Geria, Peds

• Gerontology

  The study of aging
• Geriatrics


  Subspecialty of clinical medicine that focuses on care of the aged, normal aging, as well as the unique features of common illnesses in the elderly
• An aged person usually has the same adaptive mechanisms to stress as a younger person


  Adaptations may not be as rapid or as robust
• Age-dependent changes in concentrations of analytes are important in a number of areas of chemistry
• The aging process involves both biochemical and physiological changes

  With increasing age → decrease ability to respond to stress

  Leads to an age-associated increase in the prevalence of pathological conditions
• Total body muscle mass → decreases with age, but the rate and extent of loss have a strong genetic component
• Sarcopenia is the decrease in lean body mass and a decrease in total creatinine production. Serum creatinine → no longer reliable for assessment of renal function in the aged
• Total bone density and mass → decreases in both men and women (more dramatic after menopause)
• • Serum calcitonin → rise with age
• Ionized calcium → remain stable
• PTH levels → increase in post-menopausal women and is associated with changes in bone metabolism
• Atrophic gastritis → increases with a consequent increase in vitamin B12 deficiency from poor absorption
• Achlorhydria → increases

  results in decreased calcium and iron absorption, as well as an increased incidence of bacterial overgrowth in the small intestine
• Albumin levels → decrease → malnutrition → increases → leading to higher mortality rates
• The number of functional glomeruli → decreases → resulting in a decrease in kidney size and weight
• GFR decline and renal blood flow is more reduced → filtration fraction (GFR/renal plasma flow) increases
• Kidney concentrating ability → declines
• EPO → increases with age, and the level of serum renin → decrease
• Renal responsiveness to ANP → decreases, and serum levels of ANP and BNP → increase
• Thymus → shrinks → a decrease in thymosin levels and T-cell function
• B-cell function → slowly declines → cellular and humoral immune responses are less vigorous and slower
• Autoimmune antibody (antinuclear antibody [ANA]) → increase
• Hematopoietic stem cell numbers → decrease
• ACTH and cortisol → typically do not change, though response to stress may be delayed
• Pulsatile secretion of growth hormone → diminishes → resulting in a decrease in lean body mass/fat ratio, as well as loss of overall body mass
• The peak but not the basal levels of melatonin secretion → decrease → contribute to sleep cycle disorders as well as diminished protection from free radicals
• Norepinephrine secretion → increases → contributes to systemic vasoconstriction and decrease in myocardial relaxation
• Epinephrine → remain stable
• Aldosterone → may decline, which can contribute to orthostatic hypotension
• Thyroid hormone → well preserved or slightly increased into very old age
• Insulin secretion → unchanged
• An individual with the genetic predisposition to type II Diabetes Mellitus is more likely to manifest clinical illness with increasing age, body mass index, and lack of exercise
• reduction in gonadal production of estrogen and progesterone and secondary increase in hypothalamic gonadotropin-releasing hormone persist through the remainder of a woman’s life
• Testosterone in men → gradual decrease
• Dehydroepiandrosterone (DHEA), sulfated DHEA, and pregnenolone → all decrease