Ca/Mg/PO4 Balance Flashcards
What are clinical symptoms of hypo/Hypercalcemia?
Hypo: Increased Nerve and muscle excitability, tetany, arrhythmia
Hyper: Decreased NM excitability, Cardiacproblems
What is total plasma calcium?
9-10.5 md/dL
How does Ca affect pH in blood?
Increased free Ca++ in. Blood —> Acidosis
Where is Calcitonin released from, and what is it’s action?
- Released from thyroid gland
- Promotes Bone mineralization
What is Calcitriol, and where is it produced?
- Active form Vitamin D
- Produced in kidneys
- Increases Ca++ Reabsorption from GI tract
How do Loop diuretics, Thiazides, and PTH affect CA++ Reabsorption?
Loop diuretics -> Decrease
Thiazides and PTH -> Increase
What is the primary and secondary way that Ca++ is absorbed?
Primary: Solvent Drag -> Paracellular transport (80%)
Secondary: Active transport —> Transcellular Ca++ ATPase and Na/Ca antiporter(20%)
How does Furosamide affect Calcium?
- Loop diuretic
- Blocks Calcium uptake into cell from lumen
How do Thiazides diuretics increase Ca+ Reabsorption?
- Inhibit Na/Cl symport which is linked to Na/K Pump
- Na/Ca exchanger is activated on basolateral membrane which increases Ca Reabsorption
How does PTH increase Ca in the blood? (4)
- Activates Osteoclasts for bone reabsorption
- Increases Renal reabsorption
- stimulates Calcitriol —> GI absorption
- Decreases plasma phosphate by increasing excretion of phosphates
How does Vitamin D affect Ca/Phosphate levels?
creates absorption of Ca and PO4
What are trousseau sign and chvostek sigh?
Trouseau -> Muscle spasm of upper extremity
Chvostek -> Facial nerve tapping -> facial muscle spasm ipsilaterally
What is the main cause of hyperparathyroidism?
Adenoma
What is nephrolithiasis and nephrocalcinosis
- Death of kidney due to development of calcium oxolate stones
What is common in 90% of patients with renal failure? What is the mechanism of it?
Secondary hyperparathyroidsism
Accumulation of phosphate in plasma due to low excretion in kidneys —> Binds CAA decreasing free ionized calcium —> Hypocalcemia
What is indicative of Renal osteodystrophy n a radiograph?
- Osteitis fibrosis cystica: Brown tumor “Giant cells” and substitution of bone with CT
What are Phosphate binders an what do they treat?
Medications which bind phosphates in the gut so it cannot be absorbed
Treat hyperphosphatemia in chronic renal disease
What is a common mistake in hypophosphatemia that can cause further damage?
Infusion of glucose,
Glucose —> Insulin -> glycolysis -> Transport of phosphates into cell
A patients presents with Fanconi syndrome, except K levels are normal. What is a likely cause?
Hypophosphataemia
What is normal excretion of phosphate?
10%
What is the action of phosphatonins?
Inhibit Renal phosphate reabsorption
What tole does phosphate play in pH balance?
Serves an a Buffer in Urine and kidneys
How does Mg reabsorption differ from other ions?
Primarily reabsorbed in the thick ascending limb
What is the most common cause of hypomangnesemia?
Diuretics
