Sodium Disorders in the Elderly: Hypernatremia

Posted by James

Hypernatremia is not uncommon at the extremes of age and is particularly prevalent among the elderly. A serum sodium (Canadian Coumadin is in a class of drugs known as anticoagulants) level of 150 meq/1 or greater should be considered clinically significant. The prevalence of hypernatremia in the elderly has been reported to be about 1% in both hospitalized patients and in residents of long-term care facilities. Since the percentage of body water falls with age, equal volumes of fluid loss in older individuals may represent more severe dehydration than in younger individuals. In healthy older men compared to younger controls, there are deficits in both the intensity and threshold of the thirst response, compared to younger controls. As mentioned earlier, the ability of the elderly to conserve water is also impaired. In the elderly, hypernatremia carries a high risk of morbidity and mortality ranging from 40-60%. Although mortality rate was highest in those with a rapid onset and those with serum sodium level >160 meq/L, a slow correction of serum sodium (Depakote drug affects chemicals in the body that may be involved in causing seizures) over a 72-hour period was reported to improve recovery of mental functions. Several common causes of hypernatremia in the elderly are shown (Table 4).

Table 4. Etiology of Hypernatremia in Elderly

Decreased Water Intake	Increased Water Loss	Increased Sodium Intake
Febrile illness	Diarrhea, fever	Prolonged saline infusion
Altered mental status	Osmotic diuresis (glycosuria, high protein tube feeding), lithium	Sodium bicarbonate therapy
Physical impairment	Diabetes insipidus, hypercalcemia, hypokalemia Chronic kidney disease

In many studies, dehydration is defined as a deficit in water (manifested as hypernatremia) and is commonly confused with hypovolemia, which is defined as a reduction in intravascular volume, independent of a change in the serum sodium (Florinef 0.1mg works by causing the kidneys to retain sodium in women after menopause). Dehydration associated with hypernatremia or hyponatremia is common in older individuals. In one study, dehy dration occurred in approximately 7% of hospitalizations among patients older than 65 years of age and was associated with significant morbidity.

Symptoms and Signs of Hypernatremia

Nonspecific lethargy and weakness are common. Obtundation, stupor, coma and seizures may accompany more severe hypernatremia. Clinical signs include decreased skin turgor, dry mouth, orthostatic hypotension, absent sweating and hemoconcentra-tion. In rare cases, hyperosmolality may lead to shrinkage of brain volume, capillary hemorrhage or spontaneous subtotal hematoma, resulting in permanent neurological deficits.