Clinical Pathology Flashcards
Reasons for conducting an autopsy
- Allows very thorough examination of the deceased, the extent of their disease, their treatment and its effects
- Audit - Major discrepancies between stated cause of death and actual cause of death, main diagnosis missed in 15% of cases.
- Monitoring effectiveness of new treatments
- Teaching
- Research - Creutzfeldt-Jakob Disease (CJD) research relies heavily on post-mortem brain tissue examination.
Differences in consent between a hospital autopsy and a coroner’s autopsy
Hospital autopsy
- Consent must be obtained from next of kin
- With consent, any material may be taken
Coroner’s autopsy
- No consent of next of kin necessary but their wishes should be observed
- Material can only be taken if it bears upon the cause of death
Cases that must be reported to the Coroner
- CoD unknown
- Suicide
- Poisoning
- Neglect by self/others
- Shortly after/in police custody
- CoD is violent, unnatural or suspicious
- CoD may be related to employment/industrial disease
- Person has not been seen by identifying doctor in last 14 days
- Death may be an accident
- Abortion
- Occurred during an operation or before recovery from effects of anaesthetic
Natural causes of unexpected death
- Cardiovascular disease; Coronary artery disease, cardiomyopathy, myocarditis, floppy mitral valve.
- Vascular system; Ruptured aortic aneurysm.
- Central nervous system; subarachnoid haemorrhage, caused by berry aneurysm, epilepsy, intracerebral haemorrhage.
- Respiratory system; pulmonary embolus, asthma.
- GI tract; Pancreatitis, bleeding oesophageal varices.
- Drugs/alcohol; often go together.
- Trauma; self-induced or caused by others.
Types of injury
Bruise Abrasion Laceration Cut Stab
Bruise definition and cause
An extraverted collection of blood which has leaked from damaged small arteries, venues, and veins but NOT capillaries.
Caused by blunt force trauma e.g. punch.
Abrasion definition and cause
Graze or scratch limited to epidermis.
Caused by tangential force e.g. friction burn, whip, stamp.
Laceration definition and cause
Blunt force trauma to overstretched skin, where skin can be compressed against bone
Caused by blunt force trauma over area where skin is overstretched.
Deep and will bleed, margins ragged with crushing, bruising, bridging fibres arch across the skin defect.
Cut and stab differences, definitions, and causes
Cut - Length longer than depth.
Stab - Depth greater than width.
Cause - Sharp object such as knife or broken beer bottle.
Edges clean and well demarcated, minimal damage to surrounding tissue.
Definition of neoplasm
New growth
“Abnormal mass of tissue, the growth of which is virtually autonomous and exceeds that of normal tissues. The growth is uncoordinated and persists after the cessation of the stimuli that initiated the change.”
Definition of cancer
Pathological condition characterised by the proliferation of neoplastic cells that tend to invade surrounding tissue and metastasise too new body sites.
Definition of tumour
A mass caused by a neoplasm.
Definition of metastasis
The development of secondary malignant growths at a distance from a primary site of cancer.
Definition of carcinogen
Agents that cause genetic damage and induce neoplastic transformation of cells.
Distinguishing features of benign tumours
- Well differentiated
- Slow growing
- Grow as cohesive, expansile, encapsulated masses that remain localised to their site of origin
- Seldom metastasize.
Distinguishing features of malignant tumours
- Show various levels of differentiation, well/moderate/poor
- Rapid growth, chemotargets
- Poorly demarcated (fixed), infiltrate and destroy the surrounding tissue
- With 2 exceptions (gliomas, basal cell carcinomas), all metastasize, approx 30% patients present with metastasis.
Pathological features assessed for prognosis in staging
Staging
- T - Primary Tumour size
- N - Nodal status
- P - Presence of metastases
Pathological features assessed for prognosis in grading
Grading
- Histological
- Low and high grade (less useful than grading)
- Based on degree of differentiation and the number of mitoses.
Types of carcinogens
Chemicals Radiation Microbial agents Hormones Miscellaneous
Examples of chemical carcinogens
- Aromatic amines activated in liver, cause bladder cancer
- Aromatic hydrocarbons, cause skin and lung cancer
Examples of radiation-related carcinogens
- Ultraviolet radiation, causes skin cancer
- Ionising EM radiation, causing leukaemia.
Examples of microbial agents that are carcinogenic
- Epstein-Barr virus, causes Burkitt’s lymphoma
- Human papilloma virus, causes cervical cancers
- Hepatitis B/C viruses, hepatic(liver) cancers
- HHV8 Kaposi’s sarcoma-associated herpesvirus, causes sarcoma
- Helicobacter pylori (bacterium), causes stomach/pancreatic cancer
Aim of screening
To detect cancer either at preinvasive stage or early enough for successful treatment
Requirements of successful screening programs
- Reliable prediction of tumour behaviour
- Treatment readily available
- Target population has enough people at risk to justify expense
- Cost-effective and reliable screening tool
