Chapter 23 Parathyroid

Front 1

What is the embryonic derivation of the superior parathyroid glands?

Back 1

4th pouch

Front 2

What is the embryonic derivation of the inferior parathyroid glands?

Back 2

3rd pouch

Front 3

most common ectopic site for parathyroid gland

Back 3

tail of the thymus

Front 4

blood supply to both superior and inferior parathyroid glands

Back 4

Inferior thyroid artery

Front 5

increases serum calcium
increases kidney Ca reabsorption in the distal convoluted tubule, increases OSTEOCLAST, increase Vit D in the kidney

Back 5

PTH

Front 6

Increases intestinal Ca and P04 absorption by increasing calcium-binding protein

Back 6

Vitamin D

Front 7

decrease serum Ca

Back 7

Calcitonin
by osteoclast inhibition
increased urinary excretion of Ca and PO4

Front 8

name the disease.
Women, older age
• Due to autonomously high PTH
• Dx: increased Ca, decreased phosphorus; Cl- to phosphorus ratio > 33, increased renal cAMP, HC03-
secreted in urine
• Can get hyperchloremic metabolic acidosis
• Osteitis fibrosa cystica (brown tumors) - bone lesions from Ca resorption

Back 8

PRIMARY HYPERPARATHYROIDISM

Front 9

Indications for surgery with PRIMARY HYPERPARATHYROIDISM

Back 9

symptomatic disease or asymptomatic disease with
Ca > 13 decreased Cr clearance, kidney stones, substantial loss of bone mass

Front 10

Tx for Parathyroid CA

Back 10

radical parathyroidectomy ( need to take ipsilateral
thyroid )

Front 11

Tx for Parathyroid Adenoma

Back 11

resection; inspect other glands to rule out hyperplasia or multiple adenomas

Front 12

tx of Parathyroid hyperplasia

Back 12

Do not biopsy all glands 2/2 risks hemorrhage and hypoparathyroidism
• Resect 3.5 glands or total parathyroidectomy and auto implantation

Front 13

What is the 1/2 life of PTH?

Back 13

10 min

Front 14

most common ectopic location
of parathyroid gland.

Back 14

thymus

Front 15

what most commonly causes Persistent hyperparathyroidism (1 %)

Back 15

missed adenoma
remaining in the neck

Front 16

Will have preferential uptake by the overactive parathyroid gland
• Good for picking up adenomas but not 4-gland hyperplasia
• Best for trying to pick up ectopic glands

Back 16

Sestamibi-technetium-99

Front 17

Seen in patients with renal failure
• increased PTH in response to low Ca
Most do not need surgery ( 90%)
• Ectopic calcification and osteoporosis can occur

Back 17

SECONDARY HYPERPARATHYROIDISM

Front 18

Tx of SECONDARY HYPERPARATHYROIDISM

Back 18

control diet P04
sx indicated with bone pain

Front 19

• Renal disease now corrected with transplant but still overproduces PTH
• Has similar lab values as primary hyperparathyroidism (hyperplasia)
• Tx: subtotal ( 3.5 glands) or total parathyroidectomy with autoimplantation

Back 19

TERTIARY HYPERPARATHYROIDISM

Front 20

Patients have increased serum Ca and decreased urine CA (should be increased if hyperparathyroidism)
• Caused by defect in PTH receptor in distal convoluted tubule of the kidney that
causes increased resorption of Ca
• Dx: Ca 9-11, normal PTH (30-60), decreased urine Ca
• Tx: nothing (Ca generally not that high in these patients);

Back 20

FAMILIAL HYPERCALCEMIC HYPOCALCIURIA

Front 21

defect in PTH receptor in the kidney, does not respond to PTH

Back 21

PSEUDO HYPOPARATHYROI DISM

Front 22

Rare cause of hypercalcemia
• 50% 5-year survival rate
• Mortality is due to hypercalcemia
increased Ca, PTH, and alkaline phosphatase (can have extremely high Ca levels)
• Lung most common location for metastases
• Tx: wide enbloc excision (parathyroidectomy and ipsilateral thyroidectomy)
• Recurrence in 50%

Back 22

PARATHYROID CANCER

Front 23

Describe MEN I

Back 23

1. Parathyroid hyperplasia
2. Pancreatic islet cell tumors
3. Pituitary adenoma

Front 24

Describe MEN IIa

Back 24

1. Parathyroid hyperplasia
2. Pheochromocytoma
3. Medullary CA of thyroid

Front 25

Describe MEN lIb

Back 25

1. Pheochromocytoma
2. Medullary CA of thyroid
3. Mucosal neuromas
4. Marfan's habitus, musculoskeletal abnormalities

Front 26

• Parathyroid hyperplasia
-Usually the first part to become symptomatic; urinary symptoms, Tx: 4-gland resection with autotransplantation
• Pancreatic islet cell tumors
- Gastrinoma #1, 50% multiple, 50% malignant major morbidity of syndrome
• Pituitary adenoma
- Prolactinoma #1
• Need to correct hyperparathyroidism 1 st

Back 26

MEN I

Front 27

• Parathyroid hyperplasia
• Pheochromocytoma
- Very often bIlateral, nearly always benign
• Medullary CA of thyroid
- Nearly all patients; diarrhea most common symptom; often· bilateral
- #1 cause of death
- Usually 1st part to be symptomatic
• Need to correct pheochromocytoma 1st

Back 27

MEN lla

Front 28

• Pheochromocytoma
-Very often bilateral, nearly always benign
• Medullary CA of thyroid
- #1 cause of death in these patients
• Usually 1st part to be symptomatic
• Mucosal neuromas
• Marfan's habitus, musculoskeletal abnormalities
• Need to correct pheochromocytoma 1st

Back 28

MEN IIb

Front 29

Gene causing MEN I

Back 29

MENIN gene

Front 30

Gene causing MEN II

Back 30

RET proto-oncogene

Front 31

Drug that inhibits osteoclasts (used with malignancies or failure of conventional
treatment); has hematologic, liver, and renal side effects

Back 31

Mithramycin

Front 32

Tx of Hypercalcemic crisis

Back 32

usually secondary to another surgery
Tx: fluids, furosemide, dialysis

Front 33

release PTHrp; can cause hypercalcemia

Back 33

Breast CA metastases to bone
Small cell lung CA
this is not due to bone destruction
Associated with increased urinary cAMP (from action of PTHrp on kidney)

Front 34

malignancy that cause bone destruction; can also increase Ca and urinary cAM P will below

Back 34

Hematologic malignancies