Patient will present with → neurological manifestations which include thirst, restlessness, lethargy, delirium, convulsions and coma, dry mouth, tachycardia, hypotension. Polyuria, polydipsia, and nocturia are the predominant manifestations of diabetes insipidus.
In hypernatremia the water content of the body fluid is deficient in relation to sodium content (serum sodium >145 mEq/L) and there is either too much salt or not enough water
Generally results from either inadequate fluid intake or excess water loss
- deficit of thirst
- hypotonic fluid loss
- urinary loss
- GI loss
- burns
- diuretic use
- osmotic diuresis (hyperglycemia)
- sodium excess
- diabetes insipidus
By definition, plasma sodium will be greater than 145 mEq/L (hypernatremia)
- Urine - sodium may be decreased if due to extrarenal losses, urine concentrated and diluted with diabete insipidus
- Hyperosmolar coma may be indicated by elevated serum glucose, and increased urine osmolality
Diabetes insipidus
- Neurogenic (central) is caused by deficient secretion of vasopressin (ADH - anti-piss-hormone) from the posterior pituitary
- Nephrogenic DI is caused by kidneys that are unresponsive to normal vasopressin levels - usually inherited X-linked or from lithium or renal disease
- Low urine sodium and polyuria usually indicate DI
- Urine osmolality of less than 250 despite hypernatremia, indicated Diabetes Insipidus
Patient should be treated on an ipatient basis
- Identify the underlying cause and treat accordingly - water may be administered PO which is the preferred route
- Hypovolemia should be treated first with isotonic saline or lactated ringers and the hypernatremia second, dialysis should be implemented if sodium is greater than 200 mEq/L
- Use caution during treatment as rapid correction of hyponatremia can cause pulmonary or cerebral edema, especially in patients with diabetes insipidus
![]() |
Hypernatremia is characterized by a serum sodium level above the normal range of 145 mEq/L. Hypernatremia is a increase in osmolarity of the extracellular fluid volume (ECF). This may be attributed to an actual sodium excess in the ECF like hyperaldosteronism or a relative sodium excess which is caused by a decrease of free water in the ECF like dehydration. High serum sodium levels causes a fluid shift from the intracellular fluid volume (ICF) to the ECF. This causes cellular shrinking. Hypernatremia should be assessed along with fluid balance as it often is associated with a fluid excess or deficit. |
Question 1 |
prolactin | |
oxytocin | |
insulin | |
growth hormone | |
antidiuretic hormone |
Question 2 |
- Sodium 162 mEq/L
- Potassium 3.8 mEq/L
- Chloride mEq/L
- Glucose 108 mEq/dL
- Creatinine 2.0 mEq/dL
- Urine sodium > 10 mEq/L
- Urine osmolality 428 mOsm/kg
Quarter normal (hypotonic) saline Hint: See C for explanation | |
Half-normal saline Hint: See C for explanation | |
Isotonic (normal) saline | |
Dextrose 5% in water Hint: See C for explanation | |
Lactated Ringer’s Hint: See C for explanation |
List |