Things to remember about Electrolytes:
Potassium: normal level is 3.5-5.0. Renal failure, acidosis, increased K administration, ACE inhibitors, and potassium-sparing diuretics can cause hyperkalemia. S/S are weakness, paresthesia, respiratory failure. T waves will be tall and peaked, and can lead to first degree AV block. Treat hyperkalemia with Calcium, glucose, insulin, or sodium bicarbonate to shift K from ECF to ICF. Kayexelate is also often given to decrease K levels (causes diarrhea). Hypokalemia can be caused by diuretics (Lasix, Hydrochlorothiazide), DKA, and alkalosis. S/S are weakness, paresthesia, cramps, and constipation. T waves are flat on ECG. Give potassium chloride IV to replace if very low, or just K pills. Good sources of K are chocolate, broccoli, potatoes, and bananas, among others.
Calcium: normal level is 8.0-10.4. Hypercalcemia can be caused by hyperparathyroidism. (Remember that parathyroid hormone and calcitonin do the opposite; PTH increases serum calcium by pulling it out of bones, and calcitonin decreases serum calcium by pulling it back into bones.) S/S of high Ca include weakness, nausea/vomiting, constipation, wide QRS complex, and possibly heart block. Give NaCl to restore fluids and promote diuresis. Give steroids and biphosphates to decrease resorption of Ca from bone. Hypocalcemia can be caused by Vit D deficiency, hypoparathyroidism, and Mg imbalance. S/S include paresthesia, tetany, and positive Trousseau’s and Chvostek’s sign. Also can cause Ventricular arrythmias. Give Calcium Gluconate to treat.
Magnesium: normal level is 1.5-3.0. Hypermagnesemia can result from renal failure or taking too many antacids or laxatives containing Mg. Also, pregnant women receiving Mag Sulfate to prevent seizures/eclampsia may have high Mg, so assess LOC and reflexes. S/S include lethargy, weakness, muscle paralysis, hypotension, decreased reflexes, low heart rate and low BP. Complete heart block can occur. Give Calcium Gluconate to counteract Mg and start NaCl as well. Hypomagnesemia can occur with prolonged diarrhea, malnutrition, loop diuretics, and aminoglycosides. S/S include tremors, seizures, tetany, and increased reflexes. Also can cause ventricular arrhythmias and prolonged PR and QT intervals. Give oral Mg or IV Mg bolus. Check deep tendon reflexes frequently.
Sodium: normal sodium is 135-145. Hypernatremia can result from excessive diuresis or water loss (diuretics or diabetes insipidus), or Cushing’s syndrome. S/S include weakness, thirst, and nausea. Encourage pt to drink water and slowly get Na back to normal. If Na is corrected too rapidly, may lead to cerebral edema. Hyponatremia is caused by retaining too much fluid (CHF, cirrhosis, SIADH). S/S are weakness, fatigue, abdominal cramps, seizures. To treat, hold fluid and give Na.
Ok, so that’s the cold, hard facts about electrolytes. Now I will tell you how I remember them. First, potassium and sodium are on opposite sides of the cell wall (and you though learning about the sodium potassium pump and active transport was useless info…), so, they have an inverse relationship. And they’re the most important electrolytes for muscles to function, so they’re the most important electrolytes for the heart. People can and will have a heart attack if their K or Na is out of balance. This is why people with anorexia and no other health problems will be at high risk for heart attack- because their electrolytes are all out of balance and their heart goes nuts.
To remember Calcium I just remember that when it is low, the patient will have a positive Chvostek’s and Trousseau’s sign. Chvostek’s is when you tap on their cheek and it twitches, and Trousseau’s is when you pump up a BP cuff on their arm and the hand goes nuts.
Also, to remember magnesium, I think of OB. The pregnant woman with hypertension is at risk for seizures, so they give her Mag Sulfate. It sloooowwwsssss down nerve conduction, so her reflexes may be slow. But, her HTN will resolve and she won’t have a seizure. I also learned today while cleaning my bathroom that epsom salt is actually mag sulfate (!). And it is used to relieve muscle pain when you take a bath in it. However, you can dilute it in water too and use it as a laxative. Oh my, all the uses of magnesium sulfate!
Also, Mg and Ca Gluconate inactivate each other!
You may also notice that for almost every electrolyte imbalance, whether it’s high or low, a symptom is ‘weakness’, and you’re like, what? what a vague symptom. Well, it’s because potassium, sodium, and calcium all help muscles contract, and if your muscles can’t contract, you have muscle weakness. Any time this is a patient’s symptom in an NCLEX or test question, suspect an electrolyte imbalance and get a blood sample to check electrolytes.
Well, that’s all the wisdom I have to share about electrolytes! To all my followers, enjoy! :)