Electrolyte disturbance

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Electrolyte Disturbance Main Page
Patient Information
Overview
Classification Hyponatremia Hypernatremia Hypokalemia Hyperkalemia Hypocalcemia Hypercalcemia Hypophosphatemia Hyperphosphatemia Hypomagnesemia Hypermagnesemia
Causes
Diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Seyedmahdi Pahlavani, M.D. [2]

Synonyms and keywords: abnormal electrolytes, abnormal lytes, lytes

Overview

Electrolytes are electrically charged solutes necessary to maintain body homeostasis. The main electrolytes include Sodium (Na), Potassium (K), Chloride (Cl), Calcium (Ca), Phosphorus (P), and Magnesium (Mg). These electrolytes are involved in multiple physiologic and neurohormonal reactions necessary to maintain neuromuscular, neuronal, myocardial, and acid-base balance. Their balance are mainly regulated by renal and endocrine systems, any changes in their balance may be life threatening. Electrolytes are in balance to achieve neutral electrical charges. Electrolytes could be classified based on their electrical charge to anions and cations. Anions include bicarbonate, chloride, and phosphorus. Cations are calcium, magnesium, potassium, and sodium. Sodium and chloride are the major extracellular ions that has the greatest impact on serum osmolality (solute concentration in 1 liter of water). Calcium and bicarbonate are the other major extracellular electrolytes. Main intracellular electrolytes are potassium, phosphorus, and magnesium.

Causes

The following table summarize the common causes for electrolytes imbalance.

Electrolyte Ionic formula Normal limits (meq/l) Disturbance Lab value Common causes Sodium Na+ 135-145 Hyponatremia <135 meq/L Hypovolemic Renal loss (diuretics) Extrarenal loss (hemorrhage, diarrhea, sweating) Euvolemic SIADH, glucocorticoid deficiency, psychogenic polydipsia Hypervolemic CHF, cirrhosis, nephrotic syndrome, renal failure Hypernatremia >145 meq/L Extrarenal loss Vomiting, diarrhea, insensible loss Renal loss Diuretics, diabetes insipidus (central and nephrogenic) Potassium K+ 3.5-5 Hypokalemia <3.5 meq/L Transcellular shifts Insulin therapy, alkalosis GI loss Diarrhea, laxative abuse, vomiting Renal loss Acidosis: DKA, RTA (I and II) Alkalosis: Bartter's syndrome, Gitelman's syndrome Hyperkalemia >5 meq/L ACE inhibitors, acidosis, addisonian crisis, beta blockers, blood transfusion, cirrhosis, diabetic nephropathy, high potassium diet, malnutrition, renal tubular acidosis type IV, renal failure Calcium Ca2+ 8.5-10.2 Hypocalcemia <8.5 meq/L Hypoparathyroidism, pseudohypoparathyroidism, hypomagnesemia, hypovitaminosis D, chronic kidney disease, hypoalbuminemia Hypercalcemia >10.2 meq/L Hyperparathyroidism, familial hypocalciuric hypercalcemia, malignancy, Milk-alkali syndrome, vitamin D toxicity, sarcoidosis, diuretics, lithium Phosphate PO43- 2.5-4.5 Hypophosphatemia <2.5 meq/L Refeeding syndrome, respiratory alkalosis, alcohol abuse, malabsorption Hyperphosphatemia >4.5 meq/L Transcellular shift, tumor lysis syndrome , rhabdomyolysis, hypoparathyroidism, pseudohypoparathyroidism, acute kidney injury, chronic kidney disease Magnesium Mg2+ 1.5-2.5 Hypomagnesemia <1.5 meq/L Alcohol use, uncontrolled diabetes mellitus, hypercalcemia, Gitelman syndrome, loop and thiazide diuretics Hypermagnesemia >2.5 meq/L Renal failure, massive oral ingestion Diagnosis Diagnosis of electrolyte disturbances is suspected by clinical presentation and will be confirmed by laboratory values. Clinical manifestations depends on the severity of disturbances and their chronicity however, the presentation may vary according to underlying condition. The following table summarize common symptoms and signs of electrolytes disturbances and important ECG findings. Disturbance Chronicity/ Level (meq/L) Common clinical manifestations ECG findings Symptoms Signs Hyponatremia Early/125-130 Nausea, malaise Muscle cramps N/A Late/115-120 Headache, lethargy respiratory distress, coma, seizure Non specific St-T changes Hypernatremia >145 Malaise Lethargy, confusion, coma Non specific St-T changes Hypokalemia <2.5-3 Nausea, anorexia, vomiting, muscle weakness, muscle cramps Rhabdomyolysis, respiratory failure ECG changes: ST depression, decrease in T wave amplitude, U wave, QT prolongation Arrhythmia: PAC, PVC, sinus bradycardia, paroxysmal atrial or junctional tachycardia, atrioventricular block, and ventricular tachycardia or fibrillation Hyperkalemia >7.5 Muscle weakness, polyuria, polydipsia Paralysis ECG changes (in order of severity): Tall peaked T, shortened QT interval, prolongation of PR interval and QRS duration, P wave disappearance, QRS widening, sine wave Arrhythmia:  Sinus bradycardia, sinus arrest, slow idioventricular rhythms, ventricular tachycardia, bundle branch blocks, ventricular fibrillation, and asystole Hypocalcemia <7-7.5 Paresthesias, muscle spasm Trousseau's sign, Chvostek's sign, seizures ECG changes: QT interval prolongation, QRS shortening Arrhythmia: Sinus bradycardia, AV block Hypercalcemia >12 Fatigue, depression, insomnia, nausea, vomiting, constipation, polyuria Hyperreflexia, confusion, coma ECG changes: QT interval shortening Arrhythmia: Supraventricular or ventricular arrhythmias Hypophosphatemia <1 Irritability, paresthesias, dysphagia Delirium, seizure, coma Ventricular arrhythmias Hyperphosphatemia >4.5 Muscle cramps, paresthesias Tetanus QT interval prolongation (mainly due to associated hypocalcemia) Hypomagnesemia <1 Tremor, tetanus, weakness Apathy, delirium, coma ECG changes: QRS widening, peaked T waves, increased PR interval Arrhythmia: Atrial and ventricular arrhythmias Hypermagnesemia >4 Nausea, flushing, headache Somnolence, hypotension, absent DTR ECG changes: P-R interval prolongation, increased QRS duration, Q-T interval prolongation Arrhythmia: Complete heart block References Related Chapters Acidosis Alkalosis Dehydration Malnutrition Starvation Template:WikiDoc Sources