Parathyroid Pathology

Question 1

Describe the pathophysiology of hypocalcaemia?

Answer 1

Neurons are more excitable

Question 2

What are the causes of hypocalcaemia?

Answer 2

Primary hypoparathyroidism

• Total thyroidectomy
• Selective parathyroidectomy
• Post-radiation

Severe vitamin D deficiency

Hypomagnesaemia Mg2+ deficiency

Cytotoxic drug-induced hypocalcaemia

Hypoalbuminaemia

Acute pancreatitis

Pseudohypoparathyroidism

Pseudopseudohypoparathyroidism

Question 3

What is Pseudohypoparathyroidism?

Answer 3

Cells resistant to PTH

Pixie face, short metacarpals and metatarsals

Question 4

What is Pseudopseudohypoparathyroidism?

Answer 4

Same morphological features as pseudohypoparathyroidism, but normal biochemical profile

Question 5

How does hypocalcaemia present?

Answer 5

SPASMODIC

Parathesia

Seizures/tetany

Disorientation/dementia

Dry skin/Impetigo

Muscle twitching/spasms

Question 6

What is Trousseau’s sign?

Answer 6

Wrist spasm

Question 7

What is Chovstek’s sign?

Answer 7

Facial twitching

Question 8

What is Carpopedal Spasm?

Answer 8

Feet or hand spasm

Question 9

What investigations are used in hypocalcaemia diagnosis?

Answer 9

<ca2>

<p>Vitamin D</p>

<p><pth>

<p>Albumin</p>

<p>Magnesium</p>

<p>Phosphorus</p>

<p>ECG: Prolonged QT</p></pth></p></ca2>

Question 10

How is hypocalcaemia managed?

Answer 10

Calcium and Vitamin D supplements

Recombinant human Parathyroid hormone

Question 11

Give complications of hypocalcaemia

Answer 11

Hypotension

HF

Arrythmia

Laryngospasm/Bronchospasm

Question 12

Describe the pathophysiology of hypercalcaemia

Answer 12

Neurons are less excitable

Question 13

What causes hypercalcaemia?

Answer 13

Hyperparathyroidism

• Adenoma
• Carcinoma
• Hyperplasia

Bone Metastasis

• Lung
• Breast

Renal disease

Sarcoidosis

Endocrine

• Acromegaly
• Addisons
• Thyrotoxicosis

Drugs

Dehydration

Familial Hypocalciuric Hypercalcaemia

Question 14

What is the most common cause of hypercalcaemia?

Answer 14

Malignancy is most common in hospital, whereas hyperparathyroidism is most common in the community

Question 15

How does hypercalcaemia present?

Answer 15

Stones, groans, bones and moans

Dehydration: Loss of calcium in urine

Bone pain: De-mineralisation to release Ca2+

Muscle weakness

Polydipsia/polyuria: Diabetes Insipidus

Confusion: Especially in the elderly

Depression

Constipation

Question 16

What investigations are used in hypercalcaemia diagnosis?

Answer 16

>Ca2+

>PTH (can also be normal in primary hyperparathyroidism)

PTH-related peptide

Vitamin D

TFTs

Tumour markers

ECG, shortened QT interval

Imaging

• Bone scan
• CXR
• Mammogram

Question 17

How is hypercalcaemia managed?

Answer 17

IV fluids, first line

Loop diuretics

Parathyroidectomy

Bisphosphonates

Calcimimetics, drugs that imitate calcium

Question 18

When is a parathyroidectomy carried out?

Answer 18

If Ca2+>3mmol/l + symptomatic/renal stones

Question 19

Give an example of a bisphosphonate?

Answer 19

Alendronate

Question 20

What is a complication of hypercalcaemia?

Answer 20

Kidney/gallbladder stones

Question 21

What is secondary hyperparathyroidism?

Answer 21

Raised PTH in response to low calcium

Question 22

What is tertiary hyperparathyroidism?

Answer 22

Prolonged/untreated secondary hyperparathyroidism occuring almost exclusively in patients with kidney disease causing ongoing hyperplasia the gland

Question 23

What causes hyperparathyroidism?

Answer 23

Solitary parathyroid adenoma

Hyperplasia of parathyroid gland

Autoimmune

HIV

DiGeorge

Multiple Endocrine Neoplasia (MEN) Syndromes 1 and 2

Secondary: Renal failure, Vitamin D deficiency

Question 24

What is the most common cause of hyperparathyroidism?

Answer 24

Solitary parathyroid adenoma, 85% of causes

Question 25

How is hyperparathyroidism managed?

Answer 25

High fluid intake * To prevent stone formation Surgical resection of parathyroid gland

Question 26

What is a complication of hyperparathyroidism?

Answer 26

Risk of transient hypocalcaemia post-operatively

Question 27

What conditions are associated with Multiple Endocrine Neoplasia (MEN) 1?

Answer 27

Hyperparathyroidism/parathyroid adenoma Pancreatic * Insulinoma Pituitary

Question 28

What conditions are associated with Multiple Endocrine Neoplasia (MEN) 2?

Answer 28

Hyperparathyroidism Phaechromocytoma Medullary thyroid cancer

Question 29

What electrolyte abnormality is associated with hypercalcaemia?

Answer 29

Hypernatraemia

Question 30

What is important to note about PTH levels in primary hyperparathyroidism?

Answer 30

PTH may be normal

Question 31

What drugs can cause hypercalcaemia?

Answer 31

Thiazide diuretics

Question 32

When is an IV biphosphonate indicated?

Answer 32

Ca over 3 mmoles/l

Question 33

Describe the hormone profile of primary hyperparathyroidism

Answer 33

increased or inappropriately normal PTH increased Ca decreased phosphate increased ALKP

Question 34

Describe the hormone profile of secondary hyperparathyroidism

Answer 34

increased PTH normal or decreased Ca increased phosphate decreased vit D

Question 35

Describe the hormone profile of tertiary hyperparathyroidism

Answer 35

significantly increased PTH normal or increased Ca normal or decreased phosphate normal or decreased vitamind D increased ALKP

Question 36

What x-ray sign can be seen in hyperparathyroidism?

Answer 36

Pepper pot skull

Question 37

How is hypomagnesaemia managed?

Answer 37

\<0.4 mmol/L or tetany, arrhythmias, or seizures * IV magnesium replacement \>0.4 mmol/l * Oral magnesium salts, although diarrhoea can occur