Osteoectasia familial
Overview
Familial osteoectasia (juvenile Paget disease, hyperostosis corticalis deformans juvenilis, chronic congenital idiopathic hyperphosphatasemia) is a familial disorder that manifests early in life with a large head due to a extremely thick calvaria with islands of increased none density.
Symptoms
* Blue sclerae * Deafness * Growth deficiency * Enlarged bone ends * Broadened bone shafts
Causes
The disease occurs worldwide, but is more common in Europe, Australia, and New Zealand, where it’s seen in up to 5% of the elderly population. Although its exact cause is unknown, one theory holds that early viral infection causes a dormant skeletal infection that erupts many years later as Paget’s disease. Genetic factors are also suspected.
Diagnosis
X-rays taken before overt symptoms develop show increased bone expansion and density. A bone scan, which is more sensitive than X-rays, clearly shows early pagetic lesions (radioisotope collects around areas of active disease). Computed tomography scan or magnetic resonance imaging shows extra bony extension if sarcomatous degeneration occurs. Bone biopsy reveals characteristic mosaic pattern. Other laboratory findings include: ❑ elevated serum alkaline phosphatase levels (an index of osteoblastic activity and bone formation) ❑ elevated serum calcium. Increasing use of routine chemistry screens (including serum alkaline phosphatase) is making early diagnosis more common. Serum osteocalcin and N-telopeptide are usually increased.
Treatment
Primary treatment consists of drug therapy and includes one of the following: ❑ Calcitonin (subcutaneously or intranasally) is used to retard bone resorption (which relieves bone lesions) and reduce levels of serum alkaline phosphate and urinary hydroxyproline secretion. Although calcitonin therapy requires long-term maintenance, improvement is noticeable after the first few weeks of treatment. ❑ Bisphosphonates, such as etidronate, alendronate, pamidronate, tiludronate, and risedronate, produce rapid reduction in bone turnover and relieve pain. They also reduce serum alkaline phosphate and urinary hydroxyproline secretion. Therapy produces noticeable improvement after 1 to 3 months. ❑ Plicamycin, a cytotoxic antibiotic, is used to decrease calcium, urinary hydroxyproline, and serum alkaline phosphatase. It produces remission of symptoms within 2 weeks and biochemical improvement in 1 to 2 months. Plicamycin is used to control the disease and is reserved for severe cases with neurologic compromise and for those resistant to other therapies. However, it may destroy platelets or compromise renal function. Orthopedic surgery is used to correct specific deformities in severe cases, reduce or prevent pathologic fractures, correct secondary deformities, or relieve neurologic impairment. Joint replacement is difficult because bonding material (methyl methacrylate) doesn’t set properly on pagetic bone. Other treatment varies according to symptoms. Analgesics or nonsteroidal anti-inflammatory drugs may be given to control pain.