Calcium And Phosphorus Flashcards
What are the causes of low ionized calcium?
Alkalosis Blood transfusions Amino glycosides Heparin Fat embolism Magnesium depletion Pancreatitis Renal insufficiency Sepsis
How does magnesium depletion promote hypocalcemia?
By inhibiting parathormone secretion and reducing end-organ responsiveness to parathormone
How does sepsis cause calcium depletion?
No one knows, but it is independent of vasodilation
Why does alkalosis cause low ionized calcium?
It promotes the binding of calcium to albumin
Why does renal insufficiency cause low ionized calcium?
Phosphate retention and decreased vitamin D synthesis
How do you treat hypocalcemia caused by renal insufficiency?
Use antacids to block phosphate absorption in the small bowel
What are the clinical manifestations of hypocalcemia?
Reduced cardiac contractility
Enhanced cardiac and neuromuscular excitability (tetany, hyper reflexes, parenthesias, seizures
Hypotension
What is ionized calcium?
The active form in the blood
What is the level of hypophosphatemia
Less than 2.5 mg/dl
What are the symptoms/signs of hypophosphatemia
AMS
Hemolytic anemia
Arrhythmias
Weakness (inability to wean the vent)
What is the effect of insulin on phosphate?
Intra cellular movement
What are three conditions that can precipitate hypophosphatemia?
- refeeding syndrome
- DKA
- Large decreases in PCO2
