Nonmalignant complications of Paget's disease

Effects of Bisphosphonate Treatment on Circulating Lipid and Glucose Levels in Patients with Metabolic Bone Disorders

Bisphosphonates are the first-choice treatment of osteoporosis and Paget's disease of bone. Among the bisphosphonates, the non-amino-bisphosphonates, such as clodronic acid, are intracellular converted into toxic analogues of ATP and induce cellular apoptosis whereas the amino-bisphosphonates, such as zoledronic acid, inhibit the farnesyl-diphosphate-synthase, an enzyme of the mevalonate pathway. This pathway regulates cholesterol and glucose homeostasis and is a target for statins. In this retrospective cohort study, we evaluated the effects of an intravenous infusion of zoledronic acid (5 mg) or clodronic acid (1500 mg) on blood lipid (i.e. total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol and triglycerides) and glucose levels in patients with osteoporosis and Paget's disease of bone. All patients were evaluated before, 1 and 6 months after bisphosphonate treatment. Pagetic and osteoporotic patients treated with zoledronic acid showed a significant reduction in glucose and atherogenic lipids during follow-up whereas these phenomena were not observed after clodronic treatment. The effect on circulating lipid levels was similar in naïve and re-treated Pagetic patients. Zoledronic acid treatment was associated with a reduction in blood glucose and atherogenic lipids in patients with metabolic bone disorders. The extent of change was similar to that obtained with the regular assumption of a low-intensity statin. Further studies are warranted to better evaluate the clinical implications of these observations.

Polymorphisms in genes implicated in base excision repair (BER) pathway are associated with susceptibility to Paget's disease of bone

Paget's disease of bone (PDB) is a chronic bone metabolic disorder. Currently, PDB is the second most frequent bone disorder. PDB is a focal disorder affecting the skeleton segmentally but the cause of which is unknown. It has been hypothesised that somatic mutations could be responsible for the mosaicism described in PDB patients. Therefore, our hypothesis is that defective response to DNA damage may lead to somatic mutations favouring an increased risk of PDB. So that we have analysed polymorphisms in DNA repair genes involved in the BER, NER and DSBR pathways in order to evaluate the role of these variants in modulating PDB risk. We found statistically significant differences in genotypic and allelic distribution for polymorphisms in genes implicated in the BER pathway. Our results showed that carrying the allele T of XRCC1 rs1799782 polymorphism and the allele G of APEX rs1130409 polymorphism increased the risk of developing PDB. These polymorphisms could cause a lower DNA repair efficiency and this might lead to local somatic mutations favouring bone metabolic alterations characteristic of PDB. This is the first report showing an association between polymorphism in genes implicated in the BER pathway with PDB.

Clinical and Genetic Advances in Paget's Disease of Bone: a Review

Paget’s disease of bone (PDB) is the second most common metabolic bone disorder, after osteoporosis. It is characterised by focal areas of increased and disorganised bone turnover, coupled with increased bone formation. This disease usually appears in the late stages of life, being slightly more frequent in men than in women. It has been reported worldwide, but primarily affects individuals of British descent. Majority of PDB patients are asymptomatic, but clinical manifestations include pain, bone deformity and complications, like pathological fractures and deafness. The causes of the disease are poorly understood and it is considered as a complex trait, combining genetic predisposition with environmental factors. Linkage analysis identified SQSTM1, at chromosome 5q35, as directly related to the disease. A number of mutations in this gene have been reported, pP392L being the most common variant among different populations. Most of these variants affect the ubiquitin-associated (UBA) domain of the protein, which is involved in autophagy processes. Genome-wide association studies enlarged the number of loci associated with PDB, and further fine-mapping studies, combined with functional analysis, identified OPTN and RIN3 as causal genes for Paget’s disease. A combination of risk alleles identified by genome-wide association studies led to the development of a score to predict disease severity, which could improve the management of the disease. Further studies need to be conducted to elucidate other important aspects of the trait, such as its focal nature and the epidemiological changes found in some populations. In this review, we summarize the clinical characteristics of the disease and the latest genetic advances to identify susceptibility genes. We also list current available treatments and prospective options.

Paget's Disease Mimicking Bone Metastasis in a Patient with Neuroendocrine Tumor on 68Ga-DOTANOC PET/CT

Somatostatin (SST) is a neuropeptide present in neurons, endocrine cells, and a wide range of neuroendocrine tumors (NETs). ⁶⁸Ga-DOTATOC, ⁶⁸Ga-DOTANOC, and ⁶⁸Ga-DOTATATE are current SST analogues used for PET/CT which bind to SST receptors expressed in NETs. These SST analogues have been used successfully for diagnosis of SST-expressing tumors with a more sensitive detection technique than conventional scintigraphy. However, there is a lack of clinical data on the differentiation between NETs and other malignant tumors or benign pathological conditions. Here, we report a case of Paget’s disease mimicking bone metastasis of NET on PET/CT due to increased ⁶⁸Ga-DOTANOC uptake and review examples of similar cases in the literature.

