Paget's Disease Flashcards
second most common disease of bones after osteoporosis in older persons
Paget’s disease
when are people typically diagnosed with paget’s disease
diagnosed after bone lesions
discovered on imagine or high levels of serum alkaline phosphatase
discovered incidentally
which bones does paget’s MC affect
bones of axial skeleton
vertebrae, pelvis, demur, sacrum, skull
paget’s disease etiology
unknown
believed to be genetic or viral factors
paget’s epidemiology
affects men more frequently than women
increasing incidence with age
caucasians, northern latitudes
high anglo-waxen populations
phases of paget’s
- lytic (rapid bone reabsorption)
- mixed lytic and plastic phase (bone reabsorption + bad bone creation)
- sclerotic (abnormal bone formation)
lytic phase
first phase
increased number and activity of osteoclasts
9x reabsorptive rate of normal bone
osteoclasts in paget’s
much larger than normal osteoclasts
7 times more resorptive capacity or normal
lytic/blastic phase of paget’s
second phase
large numbers of normal osteoblasts act to rebuild bone as it is breaking down
produces bone matrix rapidly and haphazardly
“mosaic pattern”
bone marrow is replaced by fibrous tissue and increased number of blood vessels in the bone
sclerotic phase
bone reabsorption ceases but abnormal formation continues leading to hard, dense vascular mosaic bone
bone is weaker than normal adult bone
pathophysiology of paget’s
bone breakdown and bone rebuilding (shotty rebuild)
development of new sites of disease occurs uncommonly
predilection for axial skeleton and long bones
bony manifestations of paget’s
increased risk of fracture
bony enlargement of the skull and face
bowing go long bones and periarticular osteoarthritis
vertebral enlargement and kyphosis
nerve entrapment
bone pain
less common manifestations of paget
increased bleeding w/bone fractures
vascular steal (less blood)
CV
RARE but possible progression to osteosarcoma
clinical manifestations of paget’s
asymptomatic and disease is found incidentally
most frequent symptom is bone pain (dull, constant, boring, deep)
prone to fracture
lab abnormalities of paget’s
serum calcium levels are normal in untreated pt
elevated serum alkaline phosphatase and uric acid
secondary hyperparathyroidism (bc cant take in enough Ca)
radiologic diagnosis of Paget’s
characteristics seen on X-rays
bone scan is study of choice (extent of disease)
CT/MRI (diagnosis of malignant transformation)
pharmacologic treatment is indicated in
patients with symptomatic disease and in asymptomatic patients with high risk of complications
pharmacologic treatment of choice
cyclic doses of oral bisphosphonates in fairly high doses
bisphosphates used
alendronate/Fosamax
zoledronic acid (zometa) IV- most effective
etidronate - least effective
bisphosphates MOA
analogues of inorganic pyrophosphate and bind to hydroxyapatite in bone matrix
inhibits dissolution of crystals by osteoclasts
MAKE BONE
administration of bisphosphates
patient direction
poorly absorbed from GI tract
should be taken 2 hours before or after meals WITH NO calcium
taken with full 8oz of water
pt must sit or stand upright for 30 min
ADRs to bisphosphate
hypocalcemia (should take vitamin D and calcium)
urticaria/angioedema
esophageal ulceration
osteonecrosis of jaw
goals of bisphosphate therapy
success of treatment is measured by normalization of alkaline phosphatase levels
check for alkaline phosphatase remission every 2-3 months and when it falls start them again
prognosis of paget
generally favorable
younger age of diagnosis is poorest prognosis
rapid institution of effective tx reduces likelihood of complications
