05-PATHOLOGIC CALCIFICATION ggg 2008.ppt

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2. Define calcification
Types of calcification
Causes, feature and effect of dystrophic
calcification
Causes, feature and effect of metastatic
calcification

3. is a common process in a wide variety
of disease states
 it implies the abnormal deposition of
calcium salts with smaller amounts of
iron, magnesium, and other minerals.

4. Dystrophic calcification:
When the deposition occurs in dead or dying
tissues
it occurs with normal serum levels of calcium

Metastatic calcification:
The deposition of calcium salts in normal
tissues
It almost always reflects some derangement
in calcium metabolism (hypercalcemia)

6. Dystrophic calcification is encountered
in areas of necrosis of any type.
It is certain in the atheromas of
advanced atherosclerosis, associated
with intimal injury in the aorta and
large arteries

7. Although dystrophic calcification may be an
incidental finding indicating insignificant past
cell injury, it may also be a cause of organ
dysfunction.
For example,
Dystrophic calcification of the aortic valves is an
important cause of aortic stenosis in the elderly

8. Dystrophic calcification of the aortic valves

9. calcium salts are grossly seen as fine white
granules or clumps, often felt as gritty deposits.
Sometimes a tuberculous lymph node is
essentially converted to radio-opaque stone.
Histologically, calcification appears as
intracellular and/or extracellular basophilic
deposits.
In time, heterotopic bone may be formed in the
focus of calcification.

10. Dystrophic calcification in the wall of the
stomach

11. Initiation (or nucleation)
Propagation (intracellular or
extracellular)
The ultimate end product is the
formation of crystalline calcium
phosphate

12. Initiation in extracellular sites occurs in
membrane-bound vesicles about 200 nm in diameter
in degenerating cells.
Phosphates accumulate as a result of the action of
membrane-bound phosphatases
Initiation of intracellular calcification occurs in
the mitochondria of dead or dying cells that have lost
their ability to regulate intracellular calcium.

13. After initiation in either location,
propagation of crystal formation
occurs.
This is dependent on:
1.the concentration of Ca2+ and PO4- in the
extracellular spaces
2.the presence of mineral inhibitors
3.the degree of collagenization, which
enhances the rate of crystal growth

15. Metastatic calcification can occur in
normal tissues whenever there is
hypercalcemia.

16. 1.increased secretion of parathyroid hormone
2.destruction of bone due to the effects of
accelerated turnover (e.g., Paget disease),
immobilization, or tumors (multiple
myeloma, leukemia, or diffuse skeletal
metastases)
3.vitamin D-related disorders including vitamin
D intoxication and sarcoidosis
4.renal failure, in which phosphate retention
leads to secondary hyperparathyroidism.

17. Metastatic calcification can occur widely
throughout the body but principally affects
the interstitial tissues of the vasculature,
kidneys, lungs, and gastric mucosa.
The calcium deposits morphologically
resemble those described in dystrophic
calcification.

18. Extensive calcifications in the lungs may
produce remarkable radiographs and
respiratory deficits

Massive deposits in the kidney
(nephrocalcinosis) can cause renal
damage.

19. 

21. Depositions of lipids:
Fatty change: accumulation of free
triglycerides in cells, resulting from
excessive intake or defective transport
(often because of defects in synthesis of
transport proteins); manifestation of
reversible cell injury

22. Cholesterol deposition: result of
defective catabolism and excessive
intake; in macrophages and smooth
muscle cells of vessel walls in
atherosclerosis

23. Deposition of proteins: reabsorbed
proteins in kidney tubules;
immunoglobulins in plasma cells
Deposition of glycogen: in
macrophages of patients with defects
in lysosomal enzymes that break down
glycogen (glycogen storage diseases)

24. Deposition of pigments: typically
indigestible pigments, such as
carbon,
lipofuscin (breakdown product of lipid
peroxidation),
iron (usually due to overload, as in
hemosiderosis)

25. Dystrophic calcification: deposition of
calcium at sites of cell injury and
necrosis
Metastatic calcification: deposition of
calcium in normal tissues, caused by
hypercalcemia (usually a consequence
of parathyroid hormone excess)