electrolytes

Question 1

where is the largest repository of calcium in the body

Answer 1

skeleton

Question 2

What are the main mechanisms of calcium maintenance

Answer 2

GI absorption of calcium, renal excretion and skeletal remodeling

Question 3

what hormone causes the renal excretion of calcium

Answer 3

calcitonin

Question 4

what other electrolyte is secreted through the calcium-calcitonin pathway

Answer 4

phosphate

Question 5

what hormone is stimulated by low levels of calcium

Answer 5

parathryroid hormone

Question 6

what does PTH do?

Answer 6

causes the increase in osteoclast activation thus increasing calcium levels. it has the opposite effect on serum phosphate and causes the excretion of phosphate.

Question 7

what is the most coimmon cause of hypercalcemia

Answer 7

hyperparathyroidism

Question 8

what is the second leading cause of hypercalcemia

Answer 8

cancer. hyperparathryoidism and cancer acciount for 90% of hypercalcemia cases.

Question 9

what are the five main areas of etiology for hypercalcemia

Answer 9

renal dysfunction, malignancy, hyperparathyroid-related, high bone turnover, and vitamin D related.

Question 10

what are the normal levels of calcium and when do patients start having symptoms of hypercalcemia

Answer 10

normal are between 8-10. symptoms begin usually greater than 12, as mild hypercalcemia does not typically present with symptoms.

Question 11

what are the physical manifestations of hypercalcemia

Answer 11

stones, bones, psychic groan and abdominal moans.
renal calculi, bone pain or arthritis or osteoporosis, poor concentration, weakness, fatigue, stupor, coma, abdominal pain, constipation, nausea, vomiting, pancreatitis and anorexia.
also shortening QT interval and arrhythmias

Question 12

what is a common cause of hypercalcemia that is typically overlooked for someone that has just had surgery

Answer 12

prolonged immobilization can cause hypercalcemia due to massive bone resorption.

Question 13

what is the cause of the vast majority of primary hyperparathyroid cases?

Answer 13

adenoma of one of the four parathyroid glands that causes secretion of PTH.

Question 14

what is the typical presentation of someone with teritary hypercalcemia, which is due to renal failure

Answer 14

initially present with hypocalcemia, hyperphosphetemia and low vit d levels. this leads to hyperplasia of the parathyroid glands and an increase in the levels of PTH, eventually causing hypercalcemia.

Question 15

what are the most serious manifestations of hypercalcemia

Answer 15

coma and arrhythmias

Question 16

what is the definition of hyponatremia

Answer 16

sodium levels less than 135

Question 17

what are the symptoms of hyponatremia

Answer 17

usually asymptomatic, but can be nausea, vomting, lethargy. severe cases presents as confusion, coma, seizures.

Question 18

how do we treat severe hyponatremai

Answer 18

3% sodium IV, needs to be done slowly as to not cause a demyelinating disease.

Question 19

what are some causes of hypovolemic hyponatremia

Answer 19

skin loss, thrid-spacing, GI loss mineralcorticoid deficiency, diuretic use.

Question 20

what are some causes of hypervolemic hyponatremia

Answer 20

exhibit signs of volume expansion, CHF, cirrhosis, nephrosis. treatment is diuretics

Question 21

what are some of the causes of euvolemic hyponetremia

Answer 21

SIADH secretion. water intoxication, hypothyroidism, low solute intake.

Question 22

what are the main causes of hypernatremia

Answer 22

due to net water loss, most likely caused by lack of access to water or impaired thirst response.