6. Learning From The Dead Flashcards
Forensic pathology
> The study of injuries and or diseases to determine the cause of death
- A post-mortem investigation of sudden or unexpected death or trauma to the living
- Speacilisit knowledge of injuries and diseases to determine cause of death
- Conduct autopsis
Role of forensic pathologist
- Confirm death has occurred
- Estimate time since death
- Ensure positive identification
- Record injuries and natural disease if any
- Determine the cause of death
- Form an opinion on possible manner of death through reconstruction of events
5 possible Manner of death
Natural • Accidental • Homicide • Suicide • undetermined
What is an autopsy
• Inspect body internally or externally
—> Autopsy (necropsy and post-mortem examinations are synonymous) means to ‘see for oneself’.
• It is an opportunity to directly inspect and analyse the organs.
2 types of autopsy
- The clinical or academic autopsy:
* The medico-legal or forensic autopsy:
• The clinical or academic autopsy:
○ The medical attendants, with the consent of relatives, seek to learn the extent of the disease for which they were treating the deceased patient.
○ Study disease and treatment given to patient
• The medico-legal or forensic autopsy:
○ Performed on the instructions of the legal authority responsible for the investigation of sudden, suspicious, unnatural or criminal deaths.
○ Legal requirement e.g. when attending can’t determine cause of death
○ Consent is not required for this
Physical evidence
—> Before an autopsy can occur, a medical examiner will search for any physical evidence on the body
- Weight
- Height
- Fingerprints
- Physical distinguishing charactersitics
- Physical evidence e.g. bite marks
- Biological evidence – insect or qounds
- Chemical evidence – alcohol or drugs
- Physioloigcal evidence – bone, hair, blood
Rigor mortis
—-> Stiffening of body because of lack of oxygen in muscle cells.
• Begins around 4 hours after death.
• Begins in eyelids and small muscles of jaw, then to neck and rest of body.
• Sits in more quickly when there has been a violent struggle (uses up energy in muscles)
• Completely sits in within 12 hours after death and lasts around 36 hours before body returns to non-rigid state
Impacted by temperature and environment
Rigor mortis - time period
Less than 3 hours – warm 3 - 6 hours – warm but stiff 6 hours – cool but stiff 36 hours – cold and no stiffness • Use to determine cause of death
Liver mortis
–> Discoloration of skin after death = blue to purple areas
• Caused by gravity-induced stagnation and settling of red blood cells in small blood vessels.
• Commonly referred to as “lividity
• Occurs 6-8 hours after death.
• Occurs in parts of body closest to ground by effect of gravity
Types of wounds
- Lacerations - irregular tearing of tissue that is contaminated wit bacteria
- Incised wounds – not deep but caused by sharp items
- Puncture wounds- sharp pointed object
- Abrasions - rubbing of skin
- Contusions – rupture of small vessels
- Gunshot wounds – determine type of firearms distance of shooter
Steps of an autopsy
Rigor mortis and liver mortis • Internal and external • Opening of trunk: • Y incision • Open rib cage • Remove organs • Specimens for testing – fixed with formaldehyde • Brain stored in 10% formaldehyde for 2 weeks • closing
Purpose of an autopsy
• find Difference between antimortem and post mortem body
Why examine dead bodies
To:
– Understand the anatomy of the body
– Correlate structure to function
– study the effects of disease processes and cause of death
Assess the effect of therapeutic interventions
• Find evidence for criminal proceedings
4 Common affected areas of sudden death
- Head ‘
- Heart
- Blood vessels
- Lungs
Head - sudden causes of death
Extradural haemorrhage
Subdural haemorrhage
Sub arachnoid haemorrhage
Intracerebral haemorrhage
Intracranial aneurysm
Meninges - structure and definition
Meninges – membranous covering of connective tissue that support brain and spinal cord • Made of 3 layers ○ Periosteal dura mater ○ Meningeal dura mater ○ Arachnoid mater
Extradural haemorrhage
– collection of blood between the skull out outer layer of the dura (periosteal dura).
