Electrolyte disturbance: Difference between revisions
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| | |[[Congestive heart failure|CHF]], [[cirrhosis]], [[nephrotic syndrome]], [[Renal insufficiency|renal failure]] | ||
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Revision as of 18:17, 29 May 2018
For patient information, click here
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Electrolyte Disturbance Main Page | |
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Patient Information |
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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
| Electrolyte | Ionic formula | Normal limits (mg/dl) | Disturbance | Common causes | |||
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| Sodium | Na+ | 135-145 | hyponatremia | Hypovolemic |
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| Euvolemic | SIADH, glucocorticoid deficiency, psychogenic polydipsia | ||||||
| Hypervolemic | CHF, cirrhosis, nephrotic syndrome, renal failure | ||||||
| hypernatremia | Extrarenal loss | Vomiting, diarrhea, insensible loss | |||||
| Renal loss | Diuretics, diabetes insipidus (central and nephrogenic) | ||||||
| Potassium | K+ | 3.5-5 | hypokalemia | Transcellular shifts | Insulin therapy, alkalosis | ||
| GI loss | Diarrhea, laxative abuse, vomiting | ||||||
| Renal loss |
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| hyperkalemia | |||||||
| Calcium | Ca2+ | 8.9-10.1 | hypocalcemia | ||||
| hypercalcemia | |||||||
| Phosphate | PO43- | 2.5-4.5 | hypophosphatemia | ||||
| hyperphosphatemia | |||||||
| Magnesium | Mg2+ | 1.5-2.5 | hypomagnesemia | ||||
| hypermagnesemia | |||||||
- Drug side effect: Hydrochlorothiazide, Pergolide
Table of common electrolyte disturbances
Electrolyte Abnormalities and ECG Changes
The most notable feature of hyperkalemia is the "tent shaped" or "peaked" T wave. Delayed ventricular depolarization leads to a widened QRS complex and the P wave becomes wider and flatter. When hyperkalemia becomes severe, the ECG resembles a sine wave as the P wave disappears from view. In contrast, hypokalemia is associated with flattenting of the T wave and the appearance of a U wave. When untreated, hypokalemia may lead to severe arrhythmias.
The fast ventricular depolarization and repolarization associated with hypercalcemia lead to a characteristic shortening of the QT interval. Hypocalcemia has the opposite effect, lengthening the QT interval.
Differentiating electrolyte disturbances from other diseases
Electrolyte disturbance must be differentiated from other causes of headache, altered mental status and seizures such as brain tumors and delirium trmemns.