Hyponatremia In Older Adults

| Hyponatremia in the Older Adult | 168344 | | 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 contribute to hyponatremia. Furthermore, along with these conditions the older adult will need to take certain medications such as diuretics, antidepressants and pain medications, which can cause some form of hyponatremia. Fluid deficiency studies comparing younger adults with older people show that despite physiological needs, older people do not consume adequate amounts of fluids to maintain electrolyte concentrations (Ahmed, 2010). Fluid intake in the older adult can be also affected by cognitive impairment (Ahmed, 2010). The signs and symptoms of hyponatremia vary from person to person but the sodium will be below 135mml/l. The main symptoms are largely neurological including headaches, irritability and patients becoming disorientated, with muscle weakness and twitching and a changing level of consciousness (Marieb, 2007). Poor skin turgor and dry mucous membrane, a raised blood pressure, rapid bounding pulse and weight gain all contribute to symptoms of hyponatremia (Farrell, 2007). To treat the condition the underlying cause must be treated. The difficulties are that there are many and varied causes of this condition. To identify the cause will require the medical professional to start by getting a good history from the patient. Enquire about current medications including the use of over the counter medications such as laxatives. The history must include any vomiting or diarrhoea, which could cause hypovolemia and hyponatremia. It is sometimes difficult to get a good history because of the symptoms of confusion and irritability. Furthermore, it is difficult to tell if this is the patient’s normal state. The elderly may have a diagnosis of Alzheimer’s disease or dementia, which may mask the symptoms of hyponatremia. It is helpful to get some background history from family or caregivers that can identify the patient’s normal state. Laboratory tests should include checking serum osmolity and urine osmolality to see if “the urine is appropriately diluted (L 100 mOs m/kg) or inappropriately concentrated (more than 100 mOsm/kg),” (Viadya, Ho, & Freda, pg.716, 2010). If they are the cause of hyponatremia then it will be either excessive fluid intake or low salt intake. With fluid restriction and/or increased sodium intake, the serum sodium concentration usually returns to normal (Viadya, Ho, & Freda, 2010). Assessment for underlying causes such as hyponatremia induced by thiazide diuretics, and other drugs such as selective serotonin reuptake inhibitors (SSRI) which potentiate anti-diuretic hormone action is needed (Viadya, et al, 2010). Stopping these diuretics and replenishing the depleted fluid volume will rapidly reverse the hyponatremia. The Serum sodium levels need to be measured and reviewed regularly. A recent study showed that those patients without serious signs or symptoms or are asymptomatic will nevertheless still benefit from some therapy to raise the serum sodium as these people are more likely to present to hospital with falls compared with aged-matched controls (Viadya, et al, 2010). This result was thought to be because they had gait and attention impairment. Furthermore, these falls are associated with a high risk of bone fractures (Viadya, et al, 2010). Other conditions that predispose the patient to water retention such as congestive heart failure, hepatic failure, or renal failure, conditions that particularly affect the elderly, should be treated to result in water extraction and improve the serum sodium level (Viadya, et al, 2010). Loop diuretics can be given but thiazide diuretics should be avoided as they impair urinary dilution (Bruck, 2005). In patients without hypervolemia, salt intake can be increased to enhance water removal. For the elderly whose nutritional intake is limited for example an elderly patient existing on milk and cereal , a high-protein food or supplements should be encouraged so that enough salt is obtainable to continue to excrete water (Viadya, et al, 2010). Serum sodium levels need to be closely observed to avoid overcorrection. Hypertonic saline should be avoided because it can cause an overcorrection, which can cause serious neurologic injury (Viadya, et al, 2010). During a recent study comparing patients who were admitted with hyponatremia and those who developed hospital acquired hyponatremia linked to treatment related factors, it was found that the hospital-acquired group had inadequate or delayed management of the condition (Hoorn, Lindemans, & Ziets, 2006). Some of the reasons for this result were treatment related factors such as being treated with thiazide diuretics. However, it was delayed management, which