Ageing and Degeneration Flashcards
Name 4 features associated with ageing
- Decline in tissue cellularity
- Reduced blood flow due to vascular disease
- Tissue atrophy
- Tissue replacement by an acellular collagenous matrix
What is the histopathological mechanism of HYALINE degeneration?
Replacement of normal cells with an acellular, amorphous, eosinophilic material
What is the histopathological mechanism of ELASTOIC degeneration?
Defective fibroblast function leads to an altered elastic matrix and reduced elasticity
What is the histopathological mechanism of CALCIFICATION degeneration?
Calcium is deposited as hydroxyapetite crystals - can be metastatic in hypercalcaemic states or dystrophic in normocalcaemic states
What is the histopathological mechanism of AMYLOID degeneration?
INSOLUBLE protein deposited in tissue around blood vessels and basement membranes
What are the stains used to test for amyloid?
H&E stain (Haematoxylin and Eosin) - homogenous pink appearance
Congo red stain WITH Polarised light - Apple green birefringence appearance
Crystal Violet
Thioflavin T
H&E stain produces what appearance with amyloid?
Homogenous pink appearance
Congo Red stain produces what appearance with amyloid?
Apple green birefringence when examined with polarised light
What is the histopathological mechanism of HYDROPIC degeneration?
Reversible change - cells are enlarged containing cytoplasmic Vacoules
What is the histopathological mechanism of CLOUDY SWELLING degeneration?
Reversible change - Cells are enlarged and filled with granules or fluid, representing intracellular oedema
What is the histopathological mechanism of FATTY CHANGE degeneration?
Fat accumulates in cells for unknown reasons or after damage from different agents
What is the histopathological mechanism of GLYCOGEN INFILTRATION degeneration?
Glycogen infiltration into tissue causing structural changes
What are clinical examples of HYALINE degeneration?
Walls of arteriosclerotic small vessels of the eye in ageing, diabetes, HTN
What are clinical examples of ELASTOIC degeneration?
- Skin in ageing
- Pterygia
- Pseudoxanthoma elasticum - ruptures in Bruch’s membrane expose the choroid (angioid streaks)
What are clinical examples of CALCIFICATION degeneration?
- Band keratopathy: Calcification of Bowman’s layer and superficial stroma
–> can also occur in hyperparathyroidism, hypervitaminosis D, Sarcoidosis - Cataracta Ossea: Calcification in the fibrous and degenerative cortex of the lens
- Paget’s disease: associated with calcification of Bruch’s membrane
- Pthisis Bulbi - Ossification of metaplastic fibrous tissue derives from proliferation of the RPE in a hypotonic eye
- Woven and lamellar bone is located on the inner surface of Bruch’s membrane
- ossification can extend to the vitreous and choroid
What are clinical examples of AMYLOID degeneration? - Localised
- Solitary nodules in eyelid, conjunctiva, orbit
- In the cornea - seen as Lattice dystrophy, gelatinous drop-like dystrophy
- Amyloid from polypeptide hormones in endocrine tumours
- Amyloid from prealbumin leads to cerebral deposits in Alzheimer’s disease
What are clinical examples of AMYLOID degeneration? - Systemic
- Pseudoexfoliation syndrome:
-An amorphous, eosinophillic substance is deposited on the anterior lens capsule, ciliary processes, iris, TM leading to secondary glaucoma - Waldenstrom’s Macroglobulinaemia:
-Amyloid is light chain derived from Immunoglobulins
-RA/Familial mediteranean fever:
-Amyloid is derived from serum protein (an acute phase reactant)
What are clinical examples of HYDROPIC degeneration?
Infection
Intoxication
Anaemia
Circulatory disturbance
What are clinical examples of CLOUDY SWELLING degeneration?
Mild Infection
Intoxication
Anaemia
Circulatory disturbance
What are clinical examples of FATTY CHANGE degeneration?
- Arcus Senilis: Fatty infiltration of the peripheral stroma
- Xanthelasma: Lipid within clumps of macrophages in the dermis of the eyelid (with ageing/high cholesterol)
- Deposition of lipid and cholesterol in the intima of arteries - leading to atheroma/thrombosis
What are clinical examples of GLYCOGEN INFILTRATION degeneration?
- Diabetes Mellitus - Lacy vacuolation of iris pigment epithelium
- Long standing neural retinal detachment due to lack of nutrition and in proliferating RPE cells
Define Dystrophy
A primary Inherited disorder that can occur at any age
- They may involve a single matrix component
