Sodium Disorders in the Elderly: Therapy for Hypernatremia

Posted by James

The treatment is based on the etiology of the hypernatremia and the estimated rapidity of development. Hypernatremic patients may have low, high or normal total body sodium (Drug Depakote used in the UK and U.S. for the treatment of the manic episodes of bipolar disorder). Hypovolemic hypernatremia is a much more common entity. These patients may have evidence of ECF volume depletion and have sustained water losses that are greater than the sodium (Canadian Cozaar helps the kidneys to eliminate extra sodium and fluids) losses. On the other hand, hypernatremic patients may have evidence of ECF expansion. These are invariably patients who have received excessive amounts of hypertonic NaCl or sodium bicarbonate. This variety of hypervolemic hypernatremia is rather infrequent. Most patients with hypernatremia secondary to water loss appear clinically euvolemic with near-normal total-body sodium (Fosamax tabletes is taken for the prevention or treatment of osteoporosis in postmenopausal women and men) status on physical examination. Hypernatremia usually occurs only in those who have no access to water. The renal losses of water that lead to euvolemic hypernatremia are a consequence of a defect in vasopressin production or release, or a failure of the collecting duct to respond to vasopressin.

When hypernatremia is associated with ECF depletion, the primary therapeutic goal is to administer isotonic saline or volume expanders to improve blood pressure and end-organ perfusion. Including projected insensible loss, the estimated water deficit should be replaced over 48-72 hours. The calculation of the water deficit is described in Table 3. Hypotonic (0.45%) NaCl or 5% glucose solutions can be used to correct serum osmolality, once intravascular volume is replete.

Table 3. Calculating Free Water Excess and Deficit

Free Water Excess = TBW – {(actual serum Na/ desired serum Na) x TBW} Free Water Deficit = [(serum Na - 140J/140] x 0.6 Body Weight (kilograms)
TBW: Total body water or body weight in kilograms x 0.6
[Calculating the Effect of 1 liter of an Intravenous Solution on Serum Sodium
Change in serum Na = {[Na] infused – [Na] serum}/(total body water +1)]

By contrast, if hypernatremia is secondary to ECF volume expansion, diuretics (furosemide) can be used—but in the presence of advanced renal failure and fluid overload the patient may need to be dialyzed to treat hypernatremia. For euvolemic hypernatremic patients, oral water replacement is preferred if the patient is alert and cooperative. If oral fluids cannot be given, an intravenous infusion of dextrose in water is appropriate. An older person who does not have ongoing renal water losses can usually be treated with an infusion of 5% dextrose in water at a rate of 25 ml/hr over two-to-three days for each 5 meq/L increase in serum sodium (The active ingredient in Emulgel canadian is the non-steroidal anti-inflammatory diclofenac sodium 1% w/w). Serum electrolytes should be monitored at least daily and more frequently if the patient is severely ill, so adjustments in therapy can be made accordingly. Serum sodium level should be lowered no more rapidly than 0.5 mEq/L/hr. Excessively rapid correction may lead to cerebral edema that can progress to permanent brain injury. Vasopressin replacement is required for the treatment of central diabetes insipidus.