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CHAPTER 3: THANATOLOGY

Death, Signs of Death & Postmortem Interventions

WBUHS Exam-Oriented Detailed Answers

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LONG & SHORT ANSWER QUESTIONS (5 & 4 Marks)

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Q1. Define Sudden Death. Enumerate causes of sudden death. Enumerate immediate, early and late changes after death. Write a note on postmortem biochemistry helping in estimation of time since death.

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DEFINITION OF SUDDEN DEATH

• Some authors restrict sudden death to deaths occurring instantaneously or within 1 hour of onset of symptoms.
• Emphasis is placed on the unexpected character rather than the suddenness.
• Incidence: approximately 10% of all deaths.
• Natural death = death caused entirely by disease; trauma or poison played no part.

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CAUSES OF SUDDEN DEATH (System-wise)

NOTE: Majority of sudden deaths from CAD are NOT associated with coronary thrombus or acute MI. Hypertension causing concentric LV hypertrophy can cause sudden death even without CAD.

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CHANGES AFTER DEATH

A. IMMEDIATE CHANGES (Signs of Death - "Not Alive" Signs)

1. Cessation of respiration - No chest movements, no air entry on auscultation
2. Cessation of cardiac activity - No heart sounds, no pulse, flat ECG (asystole)
3. Loss of consciousness - No response to stimuli
4. Pallor of skin - Fading of normal skin color
5. Insensibility to stimuli - No response to pain or reflexes
6. Loss of muscle tone - Primary flaccidity
7. Relaxation of sphincters - Involuntary voiding of urine and feces

B. EARLY POSTMORTEM CHANGES

C. LATE POSTMORTEM CHANGES

1. Putrefaction (Decomposition): Green discoloration of abdomen (iliac fossa first); marbling; formation of putrefactive gases; bloating; skin slippage; "green man" appearance. Due to bacterial action (mainly Clostridium welchii). Begins 24-48 hours.
2. Adipocere formation: Conversion of body fat into a grayish-white, waxy, soapy material (saponification of fats into fatty acids + hydrogenation). Requires warm, moist, anaerobic conditions. Takes 3-12 months. Of medico-legal importance as it preserves the shape of the body.
3. Mummification: Desiccation and shriveling of body in hot, dry, airy conditions. Requires low humidity and good ventilation. Takes weeks to months.
4. Maceration: Softening and disintegration of the body in water or fluid-filled cavities (especially in stillborn fetuses). Results in reddish discoloration and loosening of skin.
5. Skeletonization: Final stage - only bones remain.

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POSTMORTEM BIOCHEMISTRY - TIME SINCE DEATH

• Protected from external contamination
• Chemically stable even in decomposed bodies
• Not affected by putrefaction as readily as blood
• "Vitreous humour chemistry is uniquely stable and highly useful for estimating the post-mortem interval" (IPGME&R & SSKM Hospital question)

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Q2 & Q3. Define Rigor Mortis. Mechanism of Formation. How will you estimate time since death? Differentiate Rigor Mortis from Cadaveric Spasm. Factors affecting onset, persistence and disappearance.

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DEFINITION OF RIGOR MORTIS

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MECHANISM OF FORMATION OF RIGOR MORTIS

1. In life, muscle contraction requires ATP (adenosine triphosphate). Actin and myosin filaments interdigitate with each other during contraction due to ATP.
2. In the relaxed state: Actin filaments interdigitate with myosin only to a small extent.
3. After death, ATP is resynthesized briefly (for a short time) using available glycogen stores through anaerobic glycolysis (glycogenolysis).
4. Once glycogen is depleted, ATP cannot be resynthesized.
5. Without ATP, actin and myosin filaments fuse into a dehydrated stiff gel - this is RIGOR MORTIS.
6. Simultaneously, lactic acid accumulates (from anaerobic glycolysis), shifting muscle pH from slightly alkaline to distinctly acidic.
7. Rigor persists until autolysis of myosin and actin occurs as part of putrefaction - then secondary relaxation (secondary flaccidity) sets in.

