Path 7 Parathyroid

Question 1

Normal parathyroid histo

Answer 1

Chief cells and fat

Question 2

PTH regulation

Answer 2

++ low free Ca

– high free Ca

Question 3

PTH function (4)

Answer 3

• Increase osteoclast activity
• Increase Vitamin D activation -> small bowel Ca, PO4 reabsorption
• Increase renal Ca reabsorption (distal)
• Increase renal PO4 excretion (proximal)

Question 4

Primary hyperparathyroidism

Answer 4

Hypercalcemia (usually asymptomatic)

• Painful Bones (osteitis fibrosa cystica)
• Renal Stones
• Abdominal Groans (const, ulcer, gall, pancreatitis)
• Psychic Moans

Question 5

Primary hyperparathyroidism lab

Answer 5

• High PTH
• High Ca
• Low PO4
• High urinary cAMP
• High Alkaline Phosphatase

Question 6

Main cause of hyperparathyroidism

Answer 6

Adenoma (95%)

Question 7

Main cause of hyperthyroidism

Answer 7

Graves

Question 8

Parathyroid adenoma mutations

Answer 8

Cyclin D1

MEN1

Question 9

Parathyroid adenoma familial syndromes

Answer 9

MEN-1
MEN-2
Familial hypocalciuric hypercalcemia: (decreased Ca sensitivity)

Question 10

Parathyroid adenoma histo

Answer 10

Packed with uniform polygonal chief cells, involves one gland

Question 11

Primary parathyroid hyperplasia

Answer 11

Looks like adenoma but involves all 4 glands

-Can be associated to MEN

Question 12

Secondary hyperparathyroidism

Answer 12

Caused by chronic hypocalcemia (renal failure)

Question 13

Primary v secondary hyperparathyroidism

Answer 13

High v Low serum Ca

Question 14

Calciphylaxis

Answer 14

Calcification of vessel walls -> ischemic damage to skin & organs

Question 15

Renal osteodystrophy

Answer 15

High PTH levels cause bone resorption

Question 16

Tertiary hyperparathyroidism

Answer 16

Parathyroid becomes autonomous after chronic secondary hyperparathyroidism

• Hypercalcemia
• Tx with parathyroidectomy

Question 17

Congenital hypoparathyroidism

Answer 17

DiGeorge syndrome

Question 18

DiGeorge syndrome

Answer 18

CATCH-22

• Cardiac abnormality (fallot)
• Abnormal facies
• Thymic aplasia
• Cleft palate
• HypoT/HypoPT (aplasia)
• chromosome 22q11

Question 19

Hypoparathyroidism (hypocalcemia) clinical (4)

Answer 19

• Long QT interval
• Calcifications of basal ganglia and lens
• Mental status changes
• Muscle tetany/spasms

Question 20

Hypocalcemia clinical signs

Answer 20

Chvostek sign: facial nerve tapping -> contraction

Trousseau sign: Blood pressure cuff -> carpal spasms

Question 21

Pseudohypoparathyroidism

Answer 21

End-organ resistance to PTH

• Short 4th, 5th digits
• May show resistance to TSH, FSH/LH as well

Question 22

Pseudohypoparathyroidism labs

Answer 22

• Normal or high PTH
• Low serum Ca
• High serum PO4