60 yrs old male with bony abnormality at upper tibia associated with sensori neural hearing loss. On laboratory examination serum alkaline phosphatase levels are (440 mU/1) elevated and serum Ca++ and PO4– are normal. Skeletal survey shows ivory veebrae and cotton wool spots in x-ray skull. Diagnosis is :
Correct Answer: >Paget disease
Description: Paget disease The clinical and lab. findings in this elderly male along with characteristic x-ray findings are indicative of Paget ds. Paget disease Paget disease, a relatively common bone disorder, is a chronic progressive disturbance in bone metabolism that primarily effects older persons. Male > Females (3 : 2) Pathology The basic pathological process in Paget disease involves the balance between hone resorption and new bone formation (Osteoclastic and osteoblastic bone activity) The disease passes through three stages : 1st - Oeolytic or hot phase - the pathological process is initiated by overactive osteoclastic bone resorption. IInd - Intermediatior Mixed phase - Osteoclastic hone resorption is followed by compensatory increase in osteoblastic new bone formation. 111rd - Cool Phase - this is sclerotic phase in which the osteoblastic activity is greatly in excess of osteoclastic resorption, leading to marked thickening of bony trabeculae and coex. New pagetic bone is structurally disorganized and more susceptible to bowing and fracture. Although most patients are asymptomatic, a variety of symptoms and complications may result directly from bony involvement or secondarily from the expansion of bone and subsequent compression of neural tissue (sensorineural hearing loss in this patient due to compression of choclear nerve from temporal bone involvement) Biochemically the increase in osteoblastic activity is reflected in elevated levels of serum alkaline phosphatase which can rise to extremely high values. The increase in osteoclastic bone resorption is reflected in high urinary levels of hydroxyproline, which is formed as a result of collagen breakdown. Distribution The distribution of the disease varies from monostotic involvement to widespread disease. Pelvis is the most commonly involved bone followed by femur, skull, tibia, veebrae. Clinical manifestations Asymptomatic patients are often diagnosed by discovery of an elevated alkaline phosphatase level on routine blood chemistry or from an abnormality on a skeletal radiograph obtained for other reasons. Pain is the most common presenting symptom. It occurs due to increased bony vascularity, expanding lytic lesions, fractures, bowing or other deformities of the extremities. Bowing of the femur or tibia causes gait abnormalities and abnormal mechanical stresses with secondary osteoahritis of the hip or knee joints. Back pain results due to enlarged pagetic veebrae, veebral compression fractures, spinal stenosis or kyphosis. Skull involvement may cause headache, symmetric or assymmetric enlargement of the parietal or frontal bones (frontal bossing) and increased head size Cranial expansion may narrow cranial foramine and cause neurological complications including hearing loss from choclear nerve damage from temporal bone involvement, cranial nerve palsies, and softening of the base of the skull (platybasia) and the risk of brainstem compression. Pagetic involvement of the facial bones may cause facial deformities, loss of teeth or other dental conditions. Other complications are - Fractures (most common complication) - Neoplastic transformation: development of bone sarcoma (most commonly osteosarcoma) is a rare but serious complication of Paget disease. - Cardiovascular complications : The extensive aeriovenous shunting and marked increase in blood flow through the vascular pagetic bone leads to a high output state and cardiac enlargement. Diagnosis The diagnosis may be suggested on clinical examination by the enlarged skull with frontal bossing, bowing of an extremity, or sho stature with simian posturing. A warm extremity on palpation may suggest an underlying pagetic bone Radiological findings Radiographic features depend on the stage of the disorder In the early osteolytic phase - active bone resorption is evident as a radioluscent wedged area in long bones termed as 'candle flame' or 'blade of grass'. - in the flat bones such as the calvarium or the iliac bone, purely osteolytic lesion is noted, k/a osteoporosis circumscripta Later phases of new bone formation - Bone remodelling appears radiographically as thickening of the coex, coarse trabeculation and enlargement or expansion of an entire bone or area of a long bone. - Veebral coical thickening of the superior and inferior end plates creates a 'picture frame veebra'. - Diffuse radiodense enlargement of a veebra is referred to as 'ivory veebra'. - Skull x ray shows focal patchy densities - cotton ball appearance, which is quite characteristic of Paget disease. - Pelvic radiograph demonstrate disruption or fusion of the sacro-iliac joints and softening with protrusio acetabuli - Long bones reveal bowing deformities and typical pagetic changes of coical thickening and expansion and areas of lucency and sclerosis. Biochemical findings - T alkaline phosphatase levels (indicative of osteoblastic activity, marker of bone (formation) - T Urinary hydroxyproline levels (marker of bone resorption) [The parallel rise in serum alkaline phosphatase and urinary hydroxyproline levels confirm bone formation and resorption in Paget disease} The degree of bone marker elevation reflects the extent and severity of the disease. - Urinary and serum deoxypyridinoline N-telopeptide, and C-telopeptide levels are products of degradation and are more specific for bone resorption than hydroxyproline. - Serum calcium and phosphate levels are normal Treatment - Paget disease is treated with drugs which suppress the very high rates of bone resorption and secondarily decrease the high rates of bone formation Bisphosphonates - Etidronate - A lendronare - Tiludronate - Risedronate - Pamidronate Calcitonin
Category:
Surgery
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