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SEQUENCE OF RIGOR MORTIS

• Involuntary muscles: Heart within 1 hour (left chambers more affected due to thickness)
• Voluntary muscles sequence:
  • Eyelids: 3-4 hours
  • Face (masseters/jaw): 4-5 hours
  • Neck and trunk: 5-7 hours
  • Upper extremities: 7-9 hours
  • Legs: 9-11 hours
  • Small muscles of fingers and toes: 11-12 hours

• Commences in: 2-3 hours
• Complete (head to foot): 12 hours
• Persists for: 12 hours
• Passes off in: 12 hours
• Total duration: approximately 36 hours

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FACTORS AFFECTING RIGOR MORTIS

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MEDICOLEGAL IMPORTANCE OF RIGOR MORTIS

1. Confirms death (sign of death)
2. Helps estimate time since death (PMI)
3. Indicates position of body at time of death - if rigor is fixed in an unusual posture, position may have been changed after death
4. Helps distinguish rigor mortis from cadaveric spasm (the latter being of higher medicolegal value)
5. Helps detect postmortem translocation of the body

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DIFFERENTIATION: RIGOR MORTIS vs CADAVERIC SPASM

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CONDITIONS SIMULATING RIGOR MORTIS (Other than Cadaveric Spasm)

1. Freezing / Cold Stiffening: Tissues frozen solid at freezing temperatures; disappears on thawing; body then develops rapid but brief rigor. Occurs in Himalayan regions, Kashmir, North Bihar, UP, and cold chambers at 4°C.
2. Heat Coagulation / Heat Stiffening: Occurs in bodies exposed to >70°C (burns, high-voltage electrocution, falling into hot liquid). Heat coagulates muscle proteins causing stiffening + pugilistic (boxer) attitude (semi-flexed arms, semi-flexed legs, clenched fists). Normal rigor does NOT develop. Stiffening persists until coagulated albumin liquefies in decomposition.
3. Putrefaction stiffening: Accumulation of putrefactive gases in tissues causes false rigidity - limbs can be held up without support.

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Q4. Declare a Person Dead - Procedure. Modes and Manner of Death. Brain Stem Death. Medico-legal Duty.

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PROCEDURE TO DECLARE A PERSON DEAD

1. Absence of pulse (carotid, radial, femoral) for at least 5 minutes
2. Absence of heart sounds on auscultation for 5 minutes
3. Absence of respiration (no chest movement, no air entry) for 5 minutes
4. Fixed, dilated pupils non-reactive to light
5. Absence of corneal reflex
6. Pallor and coldness of body
7. Absent responses to painful stimuli

• ECG: Asystole for sustained period
• EEG: Isoelectric (flat) line
• Absent cerebral blood flow on Doppler / angiography

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MODES OF DEATH (Bichat's Classification)

1. Coma (death starting in the Brain): e.g., head injury, cerebral hemorrhage
2. Syncope (death starting in the Heart): e.g., cardiac arrest, coronary thrombosis
3. Asphyxia (death starting in the Lungs/Respiratory system): e.g., drowning, hanging, strangulation

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MANNER OF DEATH

1. Natural - caused entirely by disease
2. Accidental - unintentional injury or event
3. Suicidal - self-inflicted
4. Homicidal - caused by another person
5. Undetermined - insufficient evidence to classify

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BRAIN STEM DEATH

1. Brain stem houses respiratory and circulatory centers - vital for life
2. All sensory and motor pathways pass through brain stem
3. Medullary neurons are most resistant to anoxia; if they are dead, all higher centers are also dead
4. Brain controls and integrates the whole body - it is the "master of the orchestra"

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MINNESOTA CRITERIA (1971) for Brain Stem Death

1. Known but irreparable intracranial lesion
2. No spontaneous movements
3. Apnea when tested for 4 minutes (in absence of hypocarbia)
4. Absence of brainstem reflexes:
   • Dilated and fixed pupils
   • Absent corneal reflexes
   • Absent Doll's head (oculocephalic) phenomenon
   • Absent ciliospinal reflexes
   • Absent gag reflex
   • Absent vestibular response to caloric stimulation
   • Absent tonic neck reflex
5. EEG not mandatory
6. Spinal reflexes not important for diagnosis
7. All findings unchanged for at least 12 hours

Brain stem death is pronounced ONLY when the pathological processes responsible are deemed irreparable with available means.

