Age-Related Changes in Health   3  

Constance M. Smith and Valerie T. Cotter

OVERVIEW

The process of normal aging, independent of disease, is accompanied by a myriad of changes in body systems. As evidenced by longitudinal studies, such as the Baltimore Longitudinal Study of Aging (2015), modifications occur in both structure and function of organs and are most pronounced at an advanced age of 85 years or older (Hall, 2002). Many of these alterations are characterized by a decline in physiological reserve. Although baseline function is preserved, organ systems become progressively less capable of maintaining homeostasis in the face of stresses imposed by the environment, disease, or medical therapies (Miller, 2009). Age-related changes are strongly impacted by genetics (Harada, Natelson Love, & Triebel, 2013), as well as by long-term lifestyle factors, including physical activity, diet, alcohol consumption, and tobacco use (Kitzman & Taffet, 2009). Furthermore, great heterogeneity occurs among older adults; clinical manifestations of aging can range from stability to significant decline in function of specific organ systems (Beck, 1998).

The clinical implications of these age-related alterations are important in nursing assessment and care of the older adult for several reasons (Smith & Cotter, 2012). First, changes associated with normal aging must be differentiated from pathological processes in order to develop appropriate interventions (Gallagher, O’Mahony, & Quigley, 2008). Manifestations of aging can also adversely impact the health and functional capability of older adults and require therapeutic strategies to correct (Matsumura & Ambrose, 2006). Age-associated changes predispose older persons to selected diseases (Kitzman & Taffet, 2009). Thus, nurses’ understanding of these risks can serve to develop more effective approaches to assessment and care. Finally, aging and illness may interact reciprocally, resulting in altered presentation of illness, response to treatment, and outcomes (Hall, 2002).

This chapter describes age-dependent changes for several body systems. Clinical implications of these alterations, including associated disease risks, are then discussed, followed by nursing assessment and care strategies related to these changes.

CARDIOVASCULAR SYSTEM

Cardiac reserve declines in normal aging. This alteration does not affect cardiac function at rest and resting heart rate, ejection fraction, and cardiac output remain virtually unchanged with age. However, under physiological stress, the ability of the older adult’s heart to increase both rate and cardiac output, in response to increased cardiac demand, such as physical activity or infection, is compromised (Lakatta, 2000). Such diminished functional reserve results in reduced exercise tolerance, fatigue, shortness of breath, slow recovery from tachycardia (Watters, 2002), and intolerance of volume depletion (Mick & Ackerman, 2004). Furthermore, because of the decreased maximal attainable heart rate with aging, a heart rate greater than 90 beats per minute (bpm) in an older adult indicates significant physiological stress (Kitzman & Taffet, 2009).

Age-dependent changes in both the vasculature and the heart contribute to the impairment in cardiac reserve. An increase in the wall thickness and stiffness of the aorta and carotid arteries results in diminished vessel compliance and greater systemic vascular resistance (Thomas & Rich, 2007). Elevated systolic blood pressure (BP) with constant diastolic pressure follows, increasing the risk of isolated systolic hypertension and widened pulse pressure (AlGhatrif & Lakatta, 2015). Strong arterial pulses, diminished peripheral pulses, and increased potential for inflamed varicosities commonly occur with age. Reductions in capillary density restrict blood flow in the extremities, producing cool skin (Mick & Ackerman, 2004).

As an adaptive measure to increased workload against noncompliant arteries, the left ventricle and atrium hypertrophy and become rigid. The ensuing impairment in relaxation of the left ventricle during diastole places greater dependence on atrial contractions to achieve left ventricular filling (Lakatta, 2000; Shah et al., 2008). In addition, sympathetic response in the heart is blunted because of diminished beta-adrenergic sensitivity, resulting in decreased myocardial contractility (Thomas & Rich, 2007).

Additional age-related changes include sclerosis of atrial and mitral valves, which impairs their tight closure and increases the risk of dysfunction. The ensuing leaky heart valves may result in aortic regurgitation or mitral stenosis, which present on examination as heart murmurs (Kitzman & Taffet, 2009). Loss of pacemaker and conduction cells contributes to changes in the resting electrocardiogram (EKG) of older adults. Isolated premature atrial and ventricular complexes are common arrhythmias, and the risk of atrial fibrillation is increased (Thomas & Rich, 2007). Because of atrial contractions in diastole, S₄ frequently develops as an extra heart sound, occurring immediately before the normal S₁ and S₂ (Lakatta, 2000; Shah et al., 2008).

Baroreceptor function, which regulates BP, is impaired with age, particularly with change in position. Postural hypotension with orthostatic symptoms may follow, especially after prolonged bed rest, dehydration, or cardiovascular drug use, and can cause dizziness and the potential for falls (Mukai & Lipsitz, 2002).

Cardiac assessment of an older adult includes performing an EKG and monitoring heart rate (40–100 bpm within normal limits), rhythm (noting whether it is regular or irregular), heart sounds (S₁, S₂, and extra heart sounds S₃ and S₄), and murmurs (noting location where loudest). The apical impulse is displaced laterally. In palpation of the carotid arteries, asymmetric volumes and decreased pulsations may indicate aortic stenosis and impaired left cardiac output, respectively. Auscultation of a bruit potentially suggests occlusive arterial disease. Peripheral pulses should be assessed bilaterally at a minimum of one pulse point in each extremity. Assessment may reveal asymmetry in pulse volume suggesting insufficiency in arterial circulation (Docherty, 2002). The nurse should examine lower extremities for varicose veins and note dilation or swelling. In addition, dyspnea with exertion and exercise intolerance are critical to note (Mahler, Fierro-Carrion, & Baird, 2003).

