Pathological Calcification Flashcards
What is pathological calcification
Abnormal deposits of calcium salts on tissues, small amounts of mg, fe, other minerals can also be present
Two types
Dystrophic calcification
Metastatic calcification
Characteristics of dystrophic calcification
Dying tissues
Normal Ca levels
No derangement In calcium metabolism
Characteristics of metastatic calcification
Normal tissues
Abnormal Ca levels
derangement In calcium metabolism
Pathogenesis of dystrophic calcification
Found in necrotic tissues regardless of the type
The denatured proteins in degenerate or necrotic tissue bind with phosphate ions and the phosphate ions reacts with calcium to form the precipitate of calcium phosphate
When membrane is damaged it causes accumulation of calcium and the calcium deposit is what attracts deposition of phosphates ions
A single necrotic cell can bind with calcium and then attract layers of mineral deposition and form what
Psammoma body
How do psammoma bodies appear macroscopically
Macroscopically they appear as fine white granules or clumps which are gritty to touch
How do psammoma bodies appear microscopically
Microscopically Ca salts look basophilic (purplish blue) armophous (without a clearly defined shape) and may be lamellated appearance
Examples of dystrophic calcification
1) in aging or damaged heart vessels
2) uterine leiomyomas
3) damaged blood vessels
4) Tumors e.g papillary thyroid carcinoma, papillary serous carcinoma
5) athlerosclerosis
6) tuberculous lymph nodes
7) Asbestosis in the lungs
8) lithopaedion
Characteristics of metastatic calcification
Occurs in tissues where there is hypercalcemia( increased blood calcium levels)
Derangement at any level may lead to increase in calcium levels
Where does metastatic calcification principally affect
Principally affects interstitial tissues of gastric mucosa, lungs, kidneys, pulmonary veins and systemic arteries
Aetiology of metastatic calcification
Hyperparathyroidism
Destruction of bone tissue
Vitamin D related disorders ( vitamin d intoxication, Sarcoidosis (macrophages activate vitamin d precursor) ,Williams syndrome (idiopathic hypercalcemia of infants causes abnormal sensitivity to vit D)
Hyperphosphatemia
Milk alkali syndrome (ca supplements taken for e.g osteoporosis together with antacids)
What is the final common pathway in dystrophic calcification
The final common pathway is the formation of calcium phosphate mineral as an apatite which is similar to the hydroxyapatite of bone
The cycle of calcium and phosphate deposition continues until what is formed
A microcrystal which then propagates and lead to more deposition of calcium
