Sodium and Potassium Imbalance

Definition/Etiology:

• Hypernatremia: Rise in serum sodium above 145. Results from a deficit in water, like in dehydration, or, less commonly, an excess of sodium. One of the common contributing factors is the patient’s inability to obtain adequate fluids. Failure to replenish during extreme heat or episodes of vomiting and diarrhea are also seen as causes.

• Hyponatremia: Decrease in serum sodium below 135. Can result from excessive water gain such as in heart failure or excessive renal sodium loss.

• Hyperkalemia: an elevation in serum potassium level above 5.5. Primary cause is usually some sort of renal dysfunction causing decreased renal excretion.

• Hypokalemia: A decrease in the serum potassium below 3.5. Causes include:
  • Alcohol use (excessive)
  • Chronic kidney disease
  • Diabetic ketoacidosis
  • Diarrhea
  • Diuretics (water retention relievers)
  • Excessive laxative use
  • Excessive sweating
  • Folic acid deficiency
  • Primary aldosteronism
  • Some antibiotic use
  • Vomiting

Pathophysiology:

• Hypernatremia: hypernatremia can only develop as a result of either a loss of free water or a gain of sodium or a combination of both. Hypernatremia by definition is a state of hyperosmolality, because sodium is the dominant extracellular cation and solute

• Hyponatremia: Too much water in your body causes your blood to become watered down. A good example is people who run in long races or run-on hot days. They lose both salt and water in their sweat and often replace these losses with mostly water. This combination can be deadly because it dilutes the remaining sodium in the body.

• Hyperkalemia: Hyperkalemia may result from an increase in total body potassium secondary to imbalance of intake vs. excretion or from maldistribution between intra- and extracellular space

• Hypokalemia: An acute increase in osmolality causes potassium to exit from cells. An acute cell/tissue breakdown releases potassium into extracellular space

Clinical Presentation:

• Hypernatremia: Lethargy, confusion, abnormal speech, irritability, seizures, nystagmus, Orthostatic blood pressure changes, tachycardia, oliguria, dry oral mucosa, abnormal skin turgor, dry axillae, weight loss, and generalized weakness

• Hyponatremia: Muscle cramps or weakness. Nausea and vomiting. Lethargy, or low energy. Headache. Mental status changes, stupor, seizures

• Hyperkalemia: Biggest concern is cardiac involvement – PEAKED T waves! Abd pain, chest pain, palpitations, N/V, weakness.

• Hypokalemia: Constipation. Palpitations, fatigue, muscle weakness, tingling or numbness.

Collaborative Management:

For all of these conditions, diagnostics are basically the same: EKG, and labs. Making sure to draw the specific serum lab we are looking to evaluate. Cardiac monitoring is a must with all of these conditions as any of them, in their severe state, can cause dysrhythmias.

• Hypernatremia: Decrease the serum sodium.
  Fluid replacement with hypo-osmolar solution – D5 or D5-½ NS.
  Treat underlying condition

• Hyponatremia: Most common treatment is fluid restrictions. If severe hyponatremia – talking like down to 120s, might consider hypertonic solution like 3%NS either as a bolus or temporary infusion.

• Hyperkalemia: I think we know most of this. D50 (causes K+ back into the cells) IV, Insulin (offsets the D50), Calcium gluconate (blocks neuromuscular and cardiac effects), Bicarb (treats metabolic acidosis) and Kayexalate (just for fun… increases fecal excretion of K+)

Evaluation | Patient Monitoring | Education:

• Are the electrolytes returning to their baseline numbers and are the patients symptoms subsiding?
• With all of these, nutritional education will prove beneficial.

Linchpins: (Key Points)

• What do we have? – identify the abnormality
  Labs Labs Labs – only way we can see what we have.
• See if interventions are effective