Lecture Notes on Hypernatremia

These flashcards cover the key concepts, definitions, and physiological elements associated with hypernatremia as outlined in the lecture.

Hypernatremia

A hydro-electrolytic disorder characterized by a serum Na+ level greater than 145 meq/L, indicating a deficit of water rather than sodium.

Hypovolemic Hypernatremia

A type of hypernatremia where the loss of water exceeds the loss of sodium.

Euvolemic Hypernatremia

A type of hypernatremia characterized by pure water loss.

Hypervolemic Hypernatremia

A condition where the gain of sodium exceeds the gain of water.

Acute Hypernatremia

Hypernatremia that develops in less than 48 hours.

Chronic Hypernatremia

Hypernatremia that develops over more than 48 hours, posing a higher risk of cerebral edema upon correction.

Common Etiology of Hypernatremia

Typically involves a deficit of water, can be exacerbated by factors like aging, lack of access to water, or various renal and extrarenal water losses.

Renal Causes of Water Loss

Including diabetes and diuresis.

Extrarenal Causes of Water Loss

Including osmotic diarrhea, excessive sweating, hyperventilation, and burns.

Factors increasing risk of Hypernatremia

Elderly age, infants, neurological diseases, and hospitalization.

Role of Sodium (Na+)

The main solute of the extracellular fluid that influences plasma osmolarity, thirst regulation, and ADH secretion.

Steps in Pathophysiology of Hypernatremia

1. Water loss or sodium gain 2. Increased plasma osmolarity 3. Water movement from intracellular to extracellular fluid 4. Cellular dehydration, particularly neuronal 5. Activation of thirst and ADH secretion 6. Neurological damage if compensation fails.

Clinical Signs of Hypernatremia

Including dry skin, orthostatic hypotension, decreased turgor, and tachycardia.

Symptoms of Hypernatremia

Including confusion, lethargy, intense thirst, irritability, seizures, and coma.

Central Diabetes Insipidus

A condition where no ADH is produced.

Nefrogenic Diabetes Insipidus

Where V2 receptors do not respond to ADH.

Desmopressin

An analog of ADH used in certain treatments.