rigor (D.D.): 1. Cadaveric Spasm (instantaneous rigor): This is a rare form of muscular stiffening which occurs at the time of death (Instantaneous). It usually affects groups of muscles in the arms. It is due to extreme nervous tension. MLI of cadaveric spasm: It records the last act of life (e.g. tight clutching of a knife). It is an antemortem phenomenon. i.e. the person was alive. It cannot be reproduced after death by placing a weapon in the hands. 2. Heat stiffening: It is due to coagulation of the muscle proteins. This process is seen in fire deaths and involves actual cooking of the muscle fibers. Because the fibers shorten, one sees a typical "pugilistic" appearance. Heat stiffening obscures rigor mortis. 3. Cold stiffening: Fat and muscle become solid at low temperatures. As temperature rises, tissues become soft again then rigor mortis occurs. Secondary Flaccidity With the development of 2ry flaccidity, the muscles become soft and flaccid once again, but do not respond to mechanical and electrical stimuli. This stage is synchronous with the onset of putrefaction. Putrefaction It is the process of decomposition of soft tissues resulting in resolution of the body from organic to inorganic state. Mechanism: 1. Autolysis: Certain enzymes are released from the tissue cells after death causing liquefaction of the body tissues. 2. Bacterial action: Bacteria frequently found in the tissues and normally present in the respiratory or intestinal tracts commonly aerobic bacteria. Medico-legal importance of putrefaction: 1- It is a sure sign of death. 2- It can be used for estimation of the PMI. 11  After 1 day in summer or 2 days in winter, (color changes): - The first external sign is greenish discoloration of the right iliac region over the caecum (fluid faeces, full of bacteria and the caecum lies superficial). - Arborization (marbling) of blood vessels on the root of the neck, over the shoulder and on the groin. This occurs due to the distension of veins by putrefactive gases and bluish to green discoloration by altered blood (sulph- Hb). After 2 days in summer: Bloating of the face and trunk occur. After 3 days in summer or 1 week in winter (mainly gas formation): - Spread of green discoloration and arborization over the whole body. - Distension of the abdomen and genitals. - Formation of gas filled skin blisters. - Swelling of the face with protrusion of the tongue & eyeballs. - Coarse, foul smell, bloody froth comes from the mouth & nostrils. - Blurring of features and discoloration make identification very difficult even by near relatives. After 1 week in summer or 2 weeks in winter: - Peeling of the epidermis with falling of hair & nails. - Bursting of the abdomen and the viscera are liquefied to a dark doughy mass. - Eggs of flies laid at body orifices will hatch into larvae. After 6 months: - All soft tissues are liquefied and percolate to the surroundings and to the ground. - Bones attached by ligaments are left (avascular structures). After 1 year: Separate bones become lighter, whiter less smelly & more brittle. Factors Affecting Development of Postmortem Decomposition: a- Medium in which the body is buried or found e.g. the body is in the open, in water, or buried. Bodies in air will decompose more quickly, and buried bodies more slowly (rule of thumb: 1 week in air = 2 weeks in water = 8 weeks in ground) given the same environmental temperature. b- Environmental temperature and humidity: Optimal temperature 20-40oC ( >50 oC &