Osteoporosis (Week 5--Pregler) Flashcards Preview

Block 3: GI, Endocrine, Reproductive > Osteoporosis (Week 5--Pregler) > Flashcards

Flashcards in Osteoporosis (Week 5--Pregler) Deck (15):
1


Osteoporosis


Low bone mass, microarchitectural deterioration of bone tissue

Resorption exceeds bone formation but ratio of mineral to matrix remains normal

Risk factors: caucasian or Asian, female, advanced age, hx fracture in first deg relative, low BMI, early menopause, long premenopausal amenorrhea (can be caused by pregnancy/breast feeding), cigarette smoking, alcoholism, low Ca2+ intake, inactive lifestyle

Over 8 million women and 2 million men in US have osteoporosis

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Facts about osteoporosis

 

Over 1/2 all women in US will have osteoporotic fracture in their lifetime

If over 50 and break hip, 24% mortality within a year and 1/3 must go to nursing homes

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Osteoblasts


Lay down bone matrix

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Osteoclasts


Resorb bone, form lacune

5


Two types of bone


1) Trabecular: axial, more active metabolically, first site of osteoporosis

2) Cortical: peripheral

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What regulates bone formation and remodeling?


Estrogens/androgens

Vitamin D

Parathyroid hormone (PTH)

Local growth factors

Steroid hormones

Thyroid hormones

Illnesses: hematologic disorders, rheumatoid arthritis, Type 1 DM, inherited disorders

Drugs interfere w/bone formation: immunosuppressants, corticosteroids, excess thyroid hormone, anticonvulsants (induce CYP450 and alter vitamin D metabolism)

7


Endocrine glands


Produce peptides, steroids and amines that control metabolism, growth, reproduction, and fluid and electrolyte balance

Adrenal medulla (NE, EPI)

Pancreas (insulin, glucagon)

Kidney (renin, 1,25 vitamin D)

Parathyroid glands (PTH)

Hypothalamic-pituitary-end organ axis

Corpus luteum/placenta

8


What body functions and behaviors does the hypothalamus regulate?


Body temperature, food intake, water balance, stress response, reproduction and social interaction, 5 senses

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Which peptides does the hypothalamus release that act in the anterior pituitary?


Thyrotropin RH

Corticotropin RH

Gonadotropin RH

Growth hormone RH

Prolactin-inhibiting factor (dopamine)

10

Which peptides does the hypothalamus release (via neurons) that act in the posterior pituitary?


Oxytocin

Vasopressin (ADH)

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Which peptides does the anterior pituitary release?

FSH

LH

ACTH

TSH

Prolactin

GH

(FLAT PeG)

12


What are the end-endocrine organ effects?


Adrenal cortex: glucocorticoids (gluconeogenesis, immunomodulation, vascular responsiveness to catecholamines), mineralocorticoids, adrenal androgens

Ovaries and testes: reproduction

Thyroid gland: skeletal growth, O2 consumption, nutrient utilization

13


What are some systemic and non-endocrine organ effects?


GH: protein synthesis, growth

Prolactin: milk production and secretion

14


DEXA (dual-energy x-ray absorptiometry) scan


Used to determine bone density

Scores reported relative to "young normals" or age-matched controls

15


Treatment for osteoporosis


Bisphosphonates

Teriparatide (PTH in short bursts)

Exercise

Ca2+ and Vitamin D3

 

Thiazide diuretics (has not been a clinical trial because thiazides are generic and no drug company to fund study, but thiazides help retain Ca2+, so when you give thiazide for HTN, just hope it has good side effect for osteoporosis!)