Any condition that can cause fluid electrolyte imbalances, such as cardiac, circulatory, endocrine, gastrointestinal or lung disorders, malnutrition, kidney dysfunction, or acid-base imbalance requires frequent monitoring of blood electrolytes (Ambati et al., 2023). Electrolyte evaluation is done through a blood specimen using lithium heparin tubes. Common laboratory ranges will vary slightly depending on location and facility protocols. Table B1 lists common laboratory ranges and clinical manifestations for each electrolyte.
| Electrolyte | Normal Range | Mild to Moderate Range | Complications |
|---|---|---|---|
| Sodium | 135–145 mmol/L | Hyponatremia: 125–135 mmol/L Hypernatremia: 145–160 mmol/L |
May lead to neurological consequences such as seizures |
| Potassium | 3.6–5.5 mmol/L | Mild hypokalemia: < 3.6 mmol/L Moderate hypokalemia: < 2.5 mmol/L Mild hyperkalemia: 5–5.5 mmol/L Moderate hyperkalemia: 5.5–6.5 mmol/L |
May lead to cardiac arrhythmias, fatigue, lethargy, and muscle weakness |
| Calcium | 8.8–10.7 mg/dL | Hypocalcemia: < 8.8 mg/dL Hypercalcemia: > 10.7–11.5 mg/dL |
May lead to cardiac arrhythmias, fatigue, lethargy, and muscle weakness |
| Bicarbonate | 23–30 mmol/L | Acidosis: < 23 mmol/L Alkalosis: > 30 mmol/L Increases or decreases depending on acid-base status either respiratory or metabolic |
Acidosis: may inhibit O2 transport at the cellular level Alkalosis: may cause tetany and paresthesia |
| Magnesium | 1.46–2.68 mg/dL | Hypomagnesemia: < 1.46 mg/dL Hypermagnesemia: > 2.68 mg/dL |
May lead to neurological consequences such as seizures, imbalances, fatigue, lethargy, and muscle weakness |
| Chloride | 95–105 mEq/L | Hypochloremia: < 95 mEq/L Hyperchloremia: > 105 mEq/L |
Hypochloremia may lead to fatigue and weakness Hyperchloremia may lead to high blood pressure, changes in fluid secretion, headache, metabolic acidosis, muscle cramps, arrythmias, and confusion |
| Phosphorus | 3.4–4.5 mg/dL | Hypophosphatemia: < 2.5 mg/dL Hyperphosphatemia: > 4.5 mg/dL |
May lead to bone and muscle disorders and increase risk of cardiovascular and neurological disorders |
Significant variation can occur depending on the cause of each electrolyte imbalance. Many electrolytes are interdependent of one another, meaning that if one is abnormal, it can elicit a chain reaction causing others to become abnormal (Kraut & Madias, 2017). The delicate balance of fluid and electrolytes within the body to maintain homeostasis needs constant and comprehensive evaluation. Table B2 lists the most common causes.
| Electrolyte | Cause |
|---|---|
| Sodium | Hyponatremia: adrenal insufficiency, cirrhosis, chronic hyperglycemia, heart failure, low dietary sodium intake, polydipsia, severe dyslipidemia, and syndrome of inappropriate antidiuretic hormone secretion (SIADH) Hypernatremia: hypertonic IV administration, osmotic diuresis, or unreplaced fluid loss via the skin or gastrointestinal tract |
| Potassium | Hypokalemia: aldosteronism or administration of loop diuretics Hyperkalemia: acute kidney injury, administration of beta blockers, insulin deficiency, metabolic acidosis |
| Calcium | Hypercalcemia: malignancy, hyperparathyroidism, malignancies, or tuberculosis Hypocalcemia: pancreatitis, parathyroid dysfunction, hypomagnesemia, or sepsis |
| Bicarbonate | Increase: metabolic alkalosis or respiratory acidosis Decrease: metabolic acidosis or respiratory alkalosis |
| Magnesium | Hypermagnesemia: ingestion of high amounts of oral magnesium, such as over-the-counter antacids, and renal failure Hypomagnesemia: alcohol use disorder, diuretic administration, or fluid loss such as from excessive vomiting and diarrhea |
| Chloride | Hyperchloremia: administration of excessive IV NS, diarrhea, ingestion of saltwater, and excessive amounts of salt Hypochloremia: excessive vomiting, diarrhea, or other gastrointestinal fluid loss |
| Phosphorus | Hypophosphatemia: parathyroid disorders, and vitamin D deficiency Hyperphosphatemia: kidney injury and parathyroid disorders |
References
Ambati, R., Kho, L. K., Prentice, D., & Thompson, A. (2023). Osmotic demyelination syndrome: novel risk factors and proposed pathophysiology. Internal Medicine Journal, 53(7), 1154–1162. https://doi.org/10.1111/imj.15855
Kraut, J. A., & Madias, N. E. (2017). Adverse effects of the metabolic acidosis of chronic kidney disease. Advances in Chronic Kidney Disease, 24(5), 289–297. https://doi.org/10.1053/j.ackd.2017.06.005
Hoppe, L. K., Muhlack, D. C., Koenig, W., Carr, P. R., Brenner, H., & Schöttker, B. (2018). Association of abnormal serum potassium levels with arrhythmias and cardiovascular mortality: A systematic review and meta-analysis of observational studies. Cardiovascular Drugs and Therapy, 32(2), 197–212. https://doi.org/10.1007/s10557-018-6783-0
Shrimanker, I., & Bhattarai, S. Electrolytes. (2023 Jul 24). StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK541123/