Metastatic calcification

Pathological deposition of calcium salts in tissues

Metastatic calcification is a pathological condition characterized by the deposition of calcium salts in otherwise normal tissues, often as a result of elevated serum calcium levels. This condition is distinct from dystrophic calcification, where calcium deposits occur in damaged or necrotic tissues.

Pathophysiology

Metastatic calcification occurs when there is an imbalance in calcium and phosphate metabolism, leading to hypercalcemia. This can result from various underlying conditions such as hyperparathyroidism, chronic kidney disease, or sarcoidosis. The elevated calcium levels in the blood precipitate in tissues, particularly those with an alkaline environment, such as the lungs, kidneys, and gastric mucosa.

Common Sites of Calcification

Metastatic calcification can affect multiple organ systems, but it is most commonly observed in the following areas:

• Lungs: Calcium deposits can occur in the alveolar walls, leading to respiratory complications.
• Kidneys: Calcification in the renal parenchyma can impair kidney function and contribute to nephrocalcinosis.
• Gastric mucosa: The stomach lining can also be a site of calcium deposition, potentially affecting digestion.
• Blood vessels: Vascular calcification can lead to increased arterial stiffness and cardiovascular complications.

Cardiovascular calcification as seen in a histological section

Causes

Several conditions can lead to metastatic calcification, including:

• Hyperparathyroidism: Overactivity of the parathyroid glands increases calcium release from bones.
• Chronic kidney disease: Impaired renal function can lead to phosphate retention and secondary hyperparathyroidism.
• Vitamin D intoxication: Excessive vitamin D can increase intestinal absorption of calcium.
• Sarcoidosis: This granulomatous disease can cause increased production of calcitriol, leading to hypercalcemia.

Diagnosis

Diagnosis of metastatic calcification involves a combination of clinical evaluation, laboratory tests, and imaging studies. Elevated serum calcium and phosphate levels are indicative of the condition. Imaging techniques such as X-rays, CT scans, or MRI can reveal calcifications in affected tissues.

Treatment

The management of metastatic calcification focuses on treating the underlying cause of hypercalcemia. This may involve surgical intervention, such as parathyroidectomy in cases of hyperparathyroidism, or medical management with medications that lower calcium levels, such as bisphosphonates or calcimimetics.

Prognosis

The prognosis of metastatic calcification depends on the underlying cause and the extent of tissue involvement. Early detection and management of the underlying condition can improve outcomes and prevent complications.

Related pages

• Dystrophic calcification
• Hypercalcemia
• Nephrocalcinosis
• Vascular calcification