Ca/Mg/PO4 Balance

Question 1

What are clinical symptoms of hypo/Hypercalcemia?

Answer 1

Hypo: Increased Nerve and muscle excitability, tetany, arrhythmia

Hyper: Decreased NM excitability, Cardiacproblems

Question 2

What is total plasma calcium?

Answer 2

9-10.5 md/dL

Question 3

How does Ca affect pH in blood?

Answer 3

Increased free Ca++ in. Blood —> Acidosis

Question 4

Where is Calcitonin released from, and what is it’s action?

Answer 4

• Released from thyroid gland

- Promotes Bone mineralization

Question 5

What is Calcitriol, and where is it produced?

Answer 5

• Active form Vitamin D
• Produced in kidneys
• Increases Ca++ Reabsorption from GI tract

Question 6

How do Loop diuretics, Thiazides, and PTH affect CA++ Reabsorption?

Answer 6

Loop diuretics -> Decrease

Thiazides and PTH -> Increase

Question 7

What is the primary and secondary way that Ca++ is absorbed?

Answer 7

Primary: Solvent Drag -> Paracellular transport (80%)

Secondary: Active transport —> Transcellular Ca++ ATPase and Na/Ca antiporter(20%)

Question 8

How does Furosamide affect Calcium?

Answer 8

• Loop diuretic

- Blocks Calcium uptake into cell from lumen

Question 9

How do Thiazides diuretics increase Ca+ Reabsorption?

Answer 9

• Inhibit Na/Cl symport which is linked to Na/K Pump

- Na/Ca exchanger is activated on basolateral membrane which increases Ca Reabsorption

Question 10

How does PTH increase Ca in the blood? (4)

Answer 10

• Activates Osteoclasts for bone reabsorption
• Increases Renal reabsorption
• stimulates Calcitriol —> GI absorption
• Decreases plasma phosphate by increasing excretion of phosphates

Question 11

How does Vitamin D affect Ca/Phosphate levels?

Answer 11

creates absorption of Ca and PO4

Question 12

What are trousseau sign and chvostek sigh?

Answer 12

Trouseau -> Muscle spasm of upper extremity

Chvostek -> Facial nerve tapping -> facial muscle spasm ipsilaterally

Question 13

What is the main cause of hyperparathyroidism?

Answer 13

Adenoma

Question 14

What is nephrolithiasis and nephrocalcinosis

Answer 14

• Death of kidney due to development of calcium oxolate stones

Question 15

What is common in 90% of patients with renal failure? What is the mechanism of it?

Answer 15

Secondary hyperparathyroidsism

Accumulation of phosphate in plasma due to low excretion in kidneys —> Binds CAA decreasing free ionized calcium —> Hypocalcemia

Question 16

What is indicative of Renal osteodystrophy n a radiograph?

Answer 16

• Osteitis fibrosis cystica: Brown tumor “Giant cells” and substitution of bone with CT

Question 17

What are Phosphate binders an what do they treat?

Answer 17

Medications which bind phosphates in the gut so it cannot be absorbed

Treat hyperphosphatemia in chronic renal disease

Question 18

What is a common mistake in hypophosphatemia that can cause further damage?

Answer 18

Infusion of glucose,

Glucose —> Insulin -> glycolysis -> Transport of phosphates into cell

Question 19

A patients presents with Fanconi syndrome, except K levels are normal. What is a likely cause?

Answer 19

Hypophosphataemia

Question 20

What is normal excretion of phosphate?

Answer 20

10%

Question 21

What is the action of phosphatonins?

Answer 21

Inhibit Renal phosphate reabsorption

Question 22

What tole does phosphate play in pH balance?

Answer 22

Serves an a Buffer in Urine and kidneys

Question 23

How does Mg reabsorption differ from other ions?

Answer 23

Primarily reabsorbed in the thick ascending limb

Question 24

What is the most common cause of hypomangnesemia?

Answer 24

Diuretics