Parathyroid Pathology

Question 1

What are the causes of primary hyperparathyroidism?

Answer 1

Adenoma
Hyperplasia of all 4 glands. MEN
Two adenomas
Parathyroid carcinoma

Question 2

Explain features and causes of secondary hyperparathyroidism

Answer 2

Increased secretion of PTH in response to low calcium because of kidney, liver or bowel diseaseor low Vit D. PTH will be high, calcium will be low, ALP will be high and phosphate will be high in CKD or pseudohypoparathyroidism

Question 3

What is the cause of tertiary hyperparathyroidism?

Answer 3

Autonomous secretion of PTH usually because of chronic kidney disease (prolonged secondary hyperparathyroidism).Occurs once secondary hyperparathyroidism is treated. Hyperplasia of glands continue to secrete PTH
Managed via cinacalcet

Question 4

What are signs of hypercalcaemia

Answer 4

Moans, stones, groans and psychiatric moans.
Painful bones
Renal stones
Abdominal groans: Nausea, vomiting, constipation, indigestion
Psychiatric moans: lethargy, fatigue, memory loss, psychosis and depression

Question 5

What are features of primary hypoparathyroidism

Answer 5

Decreased PTH secretion which can be secondary to thyroid surgery.
There will be low calcium and high phosphate.
It is treated with alfacalcidol.

Question 6

What are symptoms of hypocalcaemia?

Answer 6

• Tetanty (muscle twitching, cramping and spasms),
• Perioral parasthesia,
• Trousseau’s sign (carpal spasm in bronchial artery occluded),
• Chvostek’s sign (tapping over parotid causes facial muscles to twitch)
• QT prolongation
• Depression and cataracts

Use the mnemonic ‘SPASMODIC’:
S – Spasms (Trousseau’s sign)
P – Perioral parasthaesia
A – Anxiety/Irritability
S – Seizures
M – Muscle tone increase (colic, dysphagia)
O– Orientation impairment (i.e. confusion)
D – Dermatitis
I – Impetigo herpetiformis
C – Chvostek’s sign
ECG shows prolonged QTc

Question 7

What is psudohypoparathyroidism?

Answer 7

Target cells are insensitive to PTH.
Associated with low IQ, shoer stature.
Diagnosis made by measuring urinary cAMP and phosphate levels. In pseudohypoparathyroidism these will be normal except type 2 cAMP will be high. In hypoparathyroidism will be high