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WHO CAN DECLARE BRAIN DEATH IN INDIA

1. Registered Medical Practitioner in charge of the hospital
2. Independent Registered Medical Practitioner (not connected to transplant)
3. Neurologist or Neurosurgeon
4. Medical Officer treating the patient

• None of these should be members of the transplant team
• Two sets of tests at an interval of 6 hours are required

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MEDICOLEGAL IMPORTANCE OF BRAIN DEATH

1. Allows legal withdrawal of life support - saving resources
2. Enables organ donation for transplantation (kidneys, heart, liver, corneas)
3. Settles insurance claims and inheritance
4. Relevant in criminal cases - if victim was on life support and support withdrawn
5. Prevents futile treatment

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MEDICO-LEGAL DUTY OF AN ON-DUTY MEDICAL OFFICER

1. Examine and certify death properly with clinical criteria
2. Inform the police if cause of death is unnatural/unknown (Section 174 CrPC / BNSS)
3. Issue cause of death certificate (MCCD) if death is natural and known
4. If unknown cause, refer for medico-legal autopsy
5. Do NOT alter or disturb the body or remove clothes until police arrive
6. Preserve all belongings and hand to police
7. Note time of death declaration
8. Cannot refuse treatment if patient arrives alive

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Q5. Define Brain Stem Death and its Medico-legal Importance. Mechanism and Typical Progression of Rigor Mortis. Exhumation - Definition and Procedure.

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EXHUMATION

• Homicide or suspected homicide disguised as suicide
• Suspicious poisoning
• Death from criminal abortion
• Criminal negligence

• Accidental death claim or insurance
• Workmen's compensation claims
• Professional negligence liability
• Survivorship and inheritance claims
• Disputed identity

• Written order from Executive or Judicial Magistrate [Section 196(4), BNSS / formerly Section 176 CrPC]

1. Obtain detailed information about the deceased and clothes worn at burial before starting.
2. Supervision: Conducted under supervision of a medical officer and Magistrate, with police officer present. Relatives may also be present [Section 196(5), BNSS].
3. Positive identification of the grave site using identifying features - location, headstone, grave marker; measure distance from permanent objects (trees, rocks, roads).
4. Conduct in natural light. If spectators present, screen the area with sheets or vehicles.
5. Uncover burial 10-15 cm at a time; note condition of soil, water content, vegetable growth.
6. Measure depth of grave from surface to skull and from surface to feet.
7. Open the burial pit to 30 cm on all sides of the body. Expose body with a soft brush.
8. After removing dirt, photograph the body in situ.
9. Record details of coffin/wrapping if present.
10. Postmortem examination (autopsy) is performed at the site of exhumation.
11. After examination, the body is re-interred (re-buried) at the same site.
12. Collect soil samples from above, below, and beside the body for toxicological examination (important for poisoning cases).

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Q6. Persistent Vegetative State (PVS). Difference between PVS and Permanent VS. Minnesota Criteria. Medicolegal Importance of Brain Death.

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PERSISTENT VEGETATIVE STATE (PVS)

• Patient appears "awake" but is not "aware"
• Reflexes and vegetative functions are preserved
• Can breathe spontaneously (unlike brain death)

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Q7. Short Notes (Short note questions from the chapter)

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RIGOR MORTIS PASSES OFF EARLY IN SEPTICAEMIC DEATHS

• Septicemia causes rapid depletion of glycogen stores in muscles (due to fever and catabolic state)
• Less glycogen = less ATP production = earlier onset of rigor
• Septicemia leads to early putrefaction - bacterial action digests muscle proteins (autolysis), breaking down actin-myosin cross-links faster
• The flaccidity of septicaemic limbs (due to toxic myopathy) also contributes to early loss of rigor

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CADAVERIC SPASM - MEDICOLEGAL IMPORTANCE

