1. Electrolyte Review Use the slide show to test you knowledge of electrolyte balance. Launch the slide show and try to answer the questions.

2. O Mr. Dawson has the following lab results: Na 135 K 5.5 Cl 99 Calcium 9.3 Phosphate 4.0 Magnesium 2 Which values are abnormal? The K level is abnormal. Normal K range is 3.5-5

3. Name the type or category of hyponatremia Serum sodium low Plasma osmolality high Blood glucose high Hypertonic hyponatremia

4. Hypertonic hyponatremia is also called factitious hyponatremia. The serum or plasma osmolality is elevated but not from the sodium level. In this case the elevated glucose level caused an increase in serum osmolality. In response to an elevated serum osmolality water moves into the vascular space. The end result is a more balanced osmolality, but a diluted sodium level. It is called hypertonic hyponatremia because the cause of the problem was a hypertonic blood plasma environment.

5. Name the type or category of hyponatremia Plasma osmolality normal Plasma sodium level low Lipid level very high Isotonic hyponatremia

6. Isotonic hyponatremia is also called pseudohyponatremia. The plasma contains an abnormally high amount of lipids (can also occur with too much albumin or lipoprotein). The lipids occupy vascular space but do not alter serum osmolality. When lab values are run, the proportion of sodium (sodium per unit volume) appears low when in fact they are not. There is just an overabundance of something else in the plasma (proteins or lipids)

7. Key fact: Hyponatremia with a low plasma osmolality requires an assessment of: patient history fluid volume status

8. Name the type of category of hyponatremia Clinical assessment of edema Clinical assessment of ascites Patient history of congestive heart failure Weight gain of three pounds over the last two days Hypervolemic hypotonic hyponatremia

9. Hypervolemic hypotonic hyponatremia is characterized by sodium and water gain or retention where water retention or gain is greater. With congestive heart failure, edema occurs. Fluid moves into the interstitial space from the vascular space resulting in decreased circulating volume. The body responds by stimulating mechanisms to increase retention of sodium and water (think RAAS) with water retention greater than sodium retention. This can also be seen with liver cirrhosis, nephrotic syndrome (severe edema) and severe hypoalbuminemia

10. Name the type of category of hyponatremia Patient has SIADH following surgery No evidence of fluid overload No evidence of dehydration Low plasma osmolality Euvolemic hypotonic hyponatremia

11. Euvolemic hypotonic hyponatremia occurs when sodium levels are diluted by retention of water, but the circulating volume is constant. In SIADH, the kidneys retain water resulting in dilution of sodium levels. This disorder is also seen with: Schizophrenics who suffer from psychogenic thirst. Increase intake in water, kidneys excrete free water results in low serum osmolality and dilute urine. Consumption of low solute fluids can also cause this type of imbalance. Patient drinks low solute fluid, euvolemic state maintained by kidney excretion of free water, but consumption is such that the serum sodium is diluted. An example is a high intake of beer (beer potomania) or tea (tea and toast diet)

12. Name the type or category of hyponatremia Thiazide diuretic use Free water consumption noted to be increased Hypovolemic hypotonic hypontremia

13. Hypovolemic hypotonic hyponatremia starts with a hypovolemic state. In this case the diuretic use causes excess excretion of water. Thiazides are known to also cause excess excretion of sodium. Baro-receptors sense a decreased ECF, kidneys sense decreased renal perfusion and the RAAS is initiated. Body starts to retain water and sodium. Thirst receptor stimulated and patient consumes solute poor fluids (water) further diluting the sodium. Other causes include: adrenal insufficiency, Excessive GI loss where only water is used to replace, and excessive sweating where only water is used as a replacement.

14. Name the type or category of hyponatremia Janie, 21 year old female arrives to the ED with altered mental status and seizures. Her friends mention that prior to arrival in the ED she complained of a headache. They also mention they went to the French Quarter to celebrate her birthday. While at a local bar she consumed ecstasy and a few mixed drinks but made sure to drink plenty of water to stay hydrated while dancing.

15. The patient most likely has hypervolemic hypotonic hyponatremia. The symptoms correlate with a low sodium state. The drug ecstasy is known to stimulate the release of ADH

16. What treatment would Janie receive to normalize her sodium level? Fluid restriction, hypertonic 3% saline infusion, diuretic (loop)

17. A patient with a sodium level of 155 may show symptoms including: Agitation, restlessness, seizures and coma (brain cell shrinking) Increased heart rate, hypotension, weak or thready pulse (decrease in circulating ECF) Dry skin, dry mucous membranes, decreased urine output (water leaves the cells)

18. Acidosis results in which electrolyte imbalance? Hyperkalemia- when acidosis occurs H ions move into the cell pushing K out into the ECF

19. Name two common causes of K loss Diuretic use GI loss