Abstract
Introduction: Paget’s disease of the bone is characterized by excessive osteoclastic bone resorption followed by formation of disorganized bone; which is often focal. Bone pain and deformities are common features and it often leads to complications such as pathological fractures, deafness or neurologic deficits. Elevated bone turnover markers and alkaline phosphatase reflect ongoing exaggerated bone resorption and osteoblastic activity. We present an unusual scenario of post-menopausal osteoporosis and Paget’s disease occurring in the same patient.
Clinical Case: 86-year-old female with history of Type 2 Diabetes Mellitus, Hypertension,
Hypothyroidism, degenerative joint disease of lumbar spine with prior interbody fusion and laminectomy was referred to our clinic by Orthopedics for evaluation of newly diagnosed Paget’s disease. 2 months ago, she noticed severe right hip pain limiting daily activities. She denied any history of falls, fractures or family history of Paget’s. Physical exam was notable for tenderness to right sacro-iliac joint and right femoral trochanteric region. Work up included MRI of Lumbar spine and Pelvis, Pelvis X-ray, DEXA scan and routine blood work.
Interestingly, her DEXA scan showed T score of +2.9 in Right hip and -3.1 in Left hip. On Pelvis X-ray cortical thickening, coarse trabecula and osteoarthritic changes were noted in right femur and hip, consistent with Paget’s disease. Left femur showed strikingly thinner cortices compared to the right, due to underlying osteoporosis. MRI of lumbar spine and pelvis was consistent with polyostotic Paget’s involving L3-L5, Sacrum and Right femur. Nuclear bone scan showed areas of uptake including anterior calvarium, lumbar spine, right hip, right femur, 8th rib, left mid tibia and 1st metatarsal of left foot. Since the distribution of uptake seemed atypical for Paget’s, a skeletal survey was obtained which was negative for bone lesions suggestive of malignancy.
Laboratory testing revealed serum calcium 9.8mg/dL(8.4–10.2), 25-Hydroxy Vitamin D 30ng/dL(20–30), PTH 45.6pg/mL (15–65), Alkaline Phosphatase 370U/L (35–104), Procollagen I intact N-terminal 516mcg/L (16–96) and N-Terminal Telopeptide (NTX) 126.4 nM BCE (6.2–19).
Patient received one dose of IV Zoledronic acid with modest improvement in hip and lower back pain. She continues to take Calcium carbonate 600mg twice daily and vitamin D3 1000IU once daily. We plan to see her in follow up in 3 months with repeat levels bone turnover markers.
Conclusion: This is a unique case of Paget’s disease and osteoporosis, two very different diseases of metabolic bone disorder spectrum found in one patient. Treatment of Paget’s disease is indicated for pain reduction, prevention of fractures and deformities and to prevent disease progression in weight bearing areas. Bisphosphonates can target pathology of both diseases by reducing osteoclastic bone resorption.
Bone turnover markers (BTMs) in the synovial fluid in the patients with osteoarthritis correlates with the serum level of BTMs though some patients with osteoporosis exhibit mismatched increase in bone resorption activity in synovial fluid
