Sodium Disorders in the Elderly: Therapy for Hyponatremia

Posted by James

Treatment is dependent upon the pathogenesis of the hyponatremia and the severity of symptoms. Patients with hypotension should initially be treated with normal saline to replenish the intravascular volume. Patients should then be reassessed and if symptoms of hyponatremia persist following normalization of blood pressure, hypertonic saline should be given. Furthermore, the change in serum sodium (Drug Cozaar helps the kidneys to eliminate extra sodium and fluids) concentration in response to treatment needs to be followed closely. The rate of rise of serum sodium should not exceed 0.3-0.4 mmol/hr (7-10 meq/24 hours), since correction at a rate greater than 0.5 mmol/hr has been associated with severe neurologic complications, including osmotic demyelination syndrome. Care must also be taken not to induce fluid overload and pulmonary vascular congestion. The administration of normal saline at 75 ml/hr should raise serum sodium (Fosamax medication is taken for the prevention or treatment of osteoporosis in postmenopausal women and men) by approximately 0.3-0.4 mmol/hr. If there is any concern of heart disease, a lesser rate of about 50 ml/hr is advisable. The serum sodium level should be repeated as necessary, regulated as dictated by the clinical situation with adjustment of the fluid rate as required. In sodium depletion, the quantity of sodium required to increase the serum sodium concentration by a given amount can be estimated more precisely by multiplying the desired change in serum sodium by the total body water (e.g., 8 mmol/liter change in a 60-kg person over 24 hours is 8 mmol/liter x 36 liters = 288 mmol = approximately 1.9 liter normal saline or 560 ml 3% NaCl). It should be noted that symptoms related to hyponatremia occur disproportionately throughout the population. Both aging and male gender appear to confer protection against the development of hyponatremia-associated seizures, permanent brain damage and/or mortality, although the reasons) for this is unclear. In asymptomatic patients with no evidence of volume depletion, as in SIADH, correction of the underlying problem and restriction of free water intake to 1 liter per day is usually sufficient to normalize the serum sodium (The active ingredient in Emulgel 50gm is the non-steroidal anti-inflammatory diclofenac sodium 1% w/w).

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 (Medication Avapro works by decreasing certain chemicals in the body, which cause blood vessels to narrow and sodium)
Change in serum Na = {[Na] infused – [Na] serum}/(total body water +1)]

Chronic hyponatremia in postmenopausal women is not uncommon and is often viewed as a benign condition. Recommended therapy for asymptomatic patients is usually fluid restriction. A nonrandomized prospective multicenter study found that chronic symptomatic hyponatremia in postmenopausal women can be associated with major morbidity and mortality, and therapy with IV sodium (Cozaar tabletes works by helps the kidneys to eliminate extra sodium and fluids) chloride was associated with better outcomes than fluid restriction. In patients with clinical evidence of excess extracellular fluid volume, the free water excess can be estimated using the formula shown in Table 3. Bed rest, water restriction and/or increasing water excretion with furosemide (20-40 mg intravenously twice a day), which induces hypotonic urine that results in a negative free water balance, are effective in most patients. In cases of SIADH refractory to free water restriction (i.e., malignancies, other), demeclocycline 300 mg orally four times a day for up to 10 days can be used to blunt the renal tubular response to circulating ADH and stimulate water diuresis. Although lithium was used as a treatment in the past, as it also induces a renal tubular resistance to ADH, the risk of clinical side effects is too great to recommend it as a standard therapeutic option.