Secondary Hyperparathyroidism

• excessive PTH secreted by parathyroid glads in response to hypocalcemia.
• Seen in chronic renal failure (most common cause of secondary HPT)
• Bone and joint pain are common
• Parathyroid hypertrophy
• no role for parathyroid surgery
• Vitamin D deficiency can cause secondary HPT

Normal calcium level with elevated PTH

Normal calcium blood levels with an elevated PTH might be due to vitamin D levels.  Low vitamin D levels lead to elevated PTH levels to help maintain normal calcium blood levels.

Chronic Renal Failure

• Failing kidneys fail to convert enough vitamin D to its active form
• Does not adequately excrete phosphate into the urine
• Insoluble calcium phosphate forms in the body which removes calcium from the circulation – thus hypocalcemia and thus increases parathyroid hormone in an attempt to increase serum calcium levels

Other causes besides renal failure

• Malabsorption dependent bariatric surgery
• malabsorption due to chronic pancreatitis, small bowel disease

What is tertiary hyperparathyroidism?

Tertiary hyperparathyroidism occurs when the correction of the underlying cause will not stop excess PTH secretion

Vitamin D and Calcium?

The body needs vitamin D to absorb calcium from our diet.

What is primary hyperparathyroidism?

• Increased PTH secretion and raised serum calcium levels
• 85% caused by parathyroid adenoma (usually only one gland affected)
• 10% caused by chief cell hyperplasia

What is hungry bone syndrome?

• Severe Hypocalcemia seen after surgical correction of HPT
• Chronically deprived bone aggressively absorbs calcium