Quick facts
Both high and low sodium show up as neurological changes
- Low sodium moves water into brain cells and they swell, so expect headache, confusion and seizures. Without treatment, very low sodium can lead to coma.[2][4]
- High sodium pulls water out of cells, and the effect is most noticeable in the brain: confusion, irritability, lethargy and even seizures, along with intense thirst and sticky mucous membranes.[2]
Think about water first: lost water raises sodium, extra water dilutes it
- High sodium usually comes from water loss, such as too little fluid intake, vomiting or diarrhea. As fluid is lost and sodium climbs, serum osmolality rises too.[2]
- Low sodium can follow too much water or too much hypotonic IV fluid. Heart failure, kidney disease, cirrhosis and some medicines, such as many nonprescription pain relievers and some antidepressants, can also lower it.[2][4]
- Treatment of low sodium depends on the cause and often means limiting water or stopping hypotonic IV fluid. If hyponatremia is severe, prescribed hypertonic saline raises sodium gradually.[2]
Diuretics can drop sodium along with potassium
- For patients on diuretics, watch for fluid volume deficit and for both low sodium and low potassium.[2]
Sodium and the rest of the panel are in the Basic metabolic panel flashcard deck. Find the deck in the free app preview.
Open the free app previewHow it shows up on nursing exams
Practice question
A 72-year-old patient admitted with pneumonia has a serum sodium of 127 mEq/L this morning, down from 137 mEq/L yesterday. The laboratory reference range is 136 to 145 mEq/L. The patient is newly confused and reports a headache. Blood pressure is 126/78 mm Hg, heart rate 86/min, respiratory rate 18/min, and SpO2 95% on room air. Furosemide and acetaminophen are scheduled now. Which action should the nurse take first?
- A. Offer the patient extra water to drink
- B. Report the sodium drop and new confusion
- C. Give the furosemide dose scheduled now
- D. Recheck the sodium level with tomorrow's labs
Show the answer and why
Correct answer: B. Report the sodium drop and new confusion
- A. Incorrect. Excess water intake is a cause of hyponatremia, so more water could lower the sodium further.
- B. Correct. The sodium is below 136 and falling, and headache and confusion are neurological signs of hyponatremia, which can also cause seizures and coma. The provider needs this change now.
- C. Incorrect. Diuretics are a cause of hyponatremia, so giving the dose before the new low sodium and confusion are reported could make the problem worse.
- D. Incorrect. Waiting a day delays care for a sodium that is falling with new neurological signs. Very low sodium can become life-threatening without treatment.
Sources for this question: [1][2][4]
Memory hook: Sodium problems are water problems, and the warning signs are neurological.