Metabolic Bone Disease Flashcards
Bone matrix
Made of collagen support surrounded by hydroxyapatite for stregnth
Osteoproroiss
Osteomalacia/rickett’s
Paget’s overview
Formation and resorption
Decreased formation, increased resorption…increase due to age/hormonla
Decreased ofrmation, no resorption change…decreased mineralization of collagen matrix
Increased formation but nbigger increased resorption…local overactivation of osteoclasts
Bone strenght is
Quantity of bone plus quality of architecture
T score and Z score
T score compares to white female
Z score compares to cohort
Osteoporosis pathophys
Loss of bone strenght due to altered uqualith and quantity
Loss of collagen support and hydroxyapatite
Imbalance betwen turnover and formation
Osteoporosis types
Postmenopausla or primrary - aging/hormonal
Secondary -younger
Notable osteopororiss risk factors
Female Low BW Excess alcohol low Vit D or calcium Cig
Osteoporosis signs and symptoms
Asymptomatic until fragility fracture occurs
Normall thoracic/lumbar spine of hip
Diagnosis of osteoporosis
Post menopausal women or men over 50
T score
Osteopenia diagnosis
Postmeno women or men over 50
T scroe between -1 and -2.5
Osteomalacia and rickets
Impact mineralization of the collagen matrix of bone
Osteomalacia only in adults and involves cortical only
Rickets in children and involves cortical bone, growth plates ,and cartilage
Osteomalacia vs. porosis
Malacia - normal matrix with decreased mineralization
Porosis - decreased matrix and mineraliaation
Osteomalacia and ricket presentation
Bone and muscle weakness, tenderness, fracture,s wddling
Osteomalacia diagnostic eval
DEXA may be normal or show decreased B
Osteomalacia and ricket pathophys
Abnormalities in Vit D and calcium
Abnormalitlies in phopshorus
Abnormalities in enzymes needed to mineralize bone (alkaline phosphatase)
Abnormailites in Vit D
Vit D deficiency
Inability to produce inactive form - liver dz
Antiepileptics
Inability to convert to active - chronic kidney dz or dependent rickets type 1
Osteomalacia and rickets phosphorus abnormalities
Decreased dietary
Decreased absorption
Renal phosphate wasting (tubular defect, hypophosphatemia, oncogenic osteomalacia, tenofovir)
Familial hypophosphatemia
Defect in FGF 23 causing renal phsophate wwasting
Xlinked most common
Hypopohios, slowgrwoth, enthesopathy, dental carries
Tx with calcitrol and phosphorus
Osteogenic osteomalacia
Tumors that produce FGF23
Low phosphorus and osteomalacia
Remove tumor
Hypoposphatasia
Decreased alkaline phosphatasia
Pyrophosphate deposits and inhibits mineralization
Enzyme replacemrnt or BMT
Paget’s dz pathogenesis
Abnormal osteoclasts activity resulting in excessive bone remodeling
Affects speciic areas
Overgrowth in some and under in other
Paget’s clinical presentation
Arthritis, bleeding, bone pain
Asymptomatic elevation of alkalaine phosphate or incidental rediographic finding**
Paget’s most common bones
Pelvis, lumbar spine, femur
Diagnositc eval of Paget’s
Elevation in alkaline phosphatase
X-ray
Bone scan
Paget’s dz hallmarks
Osteoporosis circumscripta
Blade of grass sign
Cotton wool skull
Diagnosis of Paget’s
Radiographic evidecne with an elevated alkaline phosphatase
Bone biopsy only need if evidence of osteosarcoma
Indication for tx Paget’s
Symptomatic OR
asympto with active dz and a lesion
Paget’s tx
Bisphosphonates - 1st line bc inhibit bone resoprtion by osteoclasts
Calcitrol - 2nd line
Surgery
Complications of Paget’s
Hyperparathyroidism, osteosarcoma,
