Sodium Disorders: Hyponatremia & Hypernatremia

These flashcards cover key definitions, concepts, and treatments related to sodium disorders, specifically focusing on hyponatremia and hypernatremia.

Sodium (Na*)

An extracellular cation with a normal value of 135-145 mmol/L.

Intra-Cellular Fluid (ICF)

Fluid contained within the cells.

Extra-Cellular Fluid (ECF)

Fluid outside of the cells, further divided into Intra-Vascular Fluid and Extra-Vascular Fluid.

Plasma Osmolarity

A measurement influenced by sodium, glucose, and blood urea nitrogen (BUN), normal range is 285 - 295mmol/L.

Hyponatremia

A condition characterized by serum sodium levels less than 135 mEq/L.

Hypovolemic Hyponatremia

Hyponatremia associated with sodium loss exceeding water loss.

Clinical Picture of Hypovolemic Hyponatremia

Signs include cold skin, hypotension, tachycardia, and oliguria.

Euvolemic Hyponatremia

Hyponatremia with normal sodium content but excess water.

Syndrome of Inappropriate ADH (SIADH)

A condition causing excess water retention leading to dilutional hyponatremia.

Hypervolemic Hyponatremia

Hyponatremia characterized by sodium and greater water retention.

Hypernatremia

A condition where serum sodium levels exceed 145 mEq/L, often due to water loss.

Symptoms of Hypernatremia

Symptoms include lethargy, confusion, seizures, and dehydration.

Osmotic Demyelination Syndrome (ODS)

A complication arising from rapid correction of hyponatremia.

Water Deficit Calculation

A method to determine fluid replacement needs given sodium levels, calculated using total body water (TBW).

Treatment of Hypovolemic Hyponatremia

Involves restoring volume with normal saline and treating the underlying cause.

Emergency Treatment for Severe Hyponatremia

Immediate IV administration of 3% hypertonic saline.

Key Diagnostic Step for Hyponatremia

Confirm hyponatremia by checking serum osmolality and urine sodium.

Chronic Hyponatremia Correction Rate

Safe correction should not exceed 4-6 mEq/L per 24 hours.

Diabetes Insipidus (DI) Type

A condition resulting in inadequate water retention; includes central and nephrogenic forms.

Renin-Angiotensin-Aldosterone System (RAAS)

Hormonal system regulating blood pressure and fluid balance.

Common Pitfalls in Sodium Management

Forgetting to check urine studies or correcting sodium too rapidly, which can lead to complications.