Detection of hearing impairment and handicap in Paget's disease of bone using a simple scoring system: a case control study

CT Assessment of Otic Capsule Bone Density in Paget's Disease of the Temporal Bone and Its Relationship With Hearing Loss

OBJECTIVES

To study computed tomography findings in Paget's disease of temporal bone (PDTB) and analyze the relations between otic capsule bone mineral density values measured in Hounsfield Units (HU) and hearing loss (HL).

STUDY DESIGN

Observational case-control study.

SETTING

Tertiary referral center.

PATIENTS

Radiographically confirmed PDTB cases and control group.

INTERVENTION

Diagnostic.

MAIN OUTCOME MEASURES

Hearing thresholds and computed tomography bone density values.

RESULTS

Twenty-three ears in the case group (PDTB) and 27 control ears were included. In the PDTB group, HL was found in 87% of the ears (43% mixed) and an air-conduction threshold of 50.7 dB (SD = 19.8). In the control group, 48% of the ears showed HL (7% mixed) and an air-conduction threshold of 34.5 dB (SD = 20.6) was found; the difference was statistically significant (p < 0.05). Measurements of bone density (HU) in the otic capsule (regions of interest [ROI] 1 and 2) and in the petrous bone (ROI 3) were significantly lower (p < 0.05) in the PDTB group than in controls.The PDTB group presented a significant association between otic capsule bone density in ROI 1 and mean otic capsule density with air and bone-conduction thresholds (p < 0.05). In controls, no association was observed between any density value and audiometric thresholds.

CONCLUSION

PDTB patients showed more frequent HL, lower thresholds, and a higher proportion of mixed HL than controls. Bone density (HU) was decreased in all ROIs in PDTB patients in comparison with controls. Bone density in the otic capsule was associated with HL in PDTB patients, but no association was observed between bone density and HL in controls.

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.

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.