Hyperparathyroidism

Question 1

Causes of hyperparathyroidism

Answer 1

Adenoma, primary hyperplasia (nodular or diffuse), parathyroid carcinoma

Question 2

Adenoma

Answer 2

Can either be familial primary hyperparathyroidism or a part of MEN, specifically MEN-1 and MEN-2a.
Most commonly occurs due to cyclin D1 gene inversion.
Can also be due to hypocalciuric hypercalcemia where a mutation leads to inactivation of Ca sensing receptors, leading to constitutive PTH release.

Question 3

Clinical aspects of hyperparathyroidism

Answer 3

Can lead to a clinically silent hypercalcemia, pain in bones and osteitis fibrosa cystica, renal stones, GI disturbances, neuromuscular abnormalities, polyuria and secondary polydipsia

Question 4

Diagnosis

Answer 4

Lab results:
Increased free serum Ca AND PTH. PTH can potentially be low it the Ca increase is due to malignancies (normal values: 2.2-2.5 mmol/L total and 1.1-1.4 mmol/L ionized). Hypophosphatemia (normally it is 0.81-1.45 mmol/L).
Increased excretion of both phosphate and calcium.

Question 5

Treatment

Answer 5

Parathyroidectomy

Question 6

Secondary causes of hyperparathyroidism

Answer 6

Any condition which causes chronic depression in the serum Calcium level. The most common disorder is renal failure: Decreased phosphate excretion gives increased serum phosphate. The phosphate directly binds calcium and thus lowers the amount of free calcium. The kidneys also provide 1-alpha hydroxylase which is necessary for synthesis of the active form of Vitamin D, thus leading to decreased intestinal uptake of calcium.

Question 7

Treatment of secondary hyperparathyroidism

Answer 7

Cure the primary disease if possible