Diagnosis and management of Paget's disease of bone

OBJECTIVE

To conduct a literature review on the diagnosis and management of Paget's disease of bone.

MATERIALS AND METHODS

This scientific statement was generated by a request from the Brazilian Medical Association (AMB) to the Brazilian Society of Endocrinology and Metabolism (SBEM) as part of its Clinical Practice Guidelines program. Articles were identified by searching in PubMed and Cochrane databases as well as abstracts presented at the Endocrine Society, Brazilian Society for Endocrinology Annual Meetings and the American Society for Bone and Mineral Research Annual Meeting during the last 5 years. Grading quality of evidence and strength of recommendation were adapted from the first report of the Oxford Centre for Evidence-based Medicine. All grades of recommendation, including "D", are based on scientific evidence. The differences between A, B, C and D, are due exclusively to the methods employed in generating evidence.

CONCLUSION

We present a scientific statement on Paget's disease of bone providing the level of evidence and the degree of recommendation regarding causes, clinical presentation as well as surgical and medical treatment.

Paget's disease of bone

Paget's disease is an osteoclastic-mediated disorder of bone that results in abnormal bone resorption associated with inadequate remodeling that leads to mechanically weakened bone. Demonstrating variable geographic prevalence, it is becoming less frequent and age of onset is lengthening in areas of once high prevalence prior to the institution of effective medical therapies, suggesting its etiology involves both environmental as well as genetic factors. Insights into its pathophysiology are helping to clarify other inherited osteolytic disorders of bone by providing additional insights into related cellular processes.

Diagnosis and treatment of Paget's disease of bone: a mini-review

Paget's disease of bone (PDB) is a chronic progressive disorder of bone metabolism that may go undetected for many years, and endocrinologists should be alert to its clinical signs and promptly diagnose and treat PDB before it results in irreversible complications, such as deformity, fracture or neurological sequelae. Most commonly, PDB is suspected upon the incidental finding of elevated serum alkaline phosphatase levels or a radiographic abnormality in an otherwise healthy individual above 55 years of age. Some of these individuals may have symptoms such as bone pain or enlargement with increased warmth. In general, a basic laboratory evaluation of bone metabolism, plain radiographies of affected bones and bone scintigraphy are sufficient to corroborate the diagnosis. Antiresorptive therapy with bisphosphonates is the mainstay of treatment of symptomatic PDB, and intravenous zoledronic acid has emerged as an effective and safe treatment option, leading to sustained remission and improved quality of life. It is extremely important, though, to ensure calcium and vitamin D sufficiency before and during treatment in order to prevent hypocalcemia. The benefit of treating all asymptomatic patients is not clear, but treatment is warranted if the pagetic lesion is located in a site where progression to fracture, deformity, or compression would significantly impair the patient quality of life. This mini-review focuses on important aspects of the diagnosis and treatment of PDB.

Symptomatic intracranial hypertension and prolonged hypocalcemia following treatment of Paget's disease of the skull with zoledronic acid

Skull involvement in Paget's disease of bone can lead to neurological symptoms, prompting treatment. Intravenous zoledronic acid (ZA) has emerged as an effective and safe treatment option for patients with Paget's, leading to sustained remission and improved quality of life. A previously untreated 61-year-old female presented with 2-year history of facial asymmetry with progressive hearing impairment. Serum calcium levels were normal with upper normal levels of PTH and low 25OHD levels. Serum alkaline phosphatase was markedly increased and bone scan showed extensive pagetic involvement of the skull. Head CT and MRI revealed hydrocephalus with cerebellar tonsillar herniation, platybasia and basilar invagination. In the absence of clinical signs or symptoms of intracranial hypertension, she was treated with intravenous ZA after 15-day supplementation with calcium and vitamin D. Twelve hours after the infusion, the patient became confused, agitated and disoriented and developed urinary incontinence; cortical sulci became effaced on CT indicating increased intracranial pressure. Over the following days, she developed frank hypocalcemia requiring intravenous calcium infusion and calcitriol. Neurological status returned to normal within 24 h of onset, except for urinary incontinence. Nine months later she remained incontinent and still required calcitriol to maintain normocalcemia. Zoledronic acid is a first-line option for the treatment of Paget's disease, yet there can be complications in particular clinical scenarios such as pagetic hydrocephalus, as seen in this case. Plentiful supplementation of calcium and vitamin D before bisphosphonate therapy is paramount in order to minimize the risk of prolonged post-treatment hypocalcemia.

Paget's Disease of Bone: A Review of Epidemiology, Pathophysiology and Management

Paget's disease of bone is a common disorder which may affect one or many bones. Although many patients are asymptomatic, a variety of symptoms and complications may occur. Fortunately, effective pharmacologic therapy, primarily with potent bisphosphonates, is now available to treat patients with complications or symptoms. This review of Paget's disease of bone will include epidemiology and pathophysiology, complications and clinical findings, indications for treatment, and the drugs currently available to treat this condition.

