NR 601 MIDTERM STUDY GUIDE REVIEW
Chapter 1: Changes with Aging - Notes
Fundamental Considerations
- Recognize that presenting features of disease/illness may be different and having a greater awareness of
the impact of chronic illness on the patient.
- Perspective is different than with younger adults.
Physiological Changes with Aging
- The clinician must be aware that all the systems interact an, in doing so, can increase the older
person’s vulnerability to illness/disease.
- During the clinical decision-making process, the clinician knowledgeable about physiological changes with
aging will be less likely to undertreat a treatable condition. -Example- Use the diagnostic process to differentiate
the more benign seborrheic keratosis from actinic keratosis.
- Be informed; do not attribute a finding to the aging process alone. The elder may conclude there is no point
in changing behavior, because the process is inevitable.
- Three primary points:
1) There is a reduced physiological reserve of most body systems, particularly cardiac, respiratory, and renal.
2) There are reduced homeostatic mechanisms that fail to adjust regulatory systems such as temperature
control and fluid and electrolyte balance.
3) There is impaired immunological function: infection risk is greater, and autoimmune diseases are
more prevalent.
Laboratory Values in Older Adults
- Many factors can influence lab value interpretation in the elderly, including the physiological changes with
aging, the prevalence of chronic disease, changes in nutritional and fluid intake, lifestyle (including activity), and
the medications taken.
- Reference ranges therefore may be preferable. Reference ranges or intervals, such as age, sex, or race can be
defined demographically. For example, the reference range for older adults might be the intervals within which
95% of persons over age 70 fall.
- Further defined physiologically (fasting or activity status) or pharmacologically (medication, tobacco or ETOH use).
- Biochemical individuality is of particular importance in detecting asymptomatic abnormalities in older adults.
Significant homeostatic disturbances in the same individual may be detected through serial laboratory tests,
even though all individual test results may lie within normal limits of the reference interval for the entire group.
- The clinician must determine whether a value obtained reflects a normal aging change, a disease, or the
potential for disease.
- Misinterpretation of an abnormal lab value as an aging change can lead to underdiagnosis and undertreatment in
other (anemia or UTI) and overdiagnosis and overtreatment in others (hyperglycemia or asymptomatic
bacteriuria).
- At times, the result of a lab value may be within the appropriate reference range yet indicate pathology for
the older adult.
- Calculation of creatinine clearance is important in the estimation of renal function.
- Reduced renal function, particularly GFR, affects clearance of many drugs, and creat clearance provides an
index of renal function for use in choosing doses of renally eliminated or nephrotoxic drugs (such as dig, H2
blocker, lithium, and water soluble antibiotics)
- The Modiciation of Diet in Renal Disease (MDRD) and Cockcroft-Gault equations both provide useful estimates
of the GFR.
- Any risks involved in lab testing must be considered with respect to the patient’s clinical condition and weighed
