Parathyroid Pathology

Question 1

What are the two cell types that make up the parathyroid?

Answer 1

Chief cells

Oxyphill cells

Question 2

What hormone do Chief cells secrete?

Answer 2

PTH

Question 3

What makes Oxyphill cells pink?

Answer 3

Abundance of mitochondria

Question 4

What are the main functions of PTH?

Answer 4

Increase renal resorption of Ca
Increase urinary PO4 excretion
Increase conversion of Vitamin D –> Dihydroxy form
Release Ca and PO4 from bone

Question 5

What is the most common cause of Primary Hyperparathyroidism?

Answer 5

Parathyroid Adenoma

Question 6

What is the most common cause of asymptomatic hypercalcemia?

Answer 6

Parathyroid Adenoma

Question 7

What molecular defects are found in sporadic Parathyroid Adenomas?

Answer 7

Cyclin D1

MEN1

Question 8

What molecular defects are found in familial Parathyroid Adenomas?

Answer 8

MEN1

RET

Question 9

How many glands does Parathyroid Adenoma typically affect?

Answer 9

1 of the 4

Question 10

Morphology = well-circumscribed, hypercellular (mostly Chief) mass in a single parathyroid gland

Answer 10

Parathyroid Adenoma

Question 11

What disease causes all 4 glands of the parathyroid to be enlarged, even if they are asymmetrically enlarged?

Answer 11

Parathyroid Hyperplasia

Question 12

What do the cells of Parathyroid Carcinoma look like?

Answer 12

Normal parathyroid gland cells

Question 13

How is the Dx of Parathyroid Carcinoma made?

Answer 13

By the presence of invasion or metastases

Question 14

What are the Sx’s of Primary Hyperparathyroidism?

Answer 14

Bones, Stones, Groans (GI), and Moans (Psych)

Question 15

What is the MOA for Secondary Hyperparathyroidism?

Answer 15

Compensatory hypersecretion of PTH due to prolonged hypocalcemia

Question 16

What are some EX’s of Secondary Hyperparathyroidism?

Answer 16

Chronic renal failure
Poor dietary Ca intake
Steatorrhea
Vitamin D deficiency

Question 17

Morphology = Hyperplastic parathyroid gland with metastatic calcifications seen in lungs, heart, stomach, and blood vessels

Answer 17

Secondary Hyperparathyroidism

Question 18

What is Calciphylaxis?

Answer 18

Vascular calcification –> ischemic damage to the skin and other organs

Question 19

What is the MOA of Tertiary Hyperparathyroidism?

Answer 19

Hypersecretion of PTH after the cause of the prolonged hypocalcemia (2˚ Hyperparathyroidism) has been corrected

Question 20

What is the Tx for Tertiary Hyperparathyroidism?

Answer 20

Surgical removal (leave a little for normal physiologic function)

Question 21

What is the Tx for Secondary Hyperparathyroidism?

Answer 21

Vitamin D supplements

PO4 binders

Question 22

What type of inheritance pattern does Familial Hypocalciuric Hypercalcemia have and what is the mutated gene?

Answer 22

AD

Calcium-Sensing Receptor gene (CASR)

Question 23

What are some causes of hypoparathyroidism?

Answer 23

Hypercalcemia of malignancy
Vitamin D toxicity
Immobilization
Thiazide diuretics
Granulomatous disease (Sarcoidosis)

Question 24

What are Brown Tumors?

Answer 24

Microfractures in bone –> secondary hemorrhage –> influx of macrophages and repair with fibrous tissue –> formation of a mass

Question 25

What is Osteitis Fibrosa Cystica?

Answer 25

Increased osteoclast activity, peritrabecular fibrosis, and cystic brown tumors

Question 26

What is Nephrocalcinosis?

Answer 26

Calcification of renal interstitium and tubules

Question 27

What is the most common cause of symptomatic hypercalcemia

Answer 27

Hypercalcemia of malignancy

Question 28

The most common types of tumors causing Hypercalcemia of Malignancy are located where?

Answer 28

Lung Breast Head/Neck Kidneys

Question 29

What hormone typically causes the hypercalcemia in Hypercalcemia of Malignancy?

Answer 29

PTH-Related Peptide (PTHrP)

Question 30

What are the main 4 lab values used to Dx Hypercalcemia of Malignancy?

Answer 30

Hypercalcemia Elevated PTH Hypophosphatemia

Question 31

What is the most common cause of hypoparathyroidism?

Answer 31

Surgically induced

Question 32

What autoimmune issues are associated with hypoparathyroidism?

Answer 32

Chronic mucocutaneous candidiasis | Primary Adrenal Insufficiency (AKA Autoimmune Polyendocrine Syndrome Type-1 [APS1])

Question 33

What mutation is associated with the inherited form of hypoparathyroidism and what type of inheritance pattern does it follow?

Answer 33

GofF of CASR gene | AD

Question 34

Sx's = tetany, mental status change, prolonged QT interval, dental abnormalities in kids

Answer 34

Hypoparathyroidism (hypocalcemia)

Question 35

What disease causes congenital absence of the parathyroid glands?

Answer 35

DiGeorge syndrome

Question 36

What disease is due to end-organ resistance to PTH?

Answer 36

Pseudohypoparathyroidism

Question 37

What would the lab values be for Ca and PO4 in Pseudohypoparathyroidism?

Answer 37

Hypocalcemia | Hyperphosphatemia

Question 38

What would the lab values be for PTH in Pseudohypoparathyroidism?

Answer 38

Normal or elevated PTH

Question 39

In pts with Pseudohypoparathyroidism, which other hormones might the pts have end-organ resistance to?

Answer 39

TSH | FSH/LH