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Body and Metabolic Changes in the Older Adult

Skin and Hair

With aging, the skin atrophies; the epidermis and dermis thin and there is less subdermal fat and less collagen (less elasticity). Skin is fragile and slower to heal. Oil production is lower and skin drier (xerosis) due to decreased sebaceous and sweat gland activity. There is a decrease in the skin’s sensory ability and reduction in vitamin D synthesis. Fewer melanocytes lead to graying of hair.

Seborrheic Keratoses

Soft wart-like skin lesions that appear “pasted on.” Mostly seen on the back and trunk. Benign.

Senile Purpura

Bright purple-colored patches with well-demarcated edges. Located on the dorsum of the forearms and hands. Lesions eventually resolve over several weeks. Benign.

Lentigines

Also known as “liver spots.” Tan- to brown-colored macules on the dorsum of the hands and forearms caused by sun damage. More common in light-skinned individuals. Benign.

Stasis Dermatitis

Statis dermatitis affects primarily the lower legs and ankles secondary to chronic edema (from peripheral vascular disease [PVD])

Senile Actinic Keratosis (Solar Keratosis)

Condition is secondary to sun exposure and has the potential for malignancy. It has the potential to be a precancerous lesion of squamous cell carcinoma.

Nails

Growth slows and nails become brittle, yellow, and thicker. Longitudinal ridges develop.

Eyes

Presbyopia is caused by loss of elasticity of the lenses, which makes it difficult to focus on close objects. Close vision is markedly affected. Onset is during early to mid-40s. Can be remedied with “reading glasses” or bifocal lenses. Cornea is less sensitive to touch. Arcus senilis, cataracts, and glaucoma are more common.

438Arcus Senilis (Corneal Arcus)

Opaque grayish-to-white ring at the periphery of the cornea. Develops gradually and is not associated with visual changes. Caused by deposition of cholesterol and fat. In patients younger than 40 years, can be a sign of elevated cholesterol. Check fasting lipid profile.

Cataracts

Cloudiness and opacity of the lens of the eye(s) or its envelope (posterior capsular cataract). There are three types (nuclear, cortical, and posterior capsular). Color of the lens is white to gray. Cataracts cause gradual onset of decreased night vision, sensitivity to glare of car lights (driving at night), and hazy vision. The red reflex disappears.

Test: Red reflex (reflection is opaque gray versus orange-red glow)

Macular Degeneration

Loss of central visual fields results in loss of visual acuity and contrast sensitivity. May find drusen bodies. Use Amsler grid to evaluate central-vision changes.

Ears

Presbycusis (Sensorineural Hearing Loss)

High-frequency hearing is lost first (e.g., a speaking voice is an example of high-frequency). Presbycusis starts at about age 50 years. There are degenerative changes of the ossicles, fewer auditory neurons, and atrophy of the hair cells resulting in sensorineural hearing loss.

Heart

Elongation and tortuosity (twisting) of the arteries occurs. Thickened intimal layer of arteries and arteriosclerosis result in increased systolic BP due to increased vascular resistance (isolated systolic hypertension). The mitral and aortic valves and may contain calcium deposits.

Baroreceptors are less sensitive to changes in position. There is decreased sensitivity of the autonomic nervous system. BP response is blunted. Maximum heart rate decreases. There is higher risk of orthostatic hypotension. S4 heart sound is a normal finding in the elderly if not associated with heart disease. The left ventricle hypertrophies with aging (up to 10% increase in thickness).

Lungs

Total lung capacity remains relatively the same as we age. Forced vital capacity (FVC) decreases with age. Forced expiratory volume in 1 second (FEV1) decreases with age. Residual volume (air left in the lungs at the end of expiration) increases with age due to decrease in lung and chest wall compliance. The chest wall becomes stiffer and the diaphragm is flatter and less efficient.

Mucociliary clearance (fewer cilia) and coughing are less efficient. The airways collapse sooner during expiration. Responses to hypoxia and hypercapnia decreases. Decreased breath sounds and crackles are commonly found in the lung bases of elderly patients without presence of disease. Instruct the patient to “cough” several times to inflate the lung bases (the benign crackles will disappear). There is increased anterior–posterior (AP) diameter related to normal body changes.

Liver

Liver size and mass decreases due to atrophy (20%–40%). Liver blood flow and perfusion decrease (up to 50% in some elders). Fat (lipofuscin) deposition in the liver is more common. 439The liver function test result (ALT, AST, alkaline phosphatase) is not significantly changed. Metabolic clearance of drugs is slowed by 20% to 40% because the cytochrome P450 (CYP450) enzyme system is less efficient. The LDL and cholesterol levels increase with aging.

Renal System

Renal size and mass decrease by 25% to 30%. The steepest decline in renal mass occurs after the age of 50. Starting at the age of 40 years, the glomerular filtration rate (GFR) starts to decrease. By age 70, up to 30% of renal function is lost. Renal clearance of drugs is less efficient. The serum creatinine is a less reliable indicator of renal function in the elderly due to the decrease in muscle mass, creatine production, and creatinine clearance. Serum creatinine can be in the normal range, even if renal function is markedly reduced. The risk of kidney damage from nonsteroidal anti-inflammatory drugs (NSAIDs) is much higher. The renin–angiotensin levels are lower in the elderly.

Genitourinary System

The amount of urine that remains in the bladder after urination is completed (residual urine) increases with age. Normally, the bladder holds approximately 300 to 400 mL. In postmenopausal women, the urethra becomes thinner and shortens and the ability of the urinary sphincter to close tightly decreases (due to declining estrogen). Urinary incontinence is two to three times more common in women. According to the Cleveland Clinic, erectile dysfunction affects 40% of men aged 40 years and 70% of men aged 70 years.

Musculoskeletal System

Older adults can lose a total of 1 to 3 inches (2.5–2.7 cm) in height; this loss becomes more rapid after age 70. Compression fractures of vertebrae are a sign of osteoporosis (kyphosis) and contribute to loss of height.

Deterioration of articular cartilage is common after age of 40. Stiffness in the morning that improves with activity is a common symptom of osteoarthritis (degenerative joint disease [DJD]). Fat mass increases but muscle mass and muscle strength markedly decrease, with more muscle loss in the legs compared with the arms. Bone resorption is more rapid than bone deposition in women compared with men (4:1). Fractures heal more slowly because of decrease in the number of osteoblasts.

Gastrointestinal System

Receding gums and dry mouth are common. Decreased sensitivity of the taste buds results in decrease in appetite. There is decreased efficiency in absorbing some vitamins (i.e., folic acid, vitamin B₁₂) and minerals (e.g., calcium) by the small intestines. Delayed gastric emptying occurs. Higher risk of gastritis and GI damage from decreased production of prostaglandins. Diverticuli are common. Large bowel (colon) transit time is slower. Constipation is more common. Increased risk of colon cancer (age >50 years is strongest risk factor). Fecal incontinence common due to drug side effects, underlying disease, neurogenic disorders, or a combination of these factors. Fecal impaction may lead to a small amount of runny soft stool. Laxative abuse is more common.

Endocrine System

Minor atrophy of the pancreas occurs. Increased levels of insulin are seen along with mild peripheral insulin resistance. Changes or disorders of the circadian rhythm hormonal secretion (growth hormone, melatonin, and other hormones) can cause changes in sleep patterns.

440Sex Hormones

Testes are active for the entire life cycle. Less dehydroepiandrosterone (DHEA) and testosterone are produced.

Estrogen and progesterone production decrease significantly in women due to ovarian failure (menopause).

Adipose tissue is able to synthesize very small amounts of estrogen. In the United States, up to 53% of those aged 65 to 74 years are sexually active (Stewart & Graham, 2013).

Immune System

Older adults are less likely to present with fever during infections. Typical body temperature is slightly lower. There is a decreased antibody response to vaccines. Immune system is less active and there is higher risk of infection.

Cellular immunity is affected more by aging than humoral immunity. Cellular or cell-mediated immunity involves the activity of T-lymphocytes, macrophages, and the cytokines. Humoral immunity is associated with B-lymphocytes and antibody (immunoglobulins or IgG) production.

Hematological System

There are no changes in the RBC life span, the blood volume, or the total number of circulating leukocytes. There is a higher risk of thrombi and emboli due to increased platelet responsiveness. Increased risk of iron and folate-deficiency anemia due to decreased efficiency of the GI tract to absorb vitamin B₁₂ and folate.

Neurological System

Cranial nerve testing may show differences in ability to differentiate color, papillary response, and decreased corneal reflex. Gag reflex decreases. Deep tendon reflexes may be brisk or absent. Neurological testing may be impaired by medications, causing slower reaction times. Benign essential tremor is more common.

Pharmacological Issues

Drug clearance is affected by renal impairment, less efficient liver CYP450 enzyme system, slow gastric emptying, increased gastric pH, decreased serum albumin, and relatively higher ratio of fat:muscle tissue (extends fat-soluble drugs). Older adults have an increased sensitivity to benzodiazepines and anticholinergic drugs such as hypnotics, tricyclic antidepressants (TCAs), antihistamines, and antipsychotics. The American Geriatrics Society has made a list of inappropriate medications for the elderly (Beers criteria; Agency for Healthcare Research and Quality, National Guideline Clearinghouse, & American Geriatrics Society, 2015).

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