Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
Physiological fuctions of bone
|
Ridged Support- kyphoscoliosis vs lowerdosis.
Role in locomotion-bipedal motion, points of attachment and leverage for muscles. Ion Reservoir-Ca, Mg, PO stored in bone, tapped when bodies needs not met. |
|
|
structure of bone
|
strong for weight bearing not brittle. lightweight but stiff for locomotion. dynamic architechture for growth, remodleing, repair. Protein matrix-Osteoid. Collogen I, hydroxapetate crystals-Ca,
corical bone-compact bone-long bones, structure trabecular bone-spongy mesh, vertebra |
|
|
Bone Cells
|
Osteoblasts-build bone, respond to PTH and VitD (VDR) lay down collegen
Osteoclasts-catabolis bone, mineral RA, stimulate by mCSF, PTH, VitD. Osteocytes- paly a role in bone maintenance, form syncytia, communication between corical bone and bone surface. |
|
|
Signs of Hypercalcemia
|
CNS: depression, fatigue, stupor, coma, wuscle weakness,
CV, HTN, bradycardia, short QT interval on ECG puritis, polyuria, polydipsia, thirst, renal stone, urinary concentrating defects, dehydration anorecia, nausea, vomiting, constipation, band keratopathy |
|
|
Signs of hypocalcemia
|
tetany, muscle cramping, paresthesias, laryngospasm, seizures, altered mental state
coma, muscle weakness, fatigue, basil gang, brain califications papilledema, cataracts CHF, PROLONGED QT interval on ECG |
|
|
Lab Dx hypercalcemia
|
iCa and serum albumin
PTH, PTHrP, 25OH-D, 1-25 dihydrozy D, eelctrolyes, PO, Alk PO, thyrotropin, Urine Ca and creatinine |
|
|
DDx Hypercalcalcemia
|
1. HPTH--sporadic, MEN1 or 2
2. Variant of HPTH-familial benign hypercalcemia. 3. Cancer-PTHrP tumors, 4. osteolysis 5.Granulomatous disease sarcodosis 6. Renal failure, Drugs |
|
|
Primary vs Secondary Hyperparathyroidism
|
inpatient 90% malignancy
outpatinet 90% Primary hyperparathyriodism |
|
|
Primary vs Secondary Hypoparathyroidism
|
1: post surgery, for thyroid/parathyroid, autoimmune of PTH gland, activating mutation of CaRs in parathyroid glands and kidney.
2. other mechanisms |
|
|
Causes of Vit D deficiency
|
1. subclinical malabsorption, postgasterctomy state, cholestatic liver, panc disease.
2. diet is low in dairy 3. lack of sunlight exposure 4. drugs enhance clearance of 25-D 5. renal function declines gradually with age |
|
|
Osteomalacia
|
hihg alkaline PO is indicative of osteomalacia, deminerilzation of bone.
Vit D deficiency reduces serum Ca and PO, new bone is underminerilized. disease is osteomalacia. bone pain, waddling gait, proximal myopathy. Pseduofractions loosers zones, radiolucent bands on bony surfaces. occur at sites of nutreint arterys on done. High bone turnover, unminerialized bone |
|
|
Rickets
|
growing bony skeleton, Kids
delayed growth, epiphyses, a variety of bony abnormalities. Rachitic rosary, ribs , bowlegged, knock knee. cupping and thinkening of the ephysial growth plates, cortical thinning. |
|
|
Lab features: Primary Hyperparathyroidism
|
high Ca
low PO or nl High PTH high 25 OH-D or nl |
|
|
Lab features: Humoral Hypercalcemia of maligancy
|
high Ca
very low PO Low PTH low 25 OH-D or nl |
|
|
Lab features: Vitamin D deficiency
|
low Ca
nl MG low PO or nl very high PTH low 25 OH-D nl creatinine nl 1,25 OH-d or nl |
|
|
Lab Features: PTH resistance
|
low Ca
nl MG high PO or nl high PTH nl 25 OH-D nl creatinine nl 1,25 OH-d or decreased |
|
|
DDx of Hypomagnesemia
|
excessive loss: EtOH, osmotic diuresis, diuretics, antibotics, drugs, renal tubular wasting
Excessive gastrointestinal loss of Mg: Vomiting, Nasogastric suction, diarrhea, Gastroenterities, Short bowl syndrome, fistulas, malabosorption, malnutrition pancreatitis, primary hyperaldosteronism, diabetes mellitus |
|
|
Lab features: Hypomagnesemia
|
slighty low Ca
low MG nl PO nl, low, slighty, low PTH nl 25 OH-D nl creatinine deacread 1,25 OH-d |
|
|
Pathophysiology of hypomagnesemia
|
common cause of mild hypocalcemia
Alcholism!!! Mg cofactor adenyl cyclase, activated to PTHR stim. No MG, No AC, NO PTHR stim, hypoparathyroidism, hypocalciemia. insuffienct production of 1,25 OH-d |
|
|
Treat Hypercalcemia
|
1. underlying cause
2. surigal removal parathyroid 3. glucocorticoids antagonize VD 4. rehydrate with saline 5. use loop diuretics-calcinerisis 6. block bone resorption 7. calcintonin injections |
|
|
Treat Hypocalcemia
|
1. oral calcium supplments
2. vitamin D metabolite 3. acute-IV Cal-gluconate, IV constant infusion, only if tetany, laryngospasm, bronchospasm |
|
|
Managment of Osteoporosis
|
bisphosphates-alendronate
PTH injections-stim bone formation calictonin excercise, stop smoking, ca supplimentation, vitamin D |
|
|
Bisphosphates
|
Mx of Action:analogs of pryophosphate-inhibits osteroclast function and bone resorption. mimics of hydroxyapatite. osteoclasts senstive then other cells.
alendronate-osteoporosis. fractures decrease, |
|
|
Parathyroid Hormone Injections
|
for osteoporisis. only true anabolic for bone. Stimulated osteoblast bone formation.
in 21 mo trail..decreased incidence of vertebral fractures. |
|
|
Calcitonin
|
for osteoporosis, cannot use orally,
sometimes for hypercaliciemia inhibits osteoclast actions. |
