Calcification | Anatomy2Medicine
Degenerative Calcification

Calcification

 

  • Dystrophic calcification
  • When the deposition occurs locally in dying tissues(MCQ)
  • it occurs despite normal serum levels of calcium and in the absence of derangements in calcium metabolism.
  • metastatic calcification
      • the deposition of calcium salts in otherwise normal tissues (MCQ)
  • it almost always results from hypercalcemia secondary to some disturbance in calcium metabolism.
    • Dystrophic calcification
      • encountered in areas of necrosis
      • Calcification present in the  (MCQ)
        • atheromas of advanced atherosclerosis
        • aging or damaged heart valves, further hampering their function
        • Whatever the site of deposition, the calcium salts appear macroscopically as fine, white granules or clumps, often felt as gritty deposits.
        • Sometimes a tuberculous lymph node is virtually converted to stone (MCQ)
      • Histologically, with the usual hematoxylin and eosin stain, calcium salts have a basophilic, amorphous granular, sometimes clumped appearance. (MCQ)
      • They can be intracellular, extracellular, or in both locations.
      • In the course of time, heterotopic bone may be formed in the focus of calcification.
      • psammoma bodies
        • progressive acquisition of outer layers may create lamellated configurations(MCQ)
        • resembles grains of sand. (MCQ)
        • Some types of papillary cancers (e.g., thyroid) are apt to develop psammoma bodies. (MCQ)
      • In asbestosis, calcium and iron salts gather about long slender spicules of asbestos in the lung, creating exotic, beaded dumbbell forms (MCQ)
    • Metastatic calcification
      • occur in normal tissues whenever there is hypercalcemia.
      • four principal causes of hypercalcemia:
        • hyperparathyroidism
          • due to parathyroid tumors
          • ectopic secretion of PTH-related protein by malignant tumors (MCQ)
        • destruction of bone tissue, secondary to (MCQ)
          • primary tumors of bone marrow (e.g., multiple myeloma, leukemia)
          • diffuse skeletal metastasis (e.g., breast cancer)
          • accelerated bone turnover (e.g., Paget disease),
          • immobilization
        • vitamin D–related disorders (MCQ)
  • vitamin D intoxication
          • sarcoidosis (in which macrophages activate a vitamin D precursor(MCQ)
          • idiopathic hypercalcemia of infancy (Williams syndrome) (MCQ)
        • renal failure
  • causes retention of phosphate, leading to secondary hyperparathyroidism(MCQ)
    • Less common causes include
      • aluminum intoxication
      • occurs in patients on
        • chronic renal dialysis, (MCQ)
        • milk-alkali syndrome(MCQ)
          • due to excessive ingestion of calcium and absorbable antacids such as milk or calcium carbonate.
    • Metastatic calcification principally affects interstitial tissues of the gastric mucosa, kidneys, lungs, systemic arteries, and pulmonary veins. (MCQ)
      • Though quite different in location, all of these tissues excrete acid and therefore have an internal alkaline compartment that predisposes them to metastatic calcification. I
    • Massive deposits in the kidney (nephrocalcinosis) may in time cause renal damage