Water-Electrolyte Imbalance

Definition

An electrolyte disorder is an imbalance of certain ionized salts (i.e., bicarbonate, calcium, chloride, magnesium, phosphate, potassium, and sodium) in the blood.

Description

Electrolytes are ionized molecules found throughout the blood, tissues, and cells of the body. These molecules, which are either positive (cations) or negative (anions), conduct an electric current and help to balance pH and acid-base levels in the body. Electrolytes also facilitate the passage of fluid between and within cells through a process known as osmosis and play a part in regulating the function of the neuromuscular, endocrine, and excretory systems.

The serum electrolytes include:

• Sodium (Na). A positively charged electrolyte that helps to balance fluid levels in the body and facilitates neuromuscular functioning.
• Potassium (K). A main component of cellular fluid, this positive electrolyte helps to regulate neuromuscular function and osmotic pressure.
• Calcium (Ca). A cation, or positive electrolyte, that affects neuromuscular performance and contributes to skeletal growth and blood coagulation.
• Magnesium (Mg). Influences muscle contractions and intracellular activity. A cation.
• Chloride (CI). An anion, or negative electrolyte, that regulates blood pressure.
• Phosphate (HPO4). Negative electrolyte that impacts metabolism and regulates acid-base balance and calcium levels.
• Bicarbonate (HCO3). A negatively charged electrolyte that assists in the regulation of blood pH levels. Bicarbonate insufficiencies and elevations cause acid-base disorders (i.e., acidosis, alkalosis).

Medications, chronic diseases, and trauma (i.e., burns, fractures, etc.) may cause the concentration of certain electrolytes in the body to become too high (hyper-) or too low (hypo-). When this happens, an electrolyte imbalance, or disorder, results.

Sodium

HYPERNATREMIA. Sodium helps the kidneys to regulate the amount of water the body retains or excretes. Consequently, individuals with elevated serum sodium levels also suffer from a loss of fluids, or dehydration. Hypernatremia can be caused by inadequate water intake, excessive fluid loss (i.e., diabetes insipidus, kidney disease, severe burns, and prolonged vomiting or diarrhea), or sodium retention (caused by excessive sodium intake or aldosteronism). In addition, certain drugs, including loop diuretics, corticosteroids, and antihypertensive medications may cause elevated sodium levels.

Symptoms of hypernatremia include:

• thirst
• orthostatic hypotension
• dry mouth and mucous membranes
• dark, concentrated urine
• loss of elasticity in the skin
• irregular heartbeat (tachycardia)
• irritability
• fatigue
• lethargy
• heavy, labored breathing
• muscle twitching and/or seizures

HYPONATREMIA. Up to 1% of all hospitalized patients develop hyponatremia, making it one of the most common electrolyte disorders. Diuretics, certain psychoactive drugs (i.e., fluoxetine, sertraline, haloperidol), specific antipsychotics (lithium), vasopressin, chlorpropamide, the illicit drug "ecstasy", and other pharmaceuticals can cause decreased sodium levels, or hyponatremia. Low sodium levels may also be triggered by inadequate dietary intake of sodium, excessive perspiration, water intoxication, and impairment of adrenal gland or kidney function.

Symptoms of hyponatremia include:

• nausea, abdominal cramping, and/or vomiting
• headache
• edema (swelling)
• muscle weakness and/or tremor
• paralysis
• disorientation
• slowed breathing
• seizures
• coma

Content licensed from:

Author Info: Paula Ford-Martin, The Gale Group Inc., Gale, Detroit, Gale Encyclopedia of Medicine, 2002

This feature is for informational purposes only and should not be used to replace the care and information received from your healthcare provider. Please consult a healthcare professional with any health concerns you may have.