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95% asymptomatic (M:F ratio = 2:1)—typically older men
It is a bone remodelling disorder leading to abnormal enlarged sections of bone
Symptoms may include joint pain and stiffness (e.g. hips, knees); bone pain (usually spine); deformity; headache; deafness (compression neuropathy)
Bone pain is typically deep and aching: may be worse at night
Signs may include deformity, enlarged skull—‘hats don’t fit anymore’, bowing of tibia, waddling gait
Bones most commonly affected (in order) are pelvis, femur, skull, tibia, vertebrae; increased risk of osteosarcoma
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Raised serum alkaline phosphatase (often very high >1000 U/L)
Note: Calcium and phosphate normal
Plain X-ray: dense expanded bone best seen in skull and pelvis
Note: Can mimic prostatic secondaries so every male Pagetic patient should have PR and PSA test
Bone isotopic scans: useful in locating specific areas
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Treatment The two major goals are relief of pain and prevention of long-term complication (e.g. deafness, deformities).
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Localised and asymptomatic disease requires no treatment.
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Three groups of drugs currently available:
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the bisphosphonates (i.e. etidronate, pamidronate, alendronate, tiludronate)—first line but serum Ca and vitamin D and eGFR must be OK
the calcitonins (salmon, porcine, human)—used if bisphosphonates contraindicated (e.g. adverse effects)
various antineoplastic agents (e.g. mithramycin)
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Bisphosphonates are first-line agents (oral agents taken on an empty stomach)—one of:
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alendronate 40 mg (o) daily for 6 mths (oesophagitis can be problematic)
pamidronate disodium 60 mg IV infused over 4 hrs (usually preferred option); repeated doses may rarely be required according to disease activity
risedronate 30 mg (o) daily for 2 mths
tiludronate 400 mg (o) daily for 3 mths
zoledronic acid 5 mg IV, over at least 15 mins once yearly