Imaging of Paget disease of bone and its musculoskeletal complications: self-assessment module

The educational objectives for this self-assessment module are for the participant to exercise, self-assess, and improve his or her skills in diagnostic radiology with regard to imaging of Paget disease of bone and its musculoskeletal complications.

Demographic and Clinical Features Related to a Symptomatic Onset of Paget’s Disease of Bone

Objective.

Paget’s disease of bone (PDB) is a focal disorder of skeletal remodeling that can lead to bone pain, deformity, and fractures, but it can often be asymptomatic for a long time. This study investigated which factors may distinguish patients with clinical manifestations from asymptomatic patients.

Methods.

The study group consisted of 224 patients with PDB referred to our Bone Disease Unit. For all patients, data were collected about clinical and demographic variables and diagnostic procedures. Logistic regression analyses were used to assess the role of recorded variables on the odds of being diagnosed clinically rather than by chance.

Results.

Among the 124 patients with clinical manifestations leading to the diagnosis (55.4%), 36 subjects complained of bone pain, 32 articular pain, 42 back pain, 2 headache; 9 had fractures in Paget bone, and 3 had bone deformity. In 100 patients (44.6%) PDB was diagnosed by chance. At the multivariate analysis, only the number of bones involved (OR for 1 site increment = 1.18, 95% CI: 1.007–1.402; p = 0.04) acted as an independent predictor for a clinical diagnosis. Some skeletal localizations were associated with a clinical diagnosis: the involvement of lumbar spine (OR = 2.085, 95% CI: 1.024–4.224; p = 0.043) was more likely in symptomatic patients; pelvis and tibia showed a borderline statistical significance. The skull was predictive for asymptomatic PDB.

Conclusion.

A systematic laboratory screening including serum alkaline phosphatase of an older subject complaining of bone pain, articular pain, or back pain is the sole strategy to improve the diagnostic sensitivity for PDB.

Neurologic complications of Paget disease of bone

OBJECTIVE

To review the epidemiology, evaluation, and management of the neurologic complications associated with Paget disease of bone (PDB).

METHODS

We reviewed the English-language medical literature using MEDLINE data sources from 1950 to August 2008 and manually searched cross-references from original articles and reviews. Search terms included "Paget* disease of bone" and "neurologic* complications," "cranial nerve," "spinal cord," or "peripheral nerve."

RESULTS

Several neurologic problems in the central and peripheral nervous systems may complicate PDB. Up to 76% of patients may have some form of neurologic involvement. Neurologic complications can occur in patients with a long history of PDB as well as in patients with previously unrecognized disease. The primary mechanisms of nerve damage in PDB involving the spine are ischemic myelitis and compression due to bone hypertrophy. Evaluation includes determining the serum alkaline phosphatase level and imaging by radiography, bone scintigraphy, computed tomographic scanning, and, for lesions of the central nervous system, magnetic resonance imaging. If a soft-tissue mass is found, biopsy should be considered to exclude the presence of sarcoma. Treatment strategies include calcium, vitamin D, bisphosphonates, and possibly surgical intervention for refractory cases.

CONCLUSION

Neurologic sequelae of PDB may be underappreciated. Despite the paucity of data guiding treatment, zoledronic acid is a reasonable first-line therapy. Lack of response to treatment or relapse should prompt diagnostic reevaluation with a heightened suspicion for tumor.

Morbidity and mortality associated with Paget's disease of bone: a population-based study

INTRODUCTION

Limited information is available about the clinical features of Paget's disease of bone among unselected patients in the community. We examined morbidity and mortality associated with this condition in a large inception cohort of Olmsted County, MN, residents with a new diagnosis of Paget's disease from 1950 through 1994.

MATERIALS AND METHODS

Survival was estimated using the Kaplan-Meier method. Cox proportional hazards models were used to assess the impact of various covariates on death.

RESULTS

Paget's disease of bone was diagnosed in 236 Olmsted County residents (mean age at diagnosis, 69.6 yr; 55% men). The majority were symptomatic at diagnosis (58%), and the proportion with symptoms did not change from the prescreening era (1950 to June 1974) to the postscreening era (July 1974-1994). Most patients had polyostotic disease (72%), and the pelvis (67%), vertebra (41%), and femur (31%) were the most common sites of involvement. Skeletal complications attributable to Paget's disease included bowing deformities (7.6%), fracture of pagetic bone (9.7%), and osteosarcoma (0.4%). Osteoarthritis was observed in 73% of patients, and 11% had a hip or knee replacement. Nonskeletal complications related to Paget's disease included cranial nerve (0.4%), peripheral nerve (1.7%), and nerve root (3.8%) compression, basilar invagination (2.1%), hypercalcemia (5.2%), and congestive heart failure (3.0%). Hearing loss, noted in 61%, was significantly higher than previously reported.

CONCLUSIONS

Compared with white Minnesota residents, overall survival was slightly better than expected (p = 0.010). No clinical risk factors were identified that were associated with an increased risk of death.