Clinical Chemistry and the Geriatric patient

•Aging means to grow older•Several physiological changes occur as people

age•These changes are gradual•Deterioration results from time-dependent ,•irreversible changes•These changes will be reflected in clinical

laboratory test results

•Life expectancy is increasing, for persons born in 1900(47years) to (77years) for persons born in 2001

•This gain is due to improved sanitation, better medical care and increased use of preventive health

services•Geriatrics is the branch of health care concerned

with the care of the aged, including physiological, pathological, psychological, economic and

sociological problems

Gerontology is the study of the aging processThe demand on the health care system by geriatric patients is different from that of the rest of the

populationHealth care will need to shift its emphasis to meet

the need of chronically illAs the population ages, increase in chronic

diseases such as cancer, arthritis, hypertension and diabetes are expected

•This means more physician office visits, hospital stays and laboratory tests

•The clinical laboratory professional must treat the patient with dignity and respect. They must be

aware of special considerations regarding the collection of blood samples, development of reference intervals, effect of medications on

chemistry results .•They must understand the effects of aging on

laboratory values

Current Theories of Aging

•1 -Random Genetic Damage•-Mutation•-Background Radiation Damage e.g ultraviolet rays

which may cause chromosome or DNA damage•-errors in chromosomal translocation or

transcription•2 -glycation of Proteins•Interfere with both cell structure and function

•3 -Developmental Theories•-Immune and Neuroendocrine System•.. Immune system declines with age e.g thymic atrophy,

reduction of B and T cell population, decreased response to neoantigens, misfolding of proteins which may lead to amyloidosis

•4 -Genetically Programmed Theory•defects in apoptosis..•5-Free Radicals(OH, O2, NO…)• Cause damage to cells•N.B delay of aging in rodents was accomplished by calorie

restriction

Diseases and Disorders commonly associated With Aging

•Atherosclerosis( e.g myocardial infarct, renal disease, stroke)

CancerDiabetes mellitus

HyperparathyroidismHyperthyroidismHypothyroidism

Monoclonal gammopathies(e.g multiple myeloma)osteoporosis

The Top Ten Leading Causes of Death (Age 65 and Older)

•heart disease•Cancer•Stroke•Chronic lower respiratory disease•Accidental death due to unintentional injury•Diabetes•Alzheimer disease•Influenza or pneumonia•Nephritis, nephrotic syndrome or nephrosis•Septicemia

Changes in Selected Clinical Chemistry Analytes With Age

•A- Increase•GGT•ALP(women)•Alpa-1 antitrypsin•Amylase•AST•BUN•CK•Gammma globulin•Fasting Glucose•HDL

Increase

•Inorganic Phosphate•LDH•PCO2•K•Total Cholesterol•Triacylglycerol•TSH•Uric Acids

Decrease•Albumin•Aldosterone•Bilirubin•Creatinine Clearance•DHEA•Growth Hormone•PO2•T3•Total Protein•Transferrinss

Unchanged

•Chloride•Cortisol•Free T4•Haptoglobin•Insulin(fasting)•PH or Slight decrease•Na•T4 or Slight decrease•Thyroid-binding globuli(TBG)

Endocrine Function Changes

•Changes in the production of hormones by sex organs, thyroid, pituitary and adrenal glands

•The most notable changes relate to the gonadal and thyroid hormones

•A decrease in the gonadal production of estrogen in women(menopause) and of testosterone in

men(andropause)•The adrenal production of

dehydroepiandrosterone(DHEA) and DHEA sulfate(adrenopause)

•Decrease in the growth hormone-insulin-like growth factor(IGF) axis(somatopause)

•Hormone replacement regimens are being developed as a strategy to delay or prevent some of the

consequences of aging•Dysregulation of apoptosis may be the cause of

diseases such as cancer and neurodegenerative disorders(e.g Alzheimer and Parkinson diseases)

•The major consequences of estrogen deficiency are osteoporosis and CHD.

•Major risk factors of osteoporosis include diet, inactive life style, genetic predisposition,

smoking, endocrine disturbances and medications

•The greatest problem secondary to osteoporosis is hip fracture

•An association between hypovitaminosis D and secondary hyperparathyroidism and osteoporotic changes in the elderly

•The prevelance of hypertension also increases with age, about 60% of people older than 60

years having the condition.•Causes include increased peripheral resistance

due to atherosclerosis, chronic renal and endocrine disorders and multiple medications.

•There is also a decline in the efficiency of homeostatic regulation.s

•Diabetes mellitus and insulin resistance increase with aging .

•Consequences of D.M such as retinopathy, nephropathy and CVD also increase

•Renal function changes as indicated by kidney function tests is common in elderly.

•Hepatic function disorders are observed in elderly.

Pulmonary Function and Electrolyte Changes

•PO2 decreases•PCO2 increases•Na/Cl no changes•K slight increase•Respiratory-related diseases are prevalent in

elderly people.•Diseases include chronic bronchitis, chronic

obsrtuctive pulmonary disease, neoplasia, lung infections particularly T.B and pneumonia

Cardiovascular and Lipid Changes

•Atherosclerosis develops slowly followed by hypertension, hemorrhage, thrombosis, stroke

and CHD•Hyperlipidemia plays major role in

atherosclerotic process and risk for CHD•Cholesterol, triglyceride, HDL levels increase

with aging

Enzymes

•The following enzymes show increased activity:

•AST•ALP•GGT•CK•LDH•Amylase

Establishing Reference Intervals for the Elderly

•It is difficult to establish RI for the elderly due to differences in physiological and pathological

condition of each individual, however the following factors should be considered when

interpreting clinical laboratory results:•Exercise, Medications, Mobility, Nutritional

status, personal habits, Alcohol use, Smoking, Chronic disorders, trauma………and special

conditions