Hyponatremia in the Older Adult

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Hyponatremia in the Older Adult|
168344|
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Vivienne Ellison 09039422|
8/6/2011|

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Hyponatremia in the older adult.

Management of defects in water homeostasis in the elderly is often difficult because of age related changes and diseases that are associated with impairment of water metabolism. The feeling of thirst is often impaired in the elderly (Kugler, 2000). Hyponatremia is a serum sodium concentration of less than the normal 137 mmol per litre (Farrell, 2007). This essay will explore why this condition happens to the older adult (over 65 years) and how to assess for it. The effects of this condition on the elderly will be explored. Problems that make it difficult for nursing assessment will be identified and recommendations will be made on how to overcome these barriers. Sodium is the most abundant electrolyte in the extracellular fluid. It controls water distribution through the body and a loss of sodium is usually accompanied by a loss of water (Farrell, 2007). The normal range for serum sodium level is 135 to 145 mEq/l (Bruck, 2005). Sodium in the body is determined by how much salt is in the diet and how the intestines absorb it (Bruck, 2005). Sodium helps to maintain normal blood pressure, supports the work of the nerves, muscles, and regulates the body’s fluid balance. When the sodium level in the body becomes too low, extra water enters the cells and causes them to swell. This can lead to swelling in the brain, which is especially dangerous because the brain is in a confined space and cannot expand without causing rising intracranial pressure. This condition is called Hyponatremia. There are three main ways based on the patient’s osmolality, in which the sodium may fall below 135. The first involves abnormal kidney function. Normal kidney function gets rid of excess water by secreting less anti diuretic hormone (ADH), which excretes excess water but reabsorbs sodium. When the kidney is not functioning normally, the sodium is not reabsorbed and the level decreases. The blood vessels contain more water and less sodium. By means of osmosis, the excess fluid moves from the extracellular area i.e. the blood vessel, into the intra cellular area, thus causing cerebral oedema and hypovolemia. This is called hypotonic hyponatremia. Both sodium and water levels go down in the extracellular area but more sodium than water is lost (Bruck, 2005). The causes may include renal impairment, vomiting, diarrhoea and excess wound drainage as in burns. Secondly, hypervolemic hyponatremia when both water and sodium levels increase in the extracellular area but the water gain is larger also causes hyponatremia (Bruck, 2005). The cause of this includes heart failure, nephrotic syndrome and fluid overloading with hypotonic IV fluids (Bruck, 2005). Lastly, isovolemic hyponatremia can be caused by hypothyroidism and renal failure. A key cause is a syndrome of inappropriate anti-diuretic hormone (SIADH) (Bruck, 2005). SIADH occurs with cancers, stroke, and pulmonary disorders such as COPD and with some oral antibiotics, central nervous system disorders also occurs with certain medications such as psychoactive drugs, diuretics and oral anti-diabetics (Bruck, 2005). The condition causes a large release of ADH, which in turn causes water retention. Treatment of the underlying cause such as cancer treatment will also treat the hyponatremia (Bruck, 2005). The older adult usually become unwell with hyponatremia due to age related causes that affects the way the body manages the balance of sodium and water. These include urinating less often, drinking too much water or too little water, less blood flow through the kidneys, severe vomiting and diarrhoea, liver failure, kidney failure and heart failure. Having high levels of anti-diuretic hormone (ADH) will also cause the body to retain water. An underactive thyroid and Addison’s disease also...
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