Hyperparathyroidism and hypercalcaemia

Question 1

What is the definition of hyperparathyroidism? [3]

Answer 1

overactive parathyroid glands / secrete excess parathyroid hormone / causes levels of Ca2+ in the blood to increase leading to hypercalcaemia

Question 2

What is the definition of hypercalcaemia? [2]

Answer 2

high Ca2+ level in the blood serum / greater than 2.6mmol/L

Question 3

What are the causes of primary hyperparathyroidism? [3]

Answer 3

1. ~80% due to solitary adenoma
2. ~20% due to hyperplasia of all glands
3. <0.5% due to parathyroid cancer

Question 4

What is the pathophysiology and lab results of primary hyperparathyroidism? [5]

Answer 4

1. results in excess PTH production due to adenoma/hyperplasia
2. increased Ca2+
3. increased PTH (inappropriate secretion)
4. decreased PO4(3)-
5. increased alkaline phosphatase (ALP)

Question 5

What is the pathophysiology and lab results of secondary hyperparathyroidism? [5]

Answer 5

1. physiological compensatory hypertrophy of all parathyroid glands resulting in excess PTH secretion due to hypocalcaemia
2. seen in chronic kidney disease / vitamin D deficiency
3. decreased Ca2+
4. increased PTH (appropriate secretion)
5. increased PO4(3)-

Question 6

What is the pathophysiology and lab results of tertiary hyperparathyroidism? [6]

Answer 6

1. after prolonged secondary hyperparathyroidism causing glands to act autonomously having undergone hyperplastic or adenomatous change
2. results in excess PTH secretion that is unlimited by feedback control
3. due to chronic kidney disease
4. increased Ca2+
5. increased PTH (inappropriate secretion)
6. increased PO4(3)-

Question 7

What is the pathophysiology and lab results of malignant hyperparathyroidism? [3]

Answer 7

1. parathyroid-related protein (PTHrP) produced by some squamous cell lung cancers, breast and renal cell carcinomas
2. mimics the action of PTH resulting in hypercalcaemia so increased Ca2+
3. decreased PTH as PTHrP not detected in the assay

Question 8

What are the other causes of hyperparathyroidism? [2]

Answer 8

1. excessive Ca2+ intake

2. drugs - thiazide diuretics / vitamin D analogues / lithium

Question 9

What are the signs of hyperparathyroidism/hypercalcaemia? [4]

Answer 9

1. bones - pain, fracture, osteopenia/osteoporosis
2. stones - renal stones
3. groans - abdominal pain, constipation, vomiting, polyuria, polydipsia, weight loss, cardiac arrest
4. moans - depression, tiredness, weakness, confusion, coma

Question 10

What is the diagnosis of primary hyperparathyroidism? [3]

Answer 10

1. increased PTH (inappropriate secretion)
2. increased Ca2+
3. decreased PO4(3)-

Question 11

What is the diagnosis of secondary hyperparathyroidism? [3]

Answer 11

1. increased PTH (appropriate secretion]
2. decreased Ca2+
3. increased PO4(3)-

Question 12

What is the diagnosis of tertiary hyperparathyroidism? [3]

Answer 12

1. increased PTH (inappropriate secretion]
2. increased Ca2+
3. increased PO4(3)-

Question 13

What is the diagnosis of malignant hyperparathyroidism? [3]

Answer 13

1. decreased PTH (appropriate)
2. increased Ca2+
3. variable PO4(3)-

Question 14

What is the treatment for primary hyperparathyroidism? [3]

Answer 14

1. excision of adenoma / all 4 hyperplastic glands
2. complications - hypoparathyroidism and recurrent laryngeal nerve damage (hoarseness)
3. oral cinacalcet - increased sensitivity of parathyroid cells to Ca2+ so decreased PTH secretion

Question 15

What is the treatment for secondary and tertiary hyperparathyroidism ? [2]

Answer 15

1. treat the cause e.g. chronic kidney disease

2. excision of parathyroid glands

Question 16

What is the treatment for malignant hyperparathyroidism? [1]

Answer 16

chemotherapy may help

Question 17

What are some other general treatments/advice? [3]

Answer 17

1. increased fluid intake or rehydrate with IV 0.9% saline fluids to prevent stones
2. avoid thiazides
3. avoid high Ca2+ and vitamin D intake