Hyperparathyroidism

Question 1

What is primary hyperparathyroidism?

Answer 1

increased secretion of PTH unrelated to the plasma calcium concentration

Question 2

What is secondary hyperparathyroidism?

Answer 2

increased secretion of PTH secondary to hypocalcaemia

Question 3

What is tertiary hyperparathyroidism?

Answer 3

Autonomous PTH secretion following chronic secondary hyperparathyroidism

Question 4

List 4 causes of primary hyperparathyroidism

Answer 4

Parathyroid adenoma
Parathyroid hyperplasia
Parathyroid carcinoma
MEN syndrome

Question 5

List 2 causes of secondary hyperparathyroidism

Answer 5

Chronic renal failure

Vitamin D deficiency

Question 6

Describe the epidemiology of hyperparathyroidism

Answer 6

Primary: incidence of 5/100,000
F > M
Peak incidence: 40-60 yrs

Question 7

List 8 symptoms of hypercalcaemia seen in those with primary hyperparathyroidism

Answer 7

Renal calculi 
Bone pain  
Polyuria + Polydipsia 
Abdominal pain  
Nausea
Constipation  
Psychological depression  
Lethargy

Question 8

How do patients with primary hyperparathyroidism present?

Answer 8

many have mild hypercalcaemia + may be asymptomatic

Question 9

How do patients with secondary hyperparathyroidism present?

Answer 9

may present with signs/symptoms of HYPOcalcaemia or of the underlying cause (e.g. renal failure, vitamin D deficiency)

Question 10

What investigations should be performed in suspected hyperparathyroidism?

Answer 10

U+Es
Serum calcium (high in primary + tertiary, low/normal in secondary)
Serum phosphate (low in primary + tertiary, high in secondary)
ALP
Vitamin D
PTH
Renal ultrasound: can visualise renal calculi

Question 11

Describe the blood pH in Primary Hyperparathyroidism

Answer 11

Hyperchloraemic acidosis
Normal anion gap
Due to PTH inhibition of renal reabsorption of bicarbonate

Question 12

What can high PTH in the presence of high calcium also be caused by? How do we distinguish this from primary hyperparathyroidism?

Answer 12

Familial hypocalciuric hypercalcaemia (FHH)

Calcium: creatinine clearance ratio <0.01 in FHH

Question 13

How is acute hypercalcaemia managed?

Answer 13

IV fluids
Avoid factors that exacerbate hypercalcaemia (e.g. thiazide diuretics)
Maintain adequate hydration
Moderate calcium + vitamin D intake

Question 14

What surgical treatment options are there for hyperparathyroidism?

Answer 14

Subtotal parathyroidectomy

Total parathyroidectomy

Question 15

How is secondary hyperparathyroidism treated?

Answer 15

Treat underlying cause (e.g. renal failure)

Calcium + vitamin D supplements may be needed

Question 16

List 4 complications of primary hyperparathyroidism

Answer 16

Increased PTH causes:
increased bone resorption  
Increased tubular calcium reabsorption 
Increased 1a-hydroxylation of vitamin D  
All of these lead to hypercalcaemia

Question 17

List 2 complications of secondary hyperparathyroidism

Answer 17

Increased stimulation of osteoclasts + increased bone turnover
This leads to osteitis fibrosa cystica

Question 18

List 2 complications of surgery for hyperparathyroidism

Answer 18

Hypocalcaemia

Recurrent laryngeal nerve palsy

Question 19

What is the prognosis in hyperparathyroidism?

Answer 19

Primary: surgery is curative for benign disease in most cases
Secondary or Tertiary: same prognosis as chronic renal failure