Electrolyte Cases

Question 1

1. Quantify sodium content and water content of body compartments in disease states.

Answer 1

ICF volumes are determined by sodium concentration, low serum sodium leads to an increase in ICF fluid

ADH is triggered by low osmolality and very low volumes, it will cause the body to retain more water (decrease serum osmolality)

if a patient is treated with diuretics, depending on the diuretic (loop or thiazide) are K+ wasting

when patients are in heart failure their aldosterone is likely to be high to preserve ECV, and therefore serum osmolality will be high

Question 2

2. Use appropriate serum and urine studies to assess ECF volume status (sodium content)

Answer 2

with the help of aldosterone at low BPs the kidneys will hold on to more Na+ (urine Na+ will be low)

Question 3

3. Explain abnormal potassium handling in the kidney in disease states causing abnormalities in serum potassium concentrations.

Answer 3

low potassium can be demonstrated by generalized weakness

Question 4

What are normal serum sodium and potassium

Answer 4

Na 135-140

K 3.8-4.8

Question 5

What effect do diuretics have on the concentrating power of the loop of Henle?

Answer 5

decreased ability to concentrate urine with loop diuretics because ions cannot be reabsorbed

Question 6

How do you determine the volume status of person with edema and orthopnea.

Answer 6

weight gain tells you if the total volume is up even if intravascular pressure is low