BP should be measured at least twice (Kestel, 2005) on the older adult and performed in a comfortably seated position with back supported and feet flat on the floor. The BP should then be repeated after 5 minutes of rest. Measurements in both supine and standing positions evaluate postural hypotension (Mukai & Lipsitz, 2002).

Nursing care strategies include referrals for older adults who have irregularities of heart rhythm and decreased or asymmetric peripheral pulses. The risk of postural hypotension emphasizes the need for safety precautions (Mukai & Lipsitz, 2002) to prevent falls. These include avoiding prolonged recumbency or motionless standing and encouraging the older adult to rise slowly from lying or sitting positions and wait for 1 to 2 minutes after a position change to stand or transfer. Overt signs of hypotension, such as a change in sensorium or mental status, dizziness, or orthostasis, should be monitored, and fall-prevention strategies should be instituted. For optimal cardiac functioning, sufficient fluid intake is advised to ensure adequate hydration and prevent hypovolemia (Docherty, 2002; Watters, 2002).

Older adults should be encouraged to adopt lifestyle practices for cardiovascular fitness with the aim of a healthy body weight (body mass index [BMI] 18.5–24.9 kg/m²; American Heart Association Nutrition Committee; Lichtenstein et al., 2006) and normal BP (James et al., 2014). These practices involve eating a healthful diet (Knoops et al., 2004), physical activity appropriate for age and health status (Netz, Wu, Becker, & Tenenbaum, 2005), and elimination of the use of and exposure to tobacco products (U.S. Department of Health and Human Services [USDHHS], 2014).

PULMONARY SYSTEM

Respiratory function slowly and progressively deteriorates with age. This decline in ventilatory capacity seldom affects breathing during rest or customary limited physical activity in healthy older adults (Zeleznik, 2003); however, with greater than usual exertional demands, pulmonary reserve against hypoxia is readily exhausted and dyspnea occurs (Imperato & Sanchez, 2006).

Several age-dependent anatomic and physiologic changes combine to impair the functional reserve of the pulmonary system. Respiratory muscle strength and endurance deteriorate to restrict maximal ventilatory capacity (Buchman et al., 2008). Secondary to calcification of rib-cage cartilage, the chest wall becomes rigid (Imperato & Sanchez, 2006), limiting thoracic compliance. Loss of elastic fibers reduces recoil of small airways, which can collapse and cause air trapping, particularly in dependent portions of the lung. Decreases in alveolar surface area, vascularization, and surfactant production adversely affect gaseous exchange (Zeleznik, 2003).

Additional clinical consequences of aging include an increased anteroposterior chest diameter caused by skeletal changes. An elevated respiratory rate of 12 to 24 breaths per minute accompanies reduced tidal volume for rapid, shallow breathing. Limited diaphragmatic excursion and chest/lung expansion can result in less effective inspiration and expiration (Buchman et al., 2008; Mick & Ackerman, 2004). Because of decreased cough reflex effectiveness and deep-breathing capacity, mucus and foreign matter clearance is restricted, predisposing to aspiration, infection, and bronchospasm (Watters, 2002). Furthermore, elevating the risk of infection is a decline in ciliary and macrophage activities and drying of the mucosal membranes with more difficult mucus excretion (Htwe, Mushtaq, Robinson, Rosher, & Khardori, 2007). With the loss of elastic recoil comes the potential for atelectasis. Because of reduced respiratory center sensitivity, ventilatory responses to hypoxia and hypercapnia are blunted (Imperato & Sanchez, 2006), putting the older adult at risk of developing respiratory distress with illness or administration of narcotics (Zeleznik, 2003).

The modifications in ventilatory capacity with age are reflected in changes in pulmonary function tests measuring lung volumes, flow rates, diffusing capacity, and gas exchange. Whereas the total lung capacity remains constant, the vital capacity is reduced and the residual volume is increased. Reductions in all measures of expiratory flow (forced expiratory volume in 1 second [FEV₁], forced vital capacity [FVC], FEV₁/FVC, peak expiratory flow rate [PEFR]) quantify a decline in useful air movement (Imperato & Sanchez, 2006). Because of impaired alveolar function, diffusing capacity of the lung for carbon monoxide (DLCO) declines as does pulmonary arterial oxygen tension (PaO₂), indicating impaired oxygen exchange; however, arterial pH and partial pressure of arterial carbon dioxide (PaCO₂) remain constant (Enright, 2009). Reductions in arterial oxygen saturation and cardiac output restrict the amount of oxygen available for use by tissues, particularly in the supine position, although arterial blood gas seldom limits exercise in healthy subjects (Zeleznik, 2003).

Respiratory assessment includes determination of breathing rate, rhythm, regularity, volume (hyperventilation/hypoventilation), depth (shallow, deep; Docherty, 2002), and effort (dyspnea; Mahler et al., 2003). Auscultation of breath sounds throughout the lung fields may reveal decreased air exchange at the lung bases (Mick & Ackerman, 2004). Thorax and symmetry of chest expansion should be inspected. A history of respiratory disease (tuberculosis, asthma), tobacco use (expressed as pack years), and extended exposure to environmental irritants through work or avocation are contributory (Imperato & Sanchez, 2006).

Subjective assessment of cough includes questions on quality (productive/nonproductive), sputum characteristics (note hemoptysis; purulence indicating possible infection), and frequency (during eating or drinking, suggesting dysphagia and aspiration; Smith & Connolly, 2003).

Secretions and decreased breathing rate during sedation can reduce ventilation and oxygenation (Watters, 2002). Oxygen saturation can be followed through arterial blood gases and pulse oximetry (Zeleznik, 2003), whereas breathing rate (greater than 24 respirations per minute), accessory muscle use, and skin color (cyanosis, pallor) should also be monitored (Docherty, 2002). The inability to expectorate secretions, the appearance of dyspnea, and decreased saturation of oxygen (SaO₂) levels suggest the need for suctioning to clear airways (Smith & Connolly, 2003). Optimal positioning to facilitate respiration should be regularly monitored with use of upright positions (Fowler’s or orthopneic position) recommended (Docherty, 2002). Pain assessment may be necessary to allow ambulation and deep breathing (Mick & Ackerman, 2004). See Atypical Presentation of Disease section for assessment of pneumonia, tuberculosis, and influenza.

Nursing care strategies useful in facilitating respiration and maintaining patent airways in the older adult include positioning to allow maximum chest expansion through the use of semi- or high-Fowler’s or orthopneic position (Docherty, 2002). Additionally, frequent repositioning in bed or encouraging ambulation, if mobility permits, is advised (Watters, 2002). Analgesics may be necessary for ambulation and deep breathing (Mick & Ackerman, 2004).

Hydration is maintained through fluid intake (6–8 oz/d) and air humidification, which prevent desiccation of mucous membranes and loosen secretions to facilitate expectoration (Suhayda & Walton, 2002). Suctioning may be necessary to clear airways of secretions (Smith & Connolly, 2003) and oxygen should be provided as needed (Docherty, 2002). Incentive spirometry, with the use of sustained maximal inspiration (SMIs) devices, can improve pulmonary ventilation, mainly inhalation, as well as loosen respiratory secretions, particularly in older adults who are unable to ambulate or are declining in function (Dunn, 2004).

Deep-breathing exercises, such as abdominal (diaphragmatic) and pursed-lip breathing, in addition to controlled and huff coughing, can further facilitate respiratory function. Techniques for healthy breathing, including sitting and standing erect, nose breathing (Dunn, 2004), and regular exercise (Netz et al., 2005) should be promoted. Education on eliminating the use of and exposure to tobacco problems should be emphasized (USDHHS, 2014).

RENAL AND GENITOURINARY SYSTEMS

In normal aging, the mass of the kidney declines with a loss of functional glomeruli and tubules in addition to a reduction in blood flow. Concomitantly, changes occur in the activity of the regulatory hormones, vasopressin (antidiuretic hormone), atrial natriuretic hormone, and the renin–angiotensin–aldosterone system (Miller, 2009). These alterations combine to result in diminished glomerular filtration rate (GFR), with a 10% decrement per decade starting at age 30 years, as well as impaired electrolyte and water management (Beck, 1998).

Despite these changes, the older adult maintains the ability to regulate fluid balance under baseline conditions; however, with age, the renal system is more limited in its capacity to respond to externally imposed stresses. This reduced functional reserve increases vulnerability to disturbances in fluid homeostasis as well as to renal complications and failure (Lerma, 2009), particularly from fluid/electrolyte overload and deficit, medications, or illness (Miller, 2009).

The decline in functional nephrons emphasizes the risk from nephrotoxic agents including nonsteroidal anti-inflammatory drugs (NSAIDs), beta-lactam antibiotics, and radiocontrast dyes. Reduced GFR impairs the older adult’s ability to excrete renally cleared medications, such as aminoglycoside antibiotics (e.g., gentamicin) and digoxin, increasing the risk of adverse drug reactions (Beyth & Shorr, 2002). Dosages should be based on GFR estimated by the Cockcroft–Gault equation for creatinine clearance (Péquignot et al., 2009) or the modification of diet in renal disease (MDRD), rather than by serum creatinine concentration (Miller, 2009; National Kidney Disease Education Program, 2012). Values of serum creatinine remain unchanged despite an age-associated decline in GFR because of the parallel decrease in both older adults’ skeletal muscle mass, which produces creatinine, and GFR for creatinine elimination. Thus, serum creatinine levels overestimate GFR to result in potential drug overdose (Beck, 1998).

Increased risk of electrolyte imbalances can result from an age-dependent impairment in the excretion of excessive sodium loads, particularly in heart failure and with NSAID use, leading to intravascular volume overload. Clinical indicators include weight gain (greater than 2%); intake greater than output; edema; change in mental status; tachycardia; bounding pulse; pulmonary congestion with dyspnea, rales; increased BP and central venous pressure (CVP); as well as distended neck/peripheral veins (Beck, 1998).

Conversely, sodium wasting or excess sodium excretion when maximal sodium conservation is needed can occur with diarrhea. Hypovolemia and dehydration may ensue (Stern, 2006), manifesting as acute change in mental status (may be the initial symptom), weight loss (greater than 2%), decreased tissue turgor, dry oral mucosa, tachycardia, decreased BP, postural hypotension, flat neck veins, poor capillary refill, oliguria (less than 30 mL/hr), increased hematocrit and specific gravity of urine, and blood urea nitrogen (BUN): plasma creatinine ratio greater than 20:1, and serum osmolality greater than 300 mOsm/kg (Mentes, 2006).

Impaired potassium excretion puts the older adult at risk for hyperkalemia, particularly in heart failure and with use of potassium supplements, potassium-sparing diuretics, NSAIDs, and angiotensin-converting enzyme (ACE) inhibitors (Mick & Ackerman, 2004). Clinical indicators include diarrhea, change in mental status, cardiac dysrhythmias or arrest, muscle weakness and areflexia, paresthesias and numbness in extremities, EKG abnormalities, and serum potassium greater than 5.0 mEq/L (Beck, 1998).

Limited acid excretion capability can cause metabolic acidosis during acute illness in the older adult. This condition presents as Kussmaul’s respirations, change in mental status, nausea, vomiting, arterial blood pH less than 7.35, serum bicarbonate less than 22 mEq/L, and PaCO₂ less than 38 mmHg with respiratory compensation (Beck, 1998).

Causes of abnormal water metabolism with age include diminution in maximal urine concentrating ability (Sands, 2012), which, in concert with blunted thirst sensation and total body water, can result in hypertonic dehydration and hypernatremia (Mentes, 2006). Often associated with insensible fluid loss from fever (Miller, 2009), hypernatremia presents with thirst; dry oral mucosa; dry, furrowed tongue; postural hypotension; weakness; lethargy; serum sodium less than 150 mEq/L; and serum osmolality less than 290 mOsm/kg. Disorientation, seizures, and coma occur in severe hypernatremia (Suhayda & Walton, 2002).

Impaired excretion of a water load, exacerbated by ACE inhibitors, thiazide diuretics (Miller, 2009), and selective serotonin reuptake inhibitors (SSRIs; Mentes, 2006), predisposes the older adult to water intoxication and hyponatremia (Beck, 1998). Clinical indicators involve lethargy, nausea, muscle weakness and cramps, serum sodium less than 135 mEq/L, and serum osmolality less than 290 mOsm/kg. Confusion, coma, and seizures are seen in severe hyponatremia (Suhayda & Walton, 2002).

Changes in the lower urinary tract with age include reduced bladder elasticity and innervation, which contribute to decreases in urine flow rate, voided volume, and bladder capacity, as well as increases in postvoid residual and involuntary bladder contractions. A delayed or decreased perception of the signal from the bladder to void and decline in pelvic floor functioning (Ellsworth, Marschall-Kehrel, King, & Lukacz, 2013) translate into urinary urgency (Kevorkian, 2004). Increased nocturnal urine flow, which results from altered regulatory hormone production, impaired ability to concentrate urine (Sands, 2012), and bladder-muscle instability, can lead to nocturnal polyuria (Miller, 2009). In older men, benign prostatic hyperplasia (BPH) can result in urinary urgency, hesitancy, and frequency. All these changes combine to increase the risk of urinary incontinence in the older adult. Furthermore, urgency and nocturia increase the risk of falls. Changes with age in the physiology of the urinary tract, such as increased vaginal pH and decreased antibacterial activity of urine, in addition to the functional changes of the bladder, contribute to the development of bacteriuria, with potential for urinary tract infection (UTI; Htwe et al., 2007; Stern, 2006).

Renal assessment includes monitoring for renal function (GFR) based on creatinine clearance, particularly in acute and chronic illnesses (Lerma, 2009; Miller, 2009; Péquignot et al., 2009). The choice, dose, need, and alternatives for nephrotoxic and renally excreted agents should be considered (Beyth & Shorr, 2002).

Dehydration, volume overload, and electrolyte status are assessed first by screening for risk of fluid and electrolyte imbalances based on the older adult’s age, medical and nutritional history, medications, cognitive and functional abilities, psychosocial status, and bowel and bladder patterns. Data on fluid intake and output; daily weights; and vital signs, including orthostatic BP measurements, are needed. Heart rate is a less reliable indicator for dehydration in older adults because of the effects of medications and heart disease (Suhayda & Walton, 2002).

Physical assessment for fluid/electrolyte status focuses on skin for edema and turgor. Note that turgor in older adults is a less reliable indicator for dehydration because of poor skin elasticity, and assessment over the sternum or inner thigh is recommended. Additional assessment involves the oral mucosa for dryness as well as cardiovascular, respiratory, and neurologic systems. Acute changes in mental status, reasoning, memory, or attention may be initial symptoms of dehydration (Suhayda & Walton, 2002). Pertinent laboratory tests include serum electrolytes, serum osmolality, complete blood count (CBC), urine pH and specific gravity, BUN, hematocrit (Mentes, 2006), and arterial blood gases (Beck, 1998).

Evaluations of urinary incontinence, UTI, and nocturnal polyuria using a 72-hour voiding diary are recommended. See Atypical Presentation of Disease section that follows UTI discussion. Voiding history and rectal examination are required to diagnose BPH (see Chapter 21, “Urinary Incontinence”). Fall risk should be addressed when nocturnal or urgent voiding is present (see Chapter 19, “Preventing Falls in Acute Care”).

Ongoing care involves monitoring for renal function (Lerma, 2009; Miller, 2009; Péquignot et al., 2009) and for levels of nephrotoxic and renally cleared drugs (Beyth & Shorr, 2002). Maintenance of fluid/electrolyte balance is paramount (Beck, 1998), especially if fluids are given intravenously (Doerflinger, 2009). To prevent dehydration, older adults weighing between 50 and 80 kg (110 and 176 lb) are advised to have a minimum fluid intake of 1,500 to 2,500 mL/d (unless contraindicated by the medical condition; Suhayda & Walton, 2002) from both fluids and food sources, including fruits, vegetables, soups, and gelatin, with avoidance of high salt and caffeine content (Mentes, 2006; Ney, Weiss, Kind, & Robbins, 2009).

Incontinence care and exercise can contribute to management of voiding problems, including reduced incontinence, of older adults (Kim, Suzuki, Yoshida, & Yoshida, 2007; Schnelle et al., 2002). Behavioral interventions recommended for nocturnal polyuria include limited fluid intake in the evening, avoidance of caffeine and alcohol, and a prompted-voiding schedule (Miller, 2009). Institution of safety precautions and fall-prevention strategies are needed in nocturnal or urgent voiding (see Chapter 19).

OROPHARYNGEAL AND GASTROINTESTINAL SYSTEMS

Age-specific alterations in the oral cavity can adversely affect the older adult’s nutritional status. Deterioration in the strength of muscles of mastication as well as potential for tooth loss and xerostomia because of dehydration or medications may reduce food intake (Hall, 2009). Contributing to poor appetite are an altered taste perception and a diminished sense of smell (see Chapter 8, “Oral Health Care”; Ney et al., 2009; Visvanathan & Chapman, 2009).

Changes in the esophagus with age include delayed emptying in addition to decreases in upper and lower esophageal sphincter pressures, sphincter relaxation, and peristaltic contractions. Swallowing becomes slower and less efficient (Logemann, Curro, Pauloski, & Gensler, 2013). Although these alterations rarely impair esophageal function and swallowing sufficiently to cause dysphagia or aspiration in normal aging, such conditions can develop in conjunction with disease or medication side effects in older adults (Gregersen, Pedersen, & Drewes, 2008; Ney et al., 2009). Diminished gastric motility with delayed emptying contributes to altered oral-drug passage time and absorption in the stomach; elevated risk of gastroesophageal reflux disease (GERD; Hall, 2009); and decreased postprandial hunger, leading to diminished food intake and possible malnutrition (Visvanathan & Chapman, 2009). Reduced mucin secretion impairs the protective function of the gastric mucosal barrier and increases the incidence of NSAID-induced gastric ulcerations (Newton, 2005). Although the motility and most absorptive functions of the small intestine are preserved with age, absorption of vitamin B₁₂, folic acid, and carbohydrates declines (Hall, 2009). In addition, malabsorption of calcium and vitamin D contributes to the risk of osteoporosis. Supplementation with calcium and vitamins D and B₁₂ is now recommended for older adults (U.S. Department of Agriculture [USDA] & USDHHS, 2010; Visvanathan & Chapman, 2009).

Age-dependent weakening of the large-intestine wall predisposes older adults to diverticulosis and may lead to diverticulitis (Hall, 2009). Because motility of the colon appears to be preserved with age, increased self-reports of constipation in older adults may be attributed instead to altered dietary intake, medications, inactivity, or illness. Diminished rectal elasticity, internal anal sphincter thickening, and impaired sensation to defecate contribute to the risk of fecal incontinence in older adults (Gallagher et al., 2008), although this condition is primarily found in combination with previous bowel surgery or disease and not in normal aging (Hall, 2009).

Pancreatic exocrine output of digestive enzymes is preserved to allow normal digestive capacity with aging (Hall, 2009). Regarding endocrine function, aging changes in carbohydrate metabolism allow a genetic predisposition for diabetes to become manifest (Meneilly, 2010). An age-related decrease in gallbladder function increases the risk of gallstone formation. Although liver size and blood flow decline with age, reserve capacity maintains adequate hepatic function, and values of liver function tests remain stable; however, the liver is more susceptible to damage by stressors, including alcohol and tobacco. Associated with changes in the hepatic and intestinal cytochrome P450 system (Hall, 2009), clearance of a range of medications, including many benzodiazepines, declines to result in increased potential for dose-dependent adverse reactions to these drugs (Beyth & Shorr, 2002).

Reductions in antimicrobial activity of saliva and immune response of the gastrointestinal tract with age contribute to a high risk for infectious and inflammatory diseases of this system (Htwe et al., 2007). Furthermore, impaired enteric neuronal function may blunt the older adult’s reaction to infection and inflammation and result in atypical presentation of disease (see Atypical Presentation of Disease section; Hall, 2002).

In the gastrointestinal evaluation, the abdomen and bowel sounds are assessed. Liver size, as well as reports of pain, anorexia, nausea, vomiting, and altered bowel habits should be noted (Visvanathan & Chapman, 2009). Assessment of the oral cavity includes dentition and chewing capacity (Chapman, 2007; see Chapter 8).

Weight is monitored with calculation of BMI and compared to recommended values (American Heart Association Nutrition Committee; Lichtenstein et al., 2006; Visvanathan & Chapman, 2009). Deficiencies in diet can be identified through comparisons of dietary intake, using a 24- to 72-hour food intake record, with nutritional guidelines (Chapman, 2007; Roberts & Dallal, 2005; USDA & USDHHS, 2010). In addition, laboratory values of serum albumin, prealbumin, and transferrin are useful nutritional indicators. Low albumin concentration can also affect efficacy and potential for toxicity of selected drugs, including digoxin and warfarin (Beyth & Shorr, 2002). Several instruments for screening the nutritional status, eating habits, and appetite of older adults are available (see Resources section and Chapter 10, “Nutrition”; Ney et al., 2009).

Signs of dysphagia, such as coughing or choking with solid or liquid food intake, should be reported for further evaluation. If aspiration from dysphagia is suspected, the lungs must be assessed for the presence of infection, typically indicated by unilateral or bilateral basilar crackles in the lungs, dyspnea, tachypnea, and cough (Imperato & Sanchez, 2006). A decline in function or change in mental status may signal atypical presentation of respiratory infection from aspiration (Ney et al., 2009). Evaluation of GERD is based on typical and atypical symptoms (see Atypical Presentation of Disease section; Hall, 2009).

To assess constipation or fecal incontinence, a careful history with a 2-week bowel log noting laxative use is needed. Fecal impaction is assessed by digital examination of the rectum as a hardened mass of feces, which can be palpated. The impaction may also be palpated through the abdomen (Gallagher et al., 2008).

For continuing care, referrals should be provided to a registered dietitian for poor food intake, unhealthy BMI (healthy BMI: 18.5–24.9 kg/m²; overweight: 25–29.9 kg/m²; obesity: 30 kg/m² or greater; American Heart Association Nutrition Committee; Lichtenstein et al., 2006), and unintentional weight loss of 10% or greater in 6 months (Chapman, 2007; Ney et al., 2009). Drug levels and liver function tests are monitored if drugs are metabolized hepatically (Beyth & Shorr, 2002). Explanation of normal bowel frequency, the importance of diet and exercise, and recommended types of laxatives addresses constipation problems (Gallagher et al., 2008). Mobility should be encouraged to prevent constipation, and prophylactic laxatives should be provided if constipating medications, such as opiates, are prescribed (Stern, 2006). Community-based food and nutrition programs (Visvanathan & Chapman, 2009) and education on healthful diets using the food pyramid for older adults may be useful in improving dietary intake (see Chapter 10; USDA & USDHHS, 2010).

MUSCULOSKELETAL SYSTEM

Musculoskeletal tissues undergo age-associated changes that can negatively impact function in the older adult. Sarcopenia is defined as reduced muscle mass, physical performance, and grip strength (Cederholm & Morley, 2015). A decline in the size, number, and quality of skeletal muscle fibers occurs with aging and lean body mass is replaced by fat and fibrous tissue (Loeser & Delbono, 2009) so that by age 75 years, only 15% of the total body mass is muscle compared to 30% in a young, healthy adult (Matsumura & Ambrose, 2006). These alterations result in diminished contractile muscle force with increased weakness and fatigue plus poor exercise tolerance. Age-specific physiological alterations contributing to sarcopenia include reductions in muscle innervation, insulin activity, and sex steroid (estrogen and testosterone) and growth hormone levels. Additionally, individual factors, such as weight loss, protein deficiency, and physical inactivity, can accelerate development of this condition so it progresses to a clinically significant problem (Jones et al., 2009). Sarcopenia has been documented to affect function adversely in older adults by increasing the risk of disability, falls, unstable gait, and need for assistive devices. Physical activity, particularly strength training, and adequate intake of energy and protein can prevent or reverse sarcopenia (Narici, Maffulli, & Maganaris, 2008).

Age-dependent bone loss occurs in both sexes and at all sites in the skeleton. Whereas bone mass peaks between ages 30 and 35 years, density decreases thereafter at a rate of 0.5% per year. This decrement, caused by reduced osteoblast activity in the deposition of new bone, is accompanied by deterioration in bone architecture and strength. Furthermore, from 5 to 7 years following menopause during estrogen decline, bone loss in women accelerates to a 3% to 5% annual rate (USDHHS, 2004). This loss, resulting from osteoclast activation with elevated bone breakdown or resorption, occurs mainly in cancellous or trabecular bone, such as the vertebral body, and may develop into type I osteoporosis in women aged 51 to 75 years, who risk vertebral fractures. Following this postmenopausal period, bone loss slows again in women and involves cortical bone in the long bones of the extremities. With aging, both women and men may develop type II osteoporosis and are susceptible to hip fractures and kyphosis from vertebral compression fractures in later life (Simon, 2005).

An age-associated decline in the strength of ligaments and tendons, which are integral to normal joint function, predisposes to increased ligament and tendon injury, more limited joint range of motion (ROM), and reduced joint stability, leading to osteoarthritis (Narici et al., 2008). Degeneration of intervertebral disks caused by dehydration and poor nutrient influx elevates the risk of spinal osteoarthritis, spondylosis, and stenosis with aging (Loeser & Delbono, 2009).

Age-related changes in articular cartilage, which covers the bone endings in joints to allow smooth movement, involve increased dehydration, stiffening, crystal formation, calcification, and roughening of the cartilage surface. Although these alterations have a minor effect on joint function under baseline conditions, the aging joint is less capable of withstanding mechanical stress, such as the stress caused by obesity or excess physical activity, and is also more susceptible to diseases, including osteoarthritis (Loeser, 2010).

Age-dependent changes in stature include dorsal kyphosis, reduction in height, flexion of the hips and knees, and a backward tilt of the head to compensate for the thoracic curvature. A shorter stride, reduced velocity, and broader base of support with feet more widely spaced characterize modifications in gait with age (Harris et al., 2008).

The musculoskeletal assessment includes inspection of posture, gait, balance, symmetry of body parts, and alignment of extremities. Kyphosis, bony enlargements, or other abnormalities should be noted. The clinician should palpate bones, joints, and surrounding muscles, evaluating muscle strength on a scale of 0/5, and noting symmetry and signs of atrophy of major upper and lower extremity muscle groups. Active and passive ROM for major joints are evaluated, noting pain, limitation of ROM, and joint laxity. Joint stabilization and slow movements in ROM examinations are advised to prevent injury. Functionality, mobility, fine and gross motor skills, balance, and fall risk should be assessed (see Chapter 7, “Assessment of Physical Function,” and Chapter 19; Harris et al., 2008).

For continuing care, referrals to physical or occupational therapy may be appropriate. Increased physical activity, including aerobic (American College of Sports Medicine; Chodzko-Zajko et al., 2009) and ROM (Netz et al., 2005) exercise plus training programs to increase muscle strength and power (i.e., ability to produce force) (Narici et al., 2008), is recommended to maintain maximal function. Interventions to promote such behavior in older adults involve health education, goal setting, and self-monitoring (Conn, Minor, Burks, Rantz, & Pomeroy, 2003). Pain medication may be needed to enhance functionality (see Chapter 18, “Pain Management”; McCleane, 2008). Strategies to prevent falls (see Chapter 19) and avoid physical restraints (see Chapter 23, “Physical Restraints and Side Rails in Acute and Critical Care Settings”) are appropriate.

To prevent and treat osteoporosis, adequate daily intake of calcium (1,200 mg for women aged 50 years and older) and vitamin D (400 IU for women aged 50 to 70 years and 600 IU for women aged 71 years and older), physical exercise, and smoking cessation are recommended (USDHHS, 2004). In addition, routine bone mineral density screening for osteoporosis is advised for women aged 65 years and older, as well as for women aged 60 to 64 years at increased risk for osteoporotic fractures (Agency for Healthcare Research and Quality [AHRQ], 2014).

NERVOUS SYSTEM AND COGNITION

Age-related alterations in the nervous system can affect function and cognition in older adults. Changes include a reduced number of cerebral and peripheral neurons (Hall, 2002), modifications in dendrites and glial support cells in the brain, and loss and remodeling of synapses. Decreased levels of neurotransmitters, particularly dopamine, as well as deficits in systems that relay signals between neurons and regulate neuronal plasticity also occur with aging (Mattson, 2009).

Combined, these neurological changes contribute to decrements in general muscle strength; deep tendon reflexes; sensation of touch, pain, and vibration; and nerve conduction velocity (Hall, 2002), which result in slowed coordinated movements and increased response time to stimuli (Matsumura & Ambrose, 2006). These clinical consequences, although relatively mild in normal aging, cause an overall slowing of motor skills with potential deficits in balance, gait, coordination, reaction time, and agility (Harris et al., 2008; Narici et al., 2008). Such decline in function can adversely affect an older adult’s daily activities, notably ambulation and driving, and predispose to falls and injury (American College of Sports Medicine; Chodzko-Zajko et al., 2009; Craft, Cholerton, & Reger, 2009).

Neurological changes, along with thinning of the skin, compromise thermoregulation in the older adult. These result in decreased sensitivity to ambient temperature as well as impaired heat conservation, production, and dissipation with predisposition to hypothermia and hyperthermia (Kuchel, 2009). Febrile responses to infection may be blunted or absent (see Atypical Presentation of Disease section; High, 2009; Htwe et al., 2007; Watters, 2002).

With age, the speed of cognitive processing slows (Harada et al., 2013) and some degree of cognitive decline is common (Park, O’Connell, & Thomson, 2003) but not universal in the older adult population (Stewart, 2004). Older adults demonstrate significant heterogeneity in cognitive performance, which may be positively impacted by education, good health, and physical activity (Colcombe & Kramer, 2003).

Specific cognitive abilities exhibit differing levels of stability or decline with age. For example, crystallized intelligence, or the information and skills acquired from experience, remains largely intact, whereas fluid intelligence, or creative reasoning and problem solving, declines (Harada et al., 2013). Sustained attention is unaffected by aging, although divided attention, or the ability to concentrate on multiple tasks concurrently, deteriorates. The mild decline in executive function, which includes the capability of directing behavior and completing multistep tasks, usually has minimal impact on an older adult’s ability to manage daily activities. Although language abilities and comprehension appear stable, spontaneous word finding may deteriorate and is often a complaint of older adults. Remote memory, or recalling events in the distant past, and procedural memory, or remembering ways to perform tasks, remain intact but declarative memory, or learning new information, is slowed (Craft et al., 2009). However, despite some deficits, memory functions are adequate for normal life in successful aging (Henry, MacLeod, Phillips, & Crawford, 2004).

Changes in the nervous system increase the risk of sleep disorders (Espiritu, 2008) and delirium in the older adult, especially in acute care (see Chapter 17, “Delirium: Prevention, Early Recognition, and Treatment”). Neural changes affect the perception, tolerance, and response to treatment of pain (McCleane, 2008). In addition, age-specific alterations predispose neurons to degeneration, contributing to Alzheimer’s disease (Charter & Alekoumbides, 2004), Parkinson’s disease, and Huntington’s disease (Mattson, 2009).

Assessment, with periodic reassessment, of baseline functional status (see Chapter 7) should include evaluation of fall risk, gait, and balance (see Chapter 19) as well as basic, instrumental, and advanced activities of daily living (ADL). During acute illness, functional status, pain (see Chapter 18), and symptoms of delirium (see Chapter 17) should be monitored. Evaluation of baseline cognition with periodic reassessment (see Chapter 6, “Assessing Cognitive Function”) and sleep disorders (Espiritu, 2008) is warranted. The impact of physical and cognitive changes of aging on an older adult’s level of safety and attentiveness in daily tasks should be determined (Craft et al., 2009; Harada et al., 2013; Henry et al., 2004; Park et al., 2003). Temperature indicating hypothermia (less than 95°F or less than 35°C) or hyperthermia (greater than 105°F or greater than 40.6°C) must be closely watched (Kuchel, 2009; Lu, Leasure, & Dai, 2010).

For care of the older adult, fall-prevention strategies should be implemented (see Chapter 19). If delirium is identified, nursing interventions for its treatment are needed (see Chapter 17). Particularly during surgery, procedures, such as the use of warmed intravenous fluids, humidified gases, and temperature-regulating blankets (Doerflinger, 2009), should be instituted to maintain normal temperatures and prevent hypothermia in the older patient (Watters, 2002). Lifestyle modifications recommended to improve cognitive function include regular physical exercise (Colcombe & Kramer, 2003), intellectual stimulation (Harada et al., 2013), and a healthful diet (JNC, 2004; USDA & USDHHD, 2010). Behavioral interventions for sleep disorders may be warranted (Irwin, Cole, & Nicassio, 2006).

IMMUNE SYSTEM AND VACCINATION

Immunosenescence, or the age-related dysfunction in immune response, is characterized by reduced cell-mediated immune function and humoral immune responses (Weiskopf, Weinberger, & Grubeck-Loebenstein, 2009), as well as increased inflammatory response (High, 2009; Hunt, Walsh, Voegeli, & Roberts, 2010). In older adults, immunosenescence is responsible, in part, for the increased susceptibility to and severity of infectious diseases (Htwe et al., 2007), the lower efficacy of vaccination (Weiskopf et al., 2009), and the chronic inflammatory state, which may contribute to chronic disease with age (Hunt et al., 2010).

Infectious diseases are a critical threat to older adults, especially because vaccination efficacy declines with age. Mortality rates for infectious diseases are highest for adults older than 85 years (Htwe et al., 2007), whereas reactivation of viruses, particularly varicella zoster leading to herpes zoster, occurs significantly more frequently in older adults (High, 2009). Immunosenescence, by dampening the induction of adaptive immune responses, results in reduced response rates to vaccination. For example, influenza vaccination has a protection rate of only 56% in older persons. Furthermore, antibody titers following booster vaccinations, such as against tetanus, are lower and decline faster with diminished antibody function in older adults compared to younger individuals (Weiskopf et al., 2009).

Current immunization recommendations for older adults are available from the Centers for Disease Control and Prevention (CDC, 2015). Vaccination with pneumococcal polysaccharide for pneumococcal infections is recommended for individuals 65 years of age and older, with one-time revaccination indicated if the patient was vaccinated 5 or more years previously and was aged younger than 65 years at the time of primary vaccination. For seasonal influenza, all individuals 50 years of age and older should be vaccinated with the inactivated vaccine just prior to influenza season each year. A single dose of zoster vaccine is recommended for all adults 60 years of age and older regardless of prior zoster history. A complete tetanus vaccine series is indicated for individuals having an uncertain history of tetanus immunization or having received fewer than three doses. Boosters should be given at 10-year intervals or more frequently with high-risk injuries. Hepatitis vaccines should also be considered for older adults depending on circumstances such as potential exposure and travel (CDC, 2015; High, 2009).

ATYPICAL PRESENTATION OF DISEASE

Diseases, particularly infections, often manifest with atypical features in older adults. Signs and symptoms are frequently subtle in the very old. These may initially involve nonspecific declines in functional or mental status, anorexia with reduced oral intake, incontinence, falls (Htwe et al., 2007), fatigue (Hall, 2002), or exacerbation of chronic illness such as heart failure or diabetes (High, 2009).

As a presenting sign of infection, fever is often blunted or absent, particularly in very old (High, 2009), frail, or malnourished (Watters, 2002) adults. Compared to young adults with a normal mean baseline body temperature of 98.6°F (37°C), frail older adults have a lower mean oral baseline temperature of 97.4°F (36.3°C; Lu et al., 2010). A blunted response to inflammatory stimuli in combination with lower basal temperature can result in a lack of measurable febrile response. Increasing age is a predisposing factor for the absence of fever (Htwe et al., 2007).

Assessment of the older patient should note any changes from baseline (including those that are subtle and nonspecific) in functioning, mental status and behavior (e.g., increased/new onset confusion), appetite, or exacerbation of chronic illness (High, 2009; Watters, 2002). This is especially important in individuals with cognitive impairment who are unable to describe symptoms.

To detect fever, normal temperature should be established for the older adult and monitored for changes of 2°F to 2.4°F (1.1–1.3°C) above baseline (Htwe et al., 2007). Oral temperatures of 99°F (37.2°C) or greater on repeated measurements also can be used to signify fever. The difficulty of diagnosing infection based on signs and symptoms may result in greater reliance on laboratory and radiologic evaluations (High, 2009).

In the assessment of disease, both typical and atypical symptoms must be considered. Evaluation for pneumococcal pneumonia includes monitoring for typical symptoms, such as productive cough, fever, chills, and dyspnea, as well as insidious, atypical symptoms, including tachypnea, lethargy (Bartlett et al., 2000), weakness, falls, decline in functional status, delirium, or increased/new-onset confusion with absent high fever. Decreased appetite and dehydration may be the only initial symptoms in the older adult (Imperato & Sanchez, 2006). Although chest radiograph is basic to diagnosis, the older adult who is dehydrated may not show infiltrate or consolidation, and these findings may appear only after hydration (Htwe et al., 2007).

Clinical features of tuberculosis in the older person are often atypical and nonspecific. Presenting symptoms may include dizziness, nonspecific pain, or impaired cognition rather than the typical manifestations of fever, night sweats, cough, or hemoptysis (High, 2009). Typical influenza symptoms of cough, fever, and chills may be combined with altered mental status in older adults (Htwe et al., 2007).

In an acute myocardial infarction, the classic presentation of severe chest pain and diaphoresis may be replaced by dyspnea, confusion, and anxiety (Gray-Vickrey, 2010).

UTI in older adults may present with classical symptoms of dysuria, flank or suprapubic discomfort, hematuria, and urinary frequency and urgency, or atypical symptoms of new-onset/worsening incontinence, anorexia, confusion, nocturia, or enuresis (Htwe et al., 2007).

For peritonitis, atypical symptoms, such as confusion and fatigue, may be manifest rather than the typical symptoms of rigidity (Hall, 2002). Evaluation of GERD is based on typical presenting symptoms of heartburn (pyrosis) and acid regurgitation, as well as atypical symptoms in the older adult of dysphagia, chest pain, hoarseness, vomiting, chronic cough, or recurrent aspiration pneumonia (Hall, 2009).

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