Retrogressive changes are degenerative changes in cells characterized by abnormal structural changes and decreased functions. Cell damage can be reversible or irreversible, with cell death occurring when injury exceeds the cell's repair ability through necrosis or apoptosis. Causes include physical, chemical, infectious, biological, nutritional or immunological factors such as heat/radiation damage or impaired nutrient supply lacking oxygen or glucose. Cellular degeneration patterns include water overload causing hydropic degeneration, metabolite overload involving excess fat, glycogen or protein accumulation, and storage loading overloading by non-degradable substances.

1. Retrogressive changes are degenerative changes in cells and tissues
characterized by abnormal structural changes and decreased
functions.
Cell damage can be reversible or irreversible.
Cell death occurs when the severity of the injury exceeds the cell’s
ability to repair itself. Cell death may occur by necrosis or apoptosis.
CAUSES:
physical, chemical, infectious, biological, nutritional or immunological
factors.
heat or radiation can damage a cell by coagulating their contents.
Impaired nutrient supply, such as lack of oxygen or glucose,
impaired production of adenosine triphosphate (ATP) may also cause
cell death.

2. • The patterns of cellular degeneration and infiltration
are grouped as follows;
• 1) Water overload - Hydropic degeneration (Acute
cellular swelling, Cloudy Swelling).
• 2) Metabolite overload - It involves excessive
accumulation of normal metabolic products, such as
fat, glycogen, or protein (hyaline or proteinaceous).
• 3) Storage loading - It involves overloading by non-
degradable products such as pigments, minerals, and
exogenous substances.

3. Metabolite overload
• FAT OVERLOAD
• Fatty change (Fatty degeneration, Fat phanerosis)
• Fatty infiltration (Steatosis)
•
• PROTEIN OVERLOAD
• Hyaline Change (Hyalinisation, Hyaline degeneration)
• Fibrinoid
• Amyloidosis
• Mucopolysaccharidosis (myxoid or myxomatous degeneration,
mucoid degeneration)
•
• CARBOHYDRATE OVERLOAD
• Glycogen degeneration

5. • Cloudy swelling is a degenerative change in cells, in which there is
an intra-cytoplasmic accumulation of water due to incapacity of
the cells to maintain the ionic and fluid homeostasis.
• Cell injury affects ionic transfer of the cell membrane. As a result
there is accumulation of water in the cell.
• The mitochondria swell giving the cytoplasm a cloudy or granular
appearance.
• Water also accumulates between cells, with resultant swelling of
tissues. Accumulation may be temporary or permanent and cause
cell injury.
• Cloudy swelling is also called albuminoid degeneration, hydropic
degeneration, or parenchymatous degeneration.
•

6. • CAUSES:
• Cloudy swelling may occur due to;
• A) bacterial toxins
• B) chemical toxins
C) cellular hypoxia
AFFECTED ORGANS: It may be local or diffuse,
affecting the whole organ.It is easy to be observed
in parenchymal organs;
•liver (hepatitis, hypoxia),
•kidney (shock),
•myocardium (hypoxia, phosphates intoxication).

7. EFFECTS:
Gross examination:
•The affected organ is enlarged, pale and soft.
•Blood capillaries are compressed that causes the pallor (an
unhealthy pale appearance).
•There is increased turgor and increase in weight of the organ.
Microscopic examination:
The cells are enlarged, with a clear cytoplasm.
There is swelling in the mitochondraia due to water
accumulation
There is presence of small clear or pale vacuoles. It may have
cloudy appearance; “cloudy swelling”.
In severe cases many variable sized vacuoles appear in the
cytoplasm. They represent pinched-off segments of
the endoplasmic reticulum. This This pattern of non-lethal
injury is called hydropic change or vacuolar degeneration or
“ballooning degeneration”.
ultrastructural changes of reversible cell injury include:
•Plasma membrane: There is Blebbing or Blunting of plasma
membrane.
•Distortion of microvilli
•Mitochondrial changes - decrease in aerobic respiration and
production ATP
•Dilation of the endoplasmic reticulum