1. Indicates sudden and violent death associated with extreme emotional tension
2. Indicates physical activity of the muscles at the time of death
3. Weapon/object in hand proves antemortem activity - e.g.:
   • Knife firmly grasped in hand in suicidal cut throat (proves suicide not homicide)
   • Grass or weeds in hand in drowning (proves the person was alive when they entered water)
   • Hair grasped in homicidal scuffle (proves a struggle)
4. Cannot be simulated postmortem - no one can place a weapon in the hand of a corpse with the grip produced by cadaveric spasm
5. It is a vital phenomenon (antemortem origin) - provides proof of antemortem activity
6. Helps determine the nature of death (suicide vs. homicide vs. accidental)

"Cadaveric spasm has greater medicolegal importance than rigor mortis" - Raiganj "Cadaveric spasm is considered a sign of antemortem activity" - ESIC Joka

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NEGATIVE AUTOPSY

• Rate: 5-8% of all autopsies
• Even world's best centers have >5% negative autopsy rate

1. Inadequate history - deaths from vagal inhibition, epilepsy, laryngeal spasm, electrocution in water, anaphylaxis may not show external findings
2. Inadequate external examination - electrical burn marks (especially exit wounds) and needle pricks missed
3. Improper internal examination - faulty/incomplete organ examination
4. Insufficient histological examination - microscopic lesions (e.g., Aschoff bodies in rheumatic carditis, toxic myocarditis of diphtheria, small coronary thrombi) missed
5. Inadequate pathologist training - sudden deaths with CAD without thrombosis or infarction often missed by hospital pathologists

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ALGOR MORTIS CURVE IS SIGMOID-SHAPED

• In life, body temperature maintained at ~37°C by metabolic activity.
• After death, metabolic activity stops and body cools toward environmental temperature.
• Cooling occurs by conduction, convection, and radiation.

• Phase 1 (Plateau / Isothermic phase): For the first 0.5-1 hour after death, temperature does NOT fall (or falls very slowly) - due to residual metabolic activity (glycogenolysis) of dying tissues and intestinal bacteria
• Phase 2 (Rapid cooling phase): Temperature falls 1-1.5°C per hour (approximately; faster in thin, exposed, windy conditions)
• Phase 3 (Equilibrium phase): Body temperature approaches environmental temperature; rate slows

• Body weight (larger body cools slower)
• Clothing/covering (insulation slows cooling)
• Environmental temperature and air movement
• Body surface area to mass ratio
• Wet vs. dry body (wet cools faster)
• Posture of body

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VITREOUS HUMOUR IN TIME SINCE DEATH

• Protected anatomical location - posterior chamber of eye is isolated from systemic circulation
• Resistant to putrefaction (decomposition doesn't affect it rapidly)
• Not affected by antemortem disease states as much as blood
• Can be sampled even in decomposed bodies
• "Uniquely stable" - gives reliable biochemical data even after weeks of death

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CRITERION FOR DECLARING BRAIN STEM DEATH IN INDIA

1. Patient is on mechanical ventilation (apnoeic)
2. Known irreversible structural brain damage (diagnosed by clinical or imaging evidence)
3. Exclusion of reversible causes: hypothermia (core temp <35°C), drug intoxication, neuromuscular blocking agents, metabolic/endocrine disturbances

1. Absence of pupillary light reflex (pupils fixed and dilated)
2. Absent corneal reflex (bilateral)
3. Absent oculo-vestibular reflex (no eye movement to caloric stimulation with 50 ml ice cold water in each ear - 1 min apart - both sides)
4. Absent oculo-cephalic reflex (Doll's head - absent in brain death)
5. Absent motor response in cranial nerve distribution to somatic stimuli
6. Absent gag reflex and cough reflex to suction
7. Apnea test: Patient is pre-oxygenated; ventilator disconnected; PaCO2 allowed to rise to >60 mmHg; NO spontaneous breathing = confirms brain death

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ROLE OF CHIMERISM IN ORGAN TRANSPLANTATION

• In organ transplantation, donor cells can migrate from the graft to the recipient's body (microchimerism)
• This creates a state of immunological tolerance between donor and host
• Chimerism is thought to be one of the mechanisms of long-term graft acceptance without rejection
• Particularly important in bone marrow transplantation (macrochimerism)
• Detection by HLA typing, DNA fingerprinting, and cytogenetics

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SUSPENDED ANIMATION

• Drug overdose (barbiturates, opioids, alcohol)
• Hypothermia
• Drowning (particularly cold water drowning)
• Catalepsy (rare neurological condition)
• Trance states

• Person could be declared dead prematurely and buried alive
• Could lead to wrongful death certification
• All deaths should be confirmed by clinical and, if available, biochemical/electrical methods before certification

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Q9. Uses of MCCD (Medical Certificate of Cause of Death)

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MEDICAL CERTIFICATE OF CAUSE OF DEATH (MCCD)

• Part I: Direct cause of death (Ia - immediate cause, Ib - intermediate cause, Ic - underlying cause)
• Part II: Other significant conditions contributing to death but not related to cause in Part I

1. Legal proof of death - required for burial/cremation permits
2. Evidence in court proceedings (insurance, inheritance, criminal cases)
3. Needed for issuance of death certificate by registrar
4. Required for settlement of insurance claims
5. Helps determine manner of death legally
6. Required for succession and property transfer

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Q11. Negative Autopsy vs. Obscure Autopsy. Molecular Autopsy.

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NEGATIVE AUTOPSY vs OBSCURE AUTOPSY

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MOLECULAR AUTOPSY

• Sudden unexplained death in young (<40 years)
• Negative autopsy with suspected channelopathy or cardiomyopathy
• Family history of sudden cardiac death

• Next Generation Sequencing (NGS)
• Targeted gene panels (LQTS genes, CPVT genes, HCM genes)
• Whole exome sequencing

• Long QT syndrome (KCNQ1, KCNH2, SCN5A mutations)
• Brugada syndrome (SCN5A)
• Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) (RYR2)
• Hypertrophic Cardiomyopathy (HCM) (MYH7, MYBPC3)
• Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

• Likely cause: Hypertrophic Cardiomyopathy (HCM) or Commotio cordis (sudden blow causing ventricular fibrillation)
• Blunt trauma to chest can trigger ventricular fibrillation via autonomic/mechanical mechanism
• HCM: Asymmetric septal hypertrophy -> LV outflow obstruction -> myocardial ischemia -> fatal arrhythmia on exertion

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Q12. Objectives of Conducting an Autopsy. Time Since Death from Naked Eye Changes.

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OBJECTIVES OF MEDICOLEGAL AUTOPSY

1. Establish identity of the deceased
2. Determine exact cause of death (immediate, contributing, underlying)
3. Determine mode of death (coma, syncope, asphyxia)
4. Determine manner of death (natural, homicidal, suicidal, accidental)
5. Estimate time since death (PMI)
6. Establish the nature and timing of injuries - antemortem vs. postmortem
7. Collect evidence (trace evidence, bullets, fibres, foreign material)
8. Preserve viscera for chemical/toxicological analysis
9. Determine whether stillborn or live born (in neonatal deaths)
10. Exonerate or implicate individuals suspected of crime
11. Provide medico-legal opinion in court
12. Benefit public health - identify new/unreported disease patterns

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TIME SINCE DEATH FROM NAKED EYE (MACROSCOPIC) CHANGES

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SHORT NOTES (4-5 Marks Each)

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Livor Mortis (Postmortem Hypostasis)

1. Sign of death
2. Helps estimate PMI (time since death)
3. Color indicates cause of death
4. Position at time of death - lividity on anterior surface = prone; posterior = supine
5. Body was moved postmortem if lividity found on non-dependent parts (double lividity)
6. Helps detect postmortem translocation

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IMPORTANT EXAM MNEMONICS (WBUHS)

• A L R = Algor, Livor, Rigor (in approximate chronological order of clinical significance)

• E F N T U L = Eyelids, Face, Neck, Trunk, Upper limbs, Legs (cephalo-caudal)

• I-M-A-B-E-S = Irreparable lesion, Motor absent, Apnea (4 min), Brainstem reflexes absent, EEG not mandatory, Spinal reflexes not important, (unchanged for 12 hours)

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SUMMARY TABLE FOR QUICK REVISION

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