Pathologic calcification

Pathologic calcification

Pathologic calcification

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Pathologic Calcification - Stone-Cold Facts

  • Dystrophic Calcification: Deposition in damaged or necrotic tissue despite normal serum Ca2+ levels.

    • Examples: Atherosclerosis, aging/damaged heart valves, caseous necrosis in TB.
  • Metastatic Calcification: Deposition in normal tissue due to hypercalcemia (↑ serum Ca2+).

    • Examples: Hyperparathyroidism, sarcoidosis, vitamin D toxicity. Affects kidneys, lungs, gastric mucosa.

⭐ Psammoma bodies are lamellated calcifications seen in Papillary thyroid carcinoma, Serous cystadenocarcinoma of ovary, Meningioma, and Mesothelioma (PSaMMoma).

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Dystrophic Calcification - Damage Deposits

  • Pathogenesis: Calcium deposition in damaged, dying, or necrotic tissue, occurring despite normal serum calcium and phosphate levels. It is a common indicator of previous cell injury.
  • Mechanism:
    • Initiation: Begins in the mitochondria of dying cells that accumulate calcium due to membrane damage and loss of calcium regulation.
    • Propagation: Phosphatases in vesicle membranes bind calcium, creating a nidus for further calcium phosphate crystal formation and deposition.
  • Morphology:
    • Grossly: Fine, white, gritty granules or clumps.
    • Microscopically: Basophilic, amorphous, granular clumps. Can form lamellated psammoma bodies.
  • Clinical Examples:
    • Atherosclerosis plaques
    • Aging or damaged heart valves
    • Caseous necrosis in tuberculosis

Pathogenesis of dystrophic calcification in aortic valve

Key Distinctor: Dystrophic calcification occurs with normal serum calcium levels, differentiating it from metastatic calcification, which is driven by hypercalcemia.

Metastatic Calcification - Systemic Stones

  • Pathogenesis: Deposition of calcium salts in previously normal tissue, driven by a systemic mineral imbalance.
  • Core Defect: Always secondary to hypercalcemia (↑ serum Ca²⁺). Normal serum calcium is 8.5-10.2 mg/dL.
  • Mechanism: ↑ serum Ca²⁺ leads to an elevated calcium-phosphate product, causing precipitation in tissues with alkaline environments.
  • Major Causes of Hypercalcemia:
    • Hyperparathyroidism: Primary (adenoma) or secondary (renal failure).
    • Bone Resorption: Malignancy (myeloma, PTHrP), Paget disease, immobilization.
    • Vitamin D Disorders: Intoxication, sarcoidosis (macrophage activation of Vit D).
  • Favored Tissues (lose acid → alkaline pH):
    • Kidneys (nephrocalcinosis)
    • Lungs (alveolar septa)
    • Stomach (gastric mucosa)

Metastatic calcification in lung, kidney, and stomach

⭐ In contrast to dystrophic calcification, which is often incidental, metastatic calcification can cause significant organ dysfunction, such as renal failure from extensive nephrocalcinosis.

High‑Yield Points - ⚡ Biggest Takeaways

  • Dystrophic calcification deposits in damaged or necrotic tissue with normal serum calcium.
  • Metastatic calcification deposits in normal, living tissue due to hypercalcemia.
  • Dystrophic sites include atherosclerotic plaques, aging heart valves, and caseous necrosis.
  • Metastatic sites include kidneys (nephrocalcinosis), lungs, and gastric mucosa.
  • Psammoma bodies are lamellated calcifications seen in papillary thyroid carcinoma, meningioma, and serous ovarian tumors.
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Practice Questions: Pathologic calcification

Test your understanding with these related questions

A 57-year-old man comes to the emergency department for the evaluation of worsening fatigue, urinary frequency, and constipation over the past 5 days. He was recently diagnosed with metastatic bladder cancer and is currently awaiting treatment. He has smoked 1 pack of cigarettes daily for 35 years. Physical examination shows dry mucous membranes and diffuse abdominal tenderness. An ECG shows a shortened QT interval. Which of the following sets of serum findings is most likely in this patient? $$$ Calcium %%% Phosphorus %%% Parathyroid hormone %%% 1,25-dihydroxyvitamin D $$$

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Flashcards: Pathologic calcification

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Are patients with dystrophic calcifications usually normocalcemic? _____

TAP TO REVEAL ANSWER

Are patients with dystrophic calcifications usually normocalcemic? _____

Yes

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