Sodium - Book

This Electrolyte is considered the ‘Chief Electrolyte’ of extracellular fluid.

Sodium

Is sodium a Cation or Anion?

Cation

What are the key functions of sodium (Na⁺) in the body?

• Regulates extracellular fluid volume I.e. water shifts with Na⁺ (Loss or Gain)

• Affects serum osmolality

• Supports muscle contraction and nerve signaling

• Regulates acid–base balance (as sodium bicarbonate)

How does sodium normally enter and leave the body?

• Enters via GI tract (dietary salt, processed foods, preservatives)

• Lost through GI tract, kidneys, and skin

How is sodium regulated in the body?

• Transported out of cells by sodium–potassium pump

• Controlled by renin–angiotensin–aldosterone system

• Eliminated or reabsorbed by kidneys

• Influenced by salt and water intake

How can sodium be lost?

• Vomiting

• Diarrhea

• Fistulas

• Sweating

• Diuretic use

What does a decrease in sodium in the ECF cause?

It causes fluid to shift by osmosis from the less concentrated ECF to the ICF space.

What can the shift of fluid from ECF to the ICF space cause?

• Swelling of the cells

• Confusion

• Hypotension

• Edema

• Muscle cramps

• Weakness

• Dry skin

Severe Hyponatremia is manifested by Signs of what?

• Increasing intracranial pressure

• Lethargy

• Muscle twitching

• Hyperreflexia

• Coma

• Seizures

• Death

What can lead to excess sodium levels in the body (hypernatremia)?

• Fluid deprivation or inadequate fluid intake

• Inability to perceive, respond to, or communicate thirst (e.g., in elderly or neurologically impaired patients)

• Diarrhea, causing water loss

• Excess insensible water loss, such as

  • Hyperventilation

  • Burns

• Rapid or excessive administration of sodium-containing IV solutions

Fluids move from the cells in hypernatremia because of what?

Increased extracellular osmotic pressure

What cells are especially effected by hypernatremia?

The cells of the central nervous system

Signs of neurologic impairment related to hypernatremia?

• Restlessness

• Agitation

• Weakness

• Disorientation

• Delusions

• Hallucinations

• Seizures

• Permanent brain damage, especially in infants and children