Phys: Electrolyte Disturbance: Ca, Mg, Phosphate

Question 1

Calcium normal range

Answer 1

8.5-10

Question 2

50% of calcium is bound to ______

Answer 2

Albumin

Question 3

Majority of calcium is stored in the __________

Answer 3

Bones

Question 4

Roles of Calcium

Answer 4

Coagulation, cell signaling, muscle contraction, neuromuscular transmission

Question 5

Endocrine regulation of Calcium done by these 2 things

Answer 5

Calcitriol and PTH

Question 6

Hypocalcemia

Answer 6

Causes: eating disorders, chelation therapy, low PTH, low vitamin D, tumor lysis

Clinical presentation: NM irritability, parasthesis (oral, perioral, a real) tingling or pin and needles, tenany, hyperreflexia, laryngospasm

ECG: prolonged QT interval

Question 7

Hypercalcemia

Answer 7

Causes: Excess PTH, excess Vit D, Malignancy

Clinical presentation: constipation, fatigue, lethargy, depression, bone pain, kidney stones, anorexia, nausea, vomiting, pancreatitis

Psychiatric: Depression and confusion

EKG: Short QT interval, widened T wave

Question 8

Renal regulation of Calcium

Answer 8

Kidneys excrete Ca in urine and kidneys are involved in forming Vit D

99% of filtered Ca is reabsorbed

Reabsorption of Ca is tightly coupled to Na

Question 9

What is the major controller of GI calcium absorption?

Answer 9

Vitamin D

Question 10

Ca++ reabsorption is tightly coupled to _______

Answer 10

Na+ reabsorption in the PCT and TALH

Only in the distal tubule is the reabsorption of the two ions dissociated

Question 11

Magnesium normal range

Answer 11

1.5-2.0

Question 12

Mg is a necessary __________ for many enzymed

Answer 12

Cofactor

Question 13

Hypomagnesemia

Answer 13

Caused by: alcoholism, malnutrition, Chron’s disease, Whipple’s disease, celiac sprue

Renal Loss: Bartter’s syndrome, Gitelman syndrome, Loop and thiazide diuretics side effect

Clinical presentation: weakness and muscle cramps, CNS-irritability, hallucinations, depression

EKG: Prolonged PR, QRS, and QT. Tornadoes de pointes, complete heart block and cardiac arrest, Cardiac arrythmias

Question 14

Hypermagnesemia

Answer 14

Causes: cell lysis, hemolysis, tumor cell lysis, renal insufficiency

Clinical presentation: weakness, nausea, vomiting (4.0 mEq/L hyporeflexia)

EKG: arrhythmia and asystole
>5 : prolonged AV conduction
>10: complete heart block
>13 Cardiac arrest

Prolonged PR interval, shortened QT

Question 15

Renal Regulation of Mg

Answer 15

Free component is freely filtered and then handled by the nephron almost identically to Calcium

Question 16

Phosphate normal range

Answer 16

2.3-4.8

Question 17

Phosphate

Answer 17

Necessary cofactor for many enzymes and is a major intracellular anion

Question 18

Endocrine regulation of phosphate

Answer 18

Calcitriol and PTH

Question 19

Hyperphosphatemia

Answer 19

Causes: hypoparathyroidism, chronic renal failure, tumor lysis

Clinical presentation: ectopic calcification

Question 20

Hypophosphatemia

Answer 20

Causes: alcohol abuse, malabsorption

Clinical presentation: muscle dysfunction, respiratory depression, Rhabdomyolysis

Question 21

90-95% f the total plasma phosphate is filterable at the ___________

Answer 21

Renal corpuscle

Question 22

Filtered phosphate is actively reabsorbed in the ________

Answer 22

PCT (75-80%)