Sodium Imbalance

What is Sodium Imbalance ?

Sodium is the major cation (90%) in extracellular fluid (ECF). It's the main factor responsible for ECF concentration. Increases or decreases in ECF sodium concentrations greatly affect ECF volume and distribution. Sodium controls the distribution of water throughout the body and regulates ECF volume. It also plays an important role in the transmission of nerve impulses and muscle contraction.

Hyponatremia is an excess of body water relative to sodium; it isn't synonymous with sodium depletion. Sodium loss is just one state in which hyponatremia can occur. Hypernatremia is a deficit of body water relative to sodium. Thirst seems to be the major defense mechanism against hypernatremia.

Causes of Sodium Imbalance

• Prolonged loss of body fluids from vomiting or diarrhoea;
• Addison's disease;
• Congestive heart failure;
• Prolonged, excessive drinking of water;
• Excessive exercise and sweating;
• Some cancers of the adrenal glands;
• Infections with high fever.

High sodium levels "hypernatraemia" are caused by:

• Inability to drink water.
• kidney disease
• corticosteroid medicines, such as prednisone
• excessive intake of salty foods

Signs & Symptoms of Sodium Imbalance

Many of the clinical features of hyponatremia relate to brain swelling and cerebral edema. The development and severity of symptoms is also related not only to the degree of hyponatremia, but also the rate at which the sodium concentration in the body is changing. Common signs and symptoms of salt imbalance include:

• weakness, often the first symptom of hyponatremia
• changes in heart rate, heartbeat, and blood pressure
• lack of coordination
• irritability
• tissue swelling
• coma
• confusion
• restlessness and agitation
• retaining fluid in the body
• eliminating large amounts of urine

Diagnostic Tests

Serum sodium levels are less than 135 mEq/L with hyponatremia and greater than 145 mEq/L with hypernatremia.

Treatment

When possible, patients with sodium deficits receive oral sodium supplementation. Therapy for mild hyponatremia associated with hypervolemia usually consists of restricted water intake. If fluid restriction alone fails to normalize serum sodium levels, demeclocycline or lithium, which blocks ADH action in the renal tubules, can be used to promote water excretiop.

In extremely rare instances of severe symptomatic hyponatremia, when serum sodium levels fall below 110 mEq/L, treatment may include infusion of 3% or 5% sodium chloride solution.

If indicated, treatment must include correction of the underlying disorder; for example, hormonal therapy may be needed to treat endocrine disorders.

Primary treatment for hypernatremia associated with water deficit includes slow, oral replacement of the water deficit to stop the water loss. If the patient can't tolerate oral replacement, treatment requires I.V. administration of salt-free solutions (such as dextrose in water) to return serum sodium levels to normal, followed by infusion of half-normal saline solution to prevent hyponatremia.

ALERT: Hypernatremia must be corrected slowIy, over about 2 days, to avoid shifting water into brain cells, resulting in cerebral edema. Some clinicians recommend infusion of a hypotonic solution, such as 0.3% sodium chloride, to permit a more gradual lowering of serum sodium levels. reducing the risk of cerebral edema.

Prevention Tips

A person can take these actions to help prevent salt imbalance:

• A person avoid salty foods, salt tablets, or salty liquids, such as sports drinks
• drink plenty of water when taking diuretics
• keep follow-up appointments with the doctor for chronic disease treatment