Parathyroid

Question 1

What is the function if PTH ?

Answer 1

🔺free Ca in the blood
- 🔝Ca & PO4 absorption in GIT
- 🔝 Ca & PO4 from bone resorption
- 🔝 Ca reabsorption from DCT
- ⬇️ PO4 reabsorption in PCT
🟢 activate 1a-hydroxylase » 🔝 calcitriol

Question 2

PTH:
[…] serum Ca
[…] serum PO4
[…] urine PO4
[…] urine cAMP

Answer 2

🔺 serum Ca
🔻 serum PO4
🔺 urine PO4
🔺 urine cAMP

Question 3

How serum ions affects regulation of PTH secretion?

Answer 3

🔻 serum Ca » 🔝 PTH secretion
🔺 serum PO4 » 🔝 PTH secretion
🔻 serum Mg » 🔝 PTH secretion
🔻🔻 serum Mg » ⬇️ PTH secretion

Question 4

Changes in blood […] alter PTH by affecting ionizing Ca concentration

Answer 4

pH
🔺 pH: albumin bind ionized Ca 🔺PTH
🔻pH:🔻 PTH

Question 5

1° hypoparathyroidism
[…] PTH […] Ca […] PO4

Answer 5

🔻 PTH 🔻 Ca 🔺 PO4
#surgical resection
#autoimmune / Di-George

Question 6

PTH-independent hypercalcemia
[…] PTH […] Ca […] PO4

Answer 6

🔻 PTH 🔺 Ca 🔻 PO4
#malignancy
# 🔝Ca intake
# 🔝 Vitamin D

Question 7

1° hyperparathyroidism
[…] PTH […] Ca […] PO4

Answer 7

🔺 PTH 🔺 Ca 🔻 PO4
#adenoma (80%)
#hyperplasia (15%)
#carcinoma

Question 8

2° hyperparathyroidism
[…] PTH […] Ca […] PO4

Answer 8

🔺 PTH 🔻 Ca 🔺 PO4
#CKD
#VitD deficiency

Question 9

3° hyperparathyroidism
[…] PTH […] Ca […] PO4

Answer 9

🔺 PTH 🔺 Ca 🔻 PO4
#autonomous (refractory) sHPT due CKD

Question 10

Hypoparathyroidism manifestations:

Answer 10

• Neuromuscular (tetany, paresthesia, seizure, 🔝DTR)
• Cataract
• Arrhythmia
• Osteomalacia

Question 11

Carpal spasm with occlusion of brachial artery with BP cuff

Answer 11

Trousseau sign
HypoCalcemia

Question 12

Contraction of facial muscles with tapping facial nerve

Answer 12

Chovstek sign
HypoCalcemia

Question 13

What are the manifestations of HyperCalcemia ?

Answer 13

-Stones (renal stones)
-Thrones (polyuria)
-Groans (abdominal pain)
-Bones (bone pain)
-Psychiatric overtone (depression, anxiety, insomnia ..)

Question 14

Most common cause of 1° hyperparathyroidism : […]

Answer 14

Adenoma

Question 15

Primary Hyperparathyroidism may be associated with […] syndrome

Answer 15

MEN 1 or 2a

Question 16

End organ resistance to PTH
Due to imprinted GNAS gene
PE: Albright hereditary osteodystrophy

Answer 16

Pseudohypoparathyroidism type 1A

Question 17

Defective G-coupled Ca-sensing receptors

Answer 17

Familial hypocalciuric hypercalcemia

Question 18

What is the effect of Cinacalcet

Answer 18

Senacalcet 🔻Ca
Sensitize Calcium-sensing receptor in parathyroid to Ca » ⬇️PTH

Question 19

What is the effect of Sevelamer

Answer 19

🔻PO4
Prevent phosphate absorption from GIT

Question 20

Indications of parathyroidectomy in 1° HPT

Answer 20

1. 🔺HyperCa
2. 🦴Skeletal indications
   
   • osteoporosis
   • Hx vertebral fracture
3. 🧻Renal indications
   
   • eGFR <60
   • 24hr urine Ca >400
   • nephrolothiasis
4. 👱🏻Age <50 yr

Question 21

What is the recommended age to start screening for osteoporosis ?

Answer 21

👵🏻 65
👴🏻 70