39.1: Appendix B- Major Fluid and Electrolyte Imbalances

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

Table B1 Electrolyte Imbalances (Hoppe et al., 2018)

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

Table B2 Common Causes of Electrolyte Imbalances (Shrimanker & Bhattarai, 2023)

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. 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]. www.ncbi.nlm.nih.gov/books/NBK541123/