Pathology 1 Flashcards
What are the two types of autopsy?
Hospital (<10%) Medico-legal (>90%)
What deaths are referred to the coroner?
Presumed natural (cause of death unknown) Presumed iatrogenic (caused by medical examination or treatment) Presumed unnatural
Who can make referrals?
Doctors
Relatives
Police
Who performs autopsies?
Histopathologists and Forensic pathologists
What is an autopsy?
An autopsy is a surgical procedure that consists of a thorough examination of a corpse by dissection to determine the cause and manner of death or to evaluate any disease or injury that may be present for research or educational purposes
What is inflammation?
Is the local physiological response to tissue injury. Not in itself a disease, but is usually a manifestation of disease
Define acute inflammation
The initial and often transient series of tissue reactions to injury
Define chronic inflammation
The subsequent and often prolonged tissue reactions following the initial response
Name some causes of inflammation
Microbial infections, hypersensitivity reactions, physical + chemical agents and tissue necrosis
Briefly describe the steps of acute inflammation
1) Initial reaction of tissue to injury
2) Dilation of vessels
3) Vascular leakage of protein-rich fluid
4) Neutrophil polymorph is the characteristic cell recruited to the tissue
5) Outcome may be resolution, suppuration (e.g abscess) or progression to chronic inflammation
How does microbial infections cause inflammation?
Bacteria release specific exotoxins - chemicals synthesised by them that specifically initiates inflammation
How does hypersensitivity reactions cause inflammation?
This reaction occurs when an altered state of immunological responsiveness causes an inappropriate/excessive immune reaction that damages the tissues
How does physical agents cause inflammation?
Either through physical trauma, UV, burns or excessive cooling
How does chemical agents cause inflammation?
Corrosive chemicals provoke inflammation through gross tissue damage
How does tissue necrosis cause inflammation?
Death of tissues from lack of o2 or nutrients resulting from inadequate blood flow is a potent inflammatory stimulus
Name 4 essential macroscopic appearances of acute inflammation
Rubor (redness)
Calor (heat)
Tumor (swelling)
Dolor (pain)
Rubor
Due to dilation of small blood vessels within the damaged area
Calor
Systemic fever which results from some of the chemical mediators of inflamation
Tumor
Results from oedema and due to inflammatory cells migrating into the area
Dolor
Results partly from stretching and distortion of tissues due to inflammatory oedema. Some chemical mediators e.g bradykinin are known to induce pain
Formation of the cellular exudate
The accumulation of neutrophil polymorphs within the extracellular space is the diagnostic histological feature of acute inflammation
What do endogenous chemical mediators cause?
Vasodilation, emigration of neutrophils, chemotaxis, increased vascular permeability, itching and pain
Causes of increased vascular permeability
Immediate transient chemical mediators and immediate sustained direct vascular injury
4 outcomes of acute inflammation
Resolution
Suppuration
Organisation
Progression to chronic inflammation
Causes of chronic inflammation
Primary chronic inflammation
Transplant rejection
Progression from acute inflammation
Recurrent episodes of acute inflammation
Macroscopic appearances of chronic inflammation
Chronic ulcer
Chronic abscess cavity
Granulomatous inflammation
Fibrosis
Microscopic appearances of chronic inflammation
Cellular infiltrate consists of lymphocytes, plasma cells and macrophages.
Neutrophil polymorphs are scarce.
Tissue necrosis may be a prominent feature, especially in granulomatous conditions.
Some of the macrophages may form multi-nucleate giant cells
Role of B-lymphocytes in chronic inflammation
On contact with antigen, become progressively transformed into plasma cells, which are cells specially adapted for the production of antibodies
Role of T-lymphocytes in chronic inflammation
Responsible for cell mediated immunity. On contact with antigen, T lymphocytes produce a range of soluble factors called cytokines. They recruit and activate other cell types
Granuloma
Aggregate of Epithelioid histiocytes, may contain lymphocytes and histiocytic giant cells
Cells that regenerate
Hepatocytes Pneumocytes All blood cells Gut epithelium Skin epithelium Osteocytes
Cells that don’t regenerate
Myocardial cells
Neurones