allowed a further decrease in plasma sodium, that put these patients in danger (Hoorn, et al, 2006). The serum sodium level was less often documented and one possible conclusion is that it was not checked as often as was necessary. Nurses can play a large part in preventing a patient from suffering a decline in condition and the following nursing recommendations for getting the best patient outcome are made. Frequent monitoring of lab results is advised in order to note deteriorating plasma Na levels and urine specific gravity and serum osmolality (Bruck, 2005). Nurses should discuss the results with the treating doctors and document results. Encourage good nutrition with a high protein diet and educate the patient on dietary sodium. A nursing referral to the dietician will help the patient further understand how sodium can be included in the diet. Keep accurate fluid balance charts of input and output, and follow fluid restrictions as per the doctor’s instructions, because lowering water intake to equal the low volume of urine caused by the increase in ADH may be all that is needed to correct the balance. A fluid restriction should include putting up signs about the restrictions so that family, the next shift, and kitchen staff are all aware of the restriction, as the patient may not be able to understand and follow it. Include in documentation if the patient is compliant with the restrictions and changes in the diet. Weigh the patient daily to assess if diuretic treatment or fluid restriction is effective. Review the drug chart noting thiazide diuretics, SSRI antidepressants, sedatives such as morphine, and anti-diabetics, which can cause hyponatremia. Discuss with the doctor and the pharmacist to see if there would be a more appropriate drug for the patient. Nurses must be aware that hypotonic IV fluids may contribute to hyponatremia developing, so frequent monitoring of plasma Na results is important. Assess skin turgor for signs of dehydration. Check neurological status regularly and report any deterioration in levels of consciousness, looking for seizures, coma or muscle twitching and fatigue (Bruck, 2005). Safety of the patient is vital. Keeping the patient safe whilst undergoing treatment can be challenging as the patient may have altered thought processes, which make them confused and agitated. Arrange for a watch to mind the patient if they are very confused. Keep the patient safe from seizures by padding side rails and keep suction equipment and artificial airway handy (Bruck, 2005). In conclusion, hyponatremia is a common condition in the elderly because they often have impaired ability to regulate fluid input and output.
This may be due to disease process or because regulatory function is impaired. The signs and symptoms of hyponatremia can be confused with other conditions however; blood test results will clearly show a low sodium level. There are many treatment stratergies, which aim to treat the underlying causes. Hyponatremia is a condition that requires treatment to correct cerebral oedema. Even those who are asymptomatic will benefit from treatment as they are at greater risk of falls and injury. Hospitals have been shown to be good at treating initial presentations of hyponatremia but not as good at identifying developing cases of hyponatremia. Nurses can become more aware of this condition by regular checking of laboratory results and following through with fluid restrictions as directed, daily weighs, and good fluid balance documentation. As patients in a confused state are not always able to communicate well, nurses must check electrolyte balances to rule out this cause for confusion or lower level of consciousness. Nurses must continue to check for possible side effects of their patients current
medications.

Reference list
Ahmed, T. &. (2010). Assessment and management of nutrition in older people and its importance to health. Clinical Interventions in Aging, 207-216.
Bruck, L. L. (2005). Fluids & Electrolytes Made Incredibly Easy. Philadelphia: Lippincott Williams & Wilkins.
Farrell, M. (2007). Smeltzer & Bare's Textbook of Medical-Surgical Nursing. Broadway NSW: Lippincott Williams & Wilkins.
Hoorn, E., Lindemans, J., & Ziets, R. (2006). Development of severe hyponatremia in hospitalised patients: treatment related risk factors and inadequate management. Nephrology Dialysis Transplantation, 70-76.
Kugler, J. &. (2000). Hyponatremia and hypernatremia in the elderly. American Family Physician, 15; 61(12):3623-30.
Marieb, E. N. (2007). Human Anatomy & Physiology. Seventh ed. San Francisco: Pearson Benjamin Cummings.
Viadya, C., Ho, W., & Freda, B. (2010). Management of hyponatremia: Providing treatment and avoiding harm. Cleveland Clinic Journal of Medicine, 715-726.