1. Electrolytes
Part 1

2. Case Study
A sixty-seven year old white male was found pulseless and resuscitated; then brought to the emergency room. He had been reported to be drinking in a bar all afternoon, and had then fallen from a ten foot balcony to snow covered ground. He arrived in the emergency room with a fractured occiput and was unresponsive.
Admission Lab. results:
mEq = mg x valence /atomic, molecular or formula weight
Na=143 mEq/l
( )
BUN=4 mg/dL
(6 – 20)
pH=7.30
(7.35 – 7.45)
Cl=105 mEq/l
(95-105)
GLU=104 mg/dL
Osmolality=356 mOsm/kg
(275 – 295)
M. Zaharna Clin. Chem. 2009

3. Osmolal Gap= measured osmolality - calculated osmolality
Case Study
Cal. Osmo. = (2 X 143) + (104/20) + (4/3)
= = 293
Osmolal Gap= measured osmolality - calculated osmolality
= 356 – 293 = 63
An OG value greater than 15 is considered a critical value
The presence of low blood pH, elevated anion gap and greatly elevated OG is a medical emergency that requires prompt treatment
M. Zaharna Clin. Chem. 2009

4. M. Zaharna Clin. Chem. 2009

5. Prolonged diuretic use can lead to magnesium loss.
Hypokalemia, hypocalcemia, and hypomagnesemia are all possible causes for cardiac arrhythmia.
Prolonged diuretic use can lead to magnesium loss.
M. Zaharna Clin. Chem. 2009

6. Hypomagnesemia can cause decreased levels of potassium and calcium.
The exact mechanism for hypokalemia is not completely understood; however, it is known that magnesium is required for normal Na+ -K+ pump activity, which is responsible for active transport of K +
Magnesium deficiency can impair PTH release and target tissue response, leading to hypocalcemia.
M. Zaharna Clin. Chem. 2009

7. Providing magnesium therapy alone may correct the hypokalemia and hypocalcemia.
Replenishment of either potassium or calcium alone often does not remedy the disorder unless magnesium therapy is provided.
M. Zaharna Clin. Chem. 2009