Sodium Imbalances

What is the most common cause of hypernatremia?

water deficiency and not sodium excess

What physiological effect does hypernatremia have on cells?

causes cellular dehydration as water shifts from cells to ECF fluid due to hyperosmolarity

what are common causes of water loss leading to hypernatremia?

• Inadequate water intake

• Diabetes insipidus (central or nephrogenic)

• Osmotic diuresis (e.g., hyperglycemia)

• Insensible water loss (fever, heatstroke)

what are examples of sodium gain that can cause hypernatremia?

• hypertonic saline or sodium bicarbonate

• sodium-containing medications

• seawater ingestion

• primary aldosteronism

Why is hypernatremia rare in alert individuals?

Because thirst is the body’s primary defense and they can access and drink water

What are neurological signs of hypernatremia due to brain cell dehydration?

drowsiness

restlessness

confusion

lethargy

seizures

Coma

what cardiovascular manifestations may occur if hypernatremia is accompanied by ECF volume deficit?

• postural hypotension

• tachycardia

• weakness

what determines the management of hypernatremia?

the underlying cause and the patient’s volume status

what is the treatment for hypernatremia caused by primary water deficit?

fluid replacement with oral fluids or IV isotonic fluids like 0.9% sodium chloride

what is the treatment caused by sodium excess?

• dilute high sodium levels with sodium-free IV fluids (5% dextrose in water)

• promote sodium excretion with diuretics

• restrict dietary sodium

what precautions should be taken for a hypernatremic patient with altered LOC and seizures

initiate seizure precautions:

• 4 padded side rails up

• padding

• suction

• oxygen

what labs should be monitored during hypernatremia treatment?

• serum sodium levels

• serum osmolality

• patient’s response to therapy

how fast should serum sodium levels be reduced in hypernatremia?

no more than 8-15 mEq/L in 8 hours to prevent cerebral edema and neurological complications, especially if hypernatremia developed gradually

What are common causes of hypernatremia from excess sodium intake?

• hypertonic enteral nutrition without water

• hypertonic NaCl, excess isotonic NaCl, IV sodium bicarbonate

• Saltwater near-drowning

what are causes of hypernatremia due to inadequate water intake?

unconscious or cognitively impaired individuals

what are causes of hypernatremia from excess water loss?

• diarrhea

• insensible loss

• osmotic diuretics

what diseases can lead to hypernatremia?

• Cushing syndrome

• diabetes insipidus

• primary hyperaldosteronism

• uncontrolled diabetes

What are hypernatremia manifestations with decreased extracellular fluid volume?

• agitation, restlessness, seizures, coma

• intense thirst, dry swollen tongue, sticky mucous membranes

• postural hypotension, weight loss, increase pulse

what are hypernatremia manifestations with normal or increased extracellular fluid volume?

• restlessness, twitching, seizures, coma

• edema, flushed skin, intense thirst

• weight gain, increased BP, increased central venous pressure

what are causes hyponatremia from sodium loss?

• vomiting, diarrhea, NG suctioning

• diuretics, adrenal isufficiency

• burns, wound drainage

what are causes of hyponatremia from inadequate sodium intake?

• fasting diets

what are causes of hyponatremia from excess water gain?

• excess hypotonic IV fluids

• primary polydipsia

What diseases can cause hyponatremia?

• cirrhosis

• heart failure

• SIADH

• Primary hypoaldosteronism

what are hyponatremia manifestations with decreased extracellular fluid volume

• irritability, confusion, tremors, seizures, coma

• postural hypotension, dry mucosa, increase pulse

• cold, clammy skin

what are hyponatremia manifestations with normal or increased extracellular fluid volume?

• apathy, headache, muscle spasms, seizures, coma

• nausea, vomiting, diarrhea, cramps

• weight gain, increase BP, increase central venous pressure

What is hyponatremia?

it is a low serum sodium level, typically due to sodium loss, water excess, or both

what is dilutional hyponatremia?

a condition where there is excess water in relation to sodium, causing sodium levels to appear low due to dilution

What happens to body fluids in hyponatremia due to hypoosmolality?

water shifts from ECF into cells, causing cellular edema

what are common causes of sodium loss that leads to hyponatremia?

• draining wounds

• diarrhea

• vomiting

• primary adrenal insufficiency

what causes hyponatremia from water excess?

• inappropriate use of sodium-free or hypotonic IV fluids

• post-op or trauma patients

• renal failure patients

• psychiatric disorders causing excess water intake

How does SIADH cause hyponatremia?

SIADH causes abnormal water retention, leading to dilution hyponatremia

what causes the clinical manifestations of hyponatremia?

cellular swelling, especially in the central nervous system

what are mild CNS symptoms of hyponatremia?

• confusion

• vomiting

• seizures

• coma

what can result from rapidly developing, severe hyponatremia?

irreversible neurological damage from death from brain herniation

How is hyponatremia due to fluid loss treated?

replace fluids with isotonic sodium-containing solutions, encourage oral intake, and withhold diuretics

what is the treatment for mild hyponatremia caused by water excess?

fluid restriction may be the only treatment needed

what medications may be used to treat hyponatremia caused by water excess?

loop diuretics and demeclocycline

what is used to treat serious or acute hyponatremia?

small amounts of 3% hypertonic saline solution

what are vasopressor receptor antagonists used for in hyponatremia?

they block ADH and are used in patients with SIADH or fluid overload who cannot tolerate fluid restriction

Name two vasopressor receptor antagonists and their uses

• Conivaptan (Vaprisol): IV for hospitalized patients

• Tolvaptan (Samsca): Oral for heart failure or SIADH

What is the recommended rate of serum sodium correction in hyponatremia?

• No more than 10–12 mEq/L in 24 hours

• No more than 18 mEq/L in 48 hours

What can happen with rapid correction of hyponatremia?

Osmotic demyelination syndrome—permanent damage to brain nerve cells.

What monitoring and safety measures are critical in hyponatremia management?

• Monitor serum sodium and urine output

• May require urinary catheter

• Implement seizure precautions for altered LOC or seizures