Hyperparathyroidism

Disease class: Parathyroid diseases 

Physiology

• Parathyroid hormone (PTH) is a hormone produced by the parathyroid glands.
  

Pathophysiology

• Hyperparathyroidism is a pathological state caused by blood PTH levels higher than the reference range.
• This leads to excessive osteoclast activity.
• There is excessive bone resorption, which may produce osteomalacia. 
• Calcium is released from the bone as the calcified matrix is resorbed. Serum calcium will rise (unless calcium is also being lost), which may produce hypercalcaemia.

 

Causes

Primary hyperparathyroidism

• This term describes an elevated, inappropriate level of PTH.
• It occurs as a consequence of excessive PTH production. 
• Potential causes include: a benign proliferation of chief cells, parathyroid adenoma.

Secondary hyperparathyroidism

• This term describes an elevated, but appropriate level of PTH. The glands hypertrophy to produce more PTH. 
• This occurs as a physiological response to hypocalcaemia. 
• Potential causes include kidney diseases.

Tertiary hyperparathyroidism 

• This term describes a state of excessive PTH production.
• This is a potential consequence of prolonged secondary hyperparathyroidism and glandular hypertrophy.

 

See also

• Hypoparathyroidism
• Pseudohypoparathyroidism