○ Occurs due to head trauma and can lead to sudden death
Subdural heamorrhage
– collection of blood in the subdural space due to bleeding from vein in the area – connection of blood between arachnoid dura layer and meningeal dura mater
○ Occurs due to head trauma and can lead to sudden death
○ This can increase pressure on underlying brain tissue
Sub arachnoid haemmorhage
– collection of blood in sub arachnoid space
○ Associated with rupture of aneurysm due to dilation or weakness of blood vessel
○ Pressure and compression on brain tissue
○ Related to trauma, infection, neoplasma
Intracerebral haemoorhage
- haemorrhage within brain tissue
○ Space occupying tissue, causes compression and pressure on brain, affecting function
Intracranial aneurysm
– weakness in the wall
○ Trauma or hypertension leads to rupture and death
Stroke
—> clinical manifestation of blockage or disruption to brain tissue
2 types of stroke
Ischaemic
Haemorrhagic
Ischaemic stroke
• Thrombosis, embolism, narrowing, blocking lumen, reudced blood flow, blood flow infarction and ischaemic defects
Haemorrhagic stroke
• Aneurysm, blood spreads around brain tissue may damage cell and lead to stroke
Neuropathology
Cellular pathology to
– Central nervous system
– Peripheral nerves
– Muscle
Neuropathology - Relevant autopsies – determine if cause is
- Trauma
* Neurodegenerative disease
Alzhheimers disease
• Neurodegenerative disease
• Alzheimer patient has atrophy (decrease in structure size)
○ Cortical atrophy – common withg aging
Atrophic brain – gyri of brain are shrunken and suclcus are widened
Lewy body dementia
- Microscopic examiantion of tissue
- Associated with progressive diseases that affect mental abilities and hallucinates e.g. like parksinsons disease
Lewy bodies – basophilic material accumulated in brain tissue
2 neurodegenerative diseases
Alzhheimers disease
Lewy body dementia
Heart
Coronary artery thrombosis
Valvular disease
Cardiomyopathies
Coronary artery thrombosis
• Coronary artery thrombosis – thrombis in artery occluding all artery
Valvular disease
- Aortic valve stenosis
* Associate with degernative changes and aging, defects in abnormal valves due to calcification, thickness and fibrosis
Cardiomyopathy
—> group of disorders that are Non-ischaemic, non-inflammatory disease of heart muscle
2 types of cardiomyopathy
– Hypertrophic = thickened heart muscle in ventricle and intraventricle septum ,impact lumen size
– Dilated = dilation within ventricular lumen, weakened, increase lumen diameter
Both affect pumping of blood
Hypertrophy
- Left ventricular hypertrophy – increase in size of left ventricle affects lumen and pumping mechanism
- Right ventricular hypertrophy – reduce in lumen size, increase in thickness of muscle in heart wall
dilatation
• Dilated cardiomyopathy – no change in thickenes but there is dialtion, enlargement of ventricle which affects relaxing and filling mechanism of heart
Blood vessels
Ruptured abdominal aortic aneurysm
Ruptured abdominal aortic aneurysm
• Ruptured abdominal aortic aneurysm = weakness in wall due to atherosclerosis (underlying cause)
○ Causes dilation of the vessel and increases pressure = rupture and death
Lung
Pulmonary embolism
Bronchopneumonia
Viral pneumonia
Lung carcinoma
Metastatic tumour within the lung
Perionitis
Pulmonary embolism
presence of thrombi emboli (underlying cause can be cancer)
○ Causes obstruction of main vessel , large pulmonary artery = death
Bronchopneumonia
○ White b=patches around bronchi and bronchioles
○ Can lead to death
○ Grey to yellow dry elevated lesions
Viral pneumonia
○ Patchy areas of inflammation congestion, necrosis, fibrosis, hemorrhagic areas
○ Within the interstitium (tissue of the lung)
Lung carcinoma
depends on type of cancer and position of cancer in lung
○ Squamous cell carcinoma – occurs in periphery (A)
○ Adenocarcinoma = occurs in lobe of lung (B)
○ Asbestosis (C)
○ Different cancers change lung different in image
Metastatic tumour within the lung
○ Multiple nodules affecting lung, associated with metastasis – cancer in different part of body
○ Find out from which organ the metastasis has happened
Peritonitis
yellowsish disclouration in peritioneum
○ Happens in response to irritation of peritoneum and accumulation of pepinasoxidase ??
○ If extensive it can lead to death
Paediatric pathology
• Paediatric pathologists are trained in paediatric surgical pathology and autopsy.
• Paediatric autopsies – reasons for it
– Deaths in utero
– Death in infancy eg sudden infant death syndrome
– Suspicious deaths
Paediatric autopsies
Macroscopic examination • Microscopic examination • Toxicology • Microbiology – In utero infections – Sudden infant death • Genetic studies – Karyotyping
