An uncommon cause of headache and hearing loss

Abstract

Imaging demonstrated diffuse thickening of the skull with illdefined patchy sclerosis on skull X-ray. CT and MRI demonstrated diffuse textural abnormality of the calvarium and skull base suggestive of fibrous dysplasia or Paget’s disease. Bilateral narrowing of the internal auditory canals was also identified (Fig. 1), as was basilar invagination. Baseline bloods were performed with a markedly elevated ALP (2000 IU/L). A biopsy was performed of the skull, which demonstrated lamellar bone with irregular curliform cement lines with evidence of active bone resorption and bone remodelling. Additionally the marrow demonstrated increased fibrosis. These findings were consistent with Paget’s disease of bone. The patient was referred to an endocrinologist and commenced on the biphosphonate zoledronic acid, initially intravenously and later orally with good effect. Paget’s disease of bone is a chronