Gerontology: Body and Metabolic Changes

Question 1

Physiologic Changes: Skin and Hair

Answer 1

• skin atrophies → epidermic and dermis thin, less subdermal fat and collagen (less elasticity)
• skin is fragile and lower to heal
• oil production is lower and skin drier (xerosis) d/t ↓ sebaceous and sweat gland activity
• ↓ in sensitivity to touch, vibration and temperature
• ↓ vit D synthesis
• fewer melanocytes → graying of hair

Question 2

Seborrheic Keratoses

Answer 2

• soft wartlike skin lesions
• appear “pasted on”
• mostly seen on back and trunk
• benign

Question 3

Senile Purpura

Answer 3

• bright purple-colored patches w/ well-demarcated edges
• located on extensors surfaces of forearms and hands after a minor trauma
• lesions eventually resolve over several weeks
• residuals are brown appearance when hemosiderin deposits in the tissue
• benign

Question 4

Lentingines

Answer 4

• aka “liver spots”
• tan- to brown-colored macules with a “moth-eaten” border on dorsum of hands and forearms caused by sun damage
• more common in light-skinned individuals
• benign

Question 5

Actinic Keratosis (Solar Keratosis)

Answer 5

• flat or thickened plaque w/ color varying from skin-colored to red, white or yellow
• may appear scaly or have a horny surface
• found on sun-damaged skin
• condition is secondary to sun exposure
• has the potential for malignancy
• precancerous form of squamous cell carcinoma

Question 6

Physiologic Changes: Nails

Answer 6

• growth slows
• nails become brittle, yellow, and thicker
• longitudinal ridges develop

Question 7

Physiologic Changes: Eyes

Answer 7

• presbyopia is caused by loss of elasticity of lenses, which makes it difficult to accommodate or focus on close objects
• close vision is markedly affected
• onset is during early to mid-40s
• can be remediated w/ “reading glasses” or bifocal lenses
• cornea is less sensitive to touch
• arcus senilis, cataracts, glaucoma, and macular degeneration are more common

Question 8

Arcus Senilis

Answer 8

Corneal Arcus
- opaque grayish-to-white ring w/ a sharp outer border
- indistinct central border at periphery of cornea
- typically bilateral; unilateral finding associated w/ contralateral carotid artery disease
- develops gradually, not associated w/ visual changes
- caused by deposition of lipids
- 60% of pts have evidence at age 60; nearly 100% at age 80
- in pts <40 years, can be a sign of elevated cholesterol
- chest fasting lipid profile

Question 9

Cataracts

Answer 9

• cloudiness and opacity of lens of the eye(s) or its envelope (posterior capsular cataract)

3 types:
- nuclear
- coprtical
- posterior capsular

• color of lens is white to gray
• cataracts cause gradual onset of ↓ night vision, sensitivity to glare of car lights (driving at night), halos around lights, blurry vision, and double vision
• red reflex disappears
• Mature cataracts appear white

Test: Red reflex (reflection os opaque gray vs. orange-red glow

• increase sensitivity to glare of car lights (driving at night)

Question 10

Glaucoma

Answer 10

• normally, anterior chamber of eye is modestly pressurized, helping to maintain eye’s shape → Aging is associated w/ loss of cells that help w/ efficient drainage of anterior chamber → loss causes ↑ anterior chamber pressure secondary to bottle neck at the drainage canal

Test: Visual fields and tonometer

Question 11

Macular Degeneration

Answer 11

• loss of central visual fields → loss of visual acuity and contrast sensitivity
• may fund drusen bodies

Test: Amsler grid to evaluate central-vision changes

** Most common cause of blindness in US is macular degeneration
- In developing countries, cataracts are the most common cause of blindness

Question 12

Physiologic Changes: Ears - Presbycusis

Answer 12

Presbycusis (Sensorineural Hearing Loss)
- high-frequency hearing is lost first (e.g., a speaking voice)
- Presbycusis starts at ~50 years
- degenerative changes of ossicles, fewer auditory neurons, and atrophy of hair cells resulting in sensorineural hearing loss

Question 13

Physiologic Changes: Heart

Answer 13

• Elongation and tortuosity (twisting) of the arteries occurs
• thickened intimal layer of arteries and arteriosclerosis → ↑ SBP d/t ↑ vascular resistance (isolated systolic HTN)
• MV and AV may contain calcium deposits
• baroreceptors are less sensitive ot change sin position
• ↓ sensitivity of autonomic nervous system
• BP response is blunted
• Maximum HR ↓
• higher risk of orthostatic hypotension
• S4 heart sound is a normal finding in elderly if not associated w/ heart disease
• LVH w/ aging (up to 10% increase in thickeness)

Question 14

Physiologic Changes: Lungs

Answer 14

• TLC remains relatively the same w/ aging
• FVC ↓ w/ aging
• FEV1 ↓ w/ aging
• Residual volume (air left in lungs at end of expiration) ↑ w/ age d/t ↓ in lung and chest wall compliance
• chest wall become stiffer
• diaphragm is flatter and less efficient
• Mucociliary clearance (fewer cilia) and coughing are less efficient
• smaller airways collapse sooner during expiration
• responses to hypoxia and hypercapnia ↓
• ↓ breath sounds and crackles are commonly found in lung bases o9f elderly pts w/out presence of disease

Instruct pts to “cough” several times to inflat ethe lung bases (the benign crackles will disappear)
- ↑ anterior-posterior (AP) diameter r/t normal body changes

Question 15

Physiologic Changes: Liver

Answer 15

• liver size and mass ↓ d/t atrophy (20-40%)
• liver blood flow and perfusion ↓ (up to 50% in some elders)
• fat (lipofuscin) deposition in liver is more common
• live function test result (ALT, AST, alkaline phosphatase) not significantly changed
• metabolic clearance of drugs is slowed by 20-40% d/t cytochrome P450 (CYP450) enzyme system is less efficient
• LDL and cholesterol levels ↑ w/ aging

Question 16

Physiologic Changes: Renal System

Answer 16

• renal size and mass ↓ by 25-30%
• steepest decline in renal mass occurs after age 50
• starting at age 40, GFR starts to ↓
• by age 70, up to 30% renal function is lost
• renal clearance of drugs, concentrating and diluting ability, and response to sodium is less effective
• serum creatinine is a less reliable indicator of renal function in elderly d/t ↓ muscle mass, creatine production, and creatinine clearance
• serum creatinine can be in the normal range, even if renal function is markedly reduced
• risk of kidney damage from NSAIDs is much higher
• renin and angiotensin II levels are lower in elderly

Question 17

Physiologic Changes: Genitourinary System

Answer 17

• capacity of the bladder ↓ w/a ge
• both compliance of bladder and rate of urine flow ↓
  → these factors contribute to ↑ amount of urine that remains in bladder after urination (residual urine)
• normally, bladder holds approx 300-400 mL
• prostatic hypertrophy occurs w/ age for men
• in postmenopausal women, the urethra becomes thinner and shortens; ability of urinary sphincter to close tightly ↓ (because of declining estrogen)
• urinary incontinence is 2-3x more common in women
• ED affects approx 40% of men aged 40 years and 70% of men aged 70

Question 18

Physiologic Changes: Musculoskeletal System

Answer 18

• muscle strength and power ↓ w/ age → can contribute to morbidity in elderly
• deterioration of articular cartilage is common after age 40
• stiffness in the morning that improves w/ activity is a common sx of osteoarthritis (degenerative joint disease [DJD])
• Bone resorption is more rapid than bone deposition in women compared w/ men (4:1)
• fractures heal more slowly d/t ↓ # of osteoblasts

Question 19

Physiologic Changes: Gastrointestinal System

Answer 19

• receding gums and dry mouth are common
• ↓ sensitivity of taste buds results in ↓ appetite
• ↓ efficiency in absorbing some vitamins (e.g., folic acid, vit B12), and minerals (e.g., calcium) by the small intestines
• delayed gastric emptying occurs
• higher risk of gastritis and GI damage from ↓ production of prostaglandins
• ↑ risk of colon cancer (age >50 years is strongest risk factor)
• Diverticuli are common
• Large bowel (colon) transit time is slower
• constipation is more common
• fecal impaction may lead to small amount of runny, soft stools
• laxative abuse is more common
• fecal incontinence may occur d/t loss of muscle mass and weakness of external anal sphincter, drug side effects, underly disease, neurogenic disorders, or a combination of these factors

Question 20

Physiologic Changes: Endocrine System

Answer 20

• minor atrophy of the pancreas occurs
• ↑ levels of insulin are seen along w/ mild peripheral insulin resistance
• changes or disorders of the circadian rhythm hormonal secretion (growth hormone, melatonin,a nd other hormones) can cause changes in sleep patterns

Question 21

Physiologic Changes: Sex Hormones

Answer 21

• Testes are active for the entire life cycle
• Dehydroepiandrosterone (DHEA) and testosterone production ↓ markedly w/ age
• estrogen and progesterone production ↓ significantly in women d/t ovarian failure (menopause)
• higher serum testosterone concentration in some postmenopausal women may cause frontal balding on the head and excess hair growth on mustache area and/or on chin
• adipose tissue is able to synthesize small amounts of estrogen and has been tied to gynecomastia in elderly men
• In US, up to 3% of those aged 65-74 are sexually active, and some studies have shown that older adults in their 80s can remain sexually active
• Some studies have shown that older adults in their 80s can remain sexually active
• by 70 years, ~70% of male shave ED
• Refer pt to urologist for treatment of ED that is not responding to usual doses of phosphodiesterase (PDE) inhibitors (sildenafil/Viagra, tadalafil/Cialis, vardenafil/Levitra, avanafil/Stendra) or have medical contraindications
• Advise pt to use condoms w/ new sexual partners to protect from STD and HIV infection

Question 22

Physiologic Changes: Immune System

Answer 22

• older adults are less likely to present w/ fever during infections
• typical body temp is slightly lower
• ↓ antibody response to vaccines
• immune system is less active; there is higher risk of infection
• cellular immunity is affected more by aging than humoral immunity
  -0 cellular or cell-mediated immunity involves activity of T-lymphocytes, macrophages, and cytokines
• Humoral immunity is associated w/ B-lymphocytes and antibody (immunoglobulins or IgG) production

Question 23

Physiologic Changes: Hematologic System

Answer 23

• no changes in RBC life span, the blood volume, or total number of circulation leukocytes
• higher risk of thrombi and emboli d/t ↑ platelet responsiveness
• ↑ risk of iron and folate-deficiency anemia d/t ↓ efficiency of GI tract to absorb vit B12 and folate

Question 24

Physiologic Changes: Neurologic System

Answer 24

• hallmark of aging is slowed reaction times, ↓ proprioception, and ↑ risk of falls
• cognitive function remains stable if no underlying dementia, but ability to solve problems is affected by reaction time
• cranial nerve testing may show differences in ability to differentiate color, pupillary response, and ↓ corneal reflex
• gag reflex ↓
• DTR may be brisk or absent
• neurologic testing may be impaired by medications, causing slower reaction times
• benign essential tremor is more common

Question 25

Physiologic Changes: Pharmocologic Issues

Answer 25

• drug clearance is affected by renal impairment, less efficient liver CYP450 enzyme system, slow gastric emptying, ↑ gastric pH, ↓ serum albumin, and relatively higher ratio of fat:muscle tissue (extends fat-soluble drugs)
• older adults have ↑ sensitivity to benzodiazepines and anticholinergic drugs such as hypnotics, tricyclic antidepressants (TCAs), antihistamines, and antipsychotics

** Anticholinergic drugs causes:
- constipation
- urinary retention (esp men w/ BPH)
- blurred vision
- dry mouth
- orthostatic hypotension

American Geriatrics Society has made a list of inappropriate meds for the elderly: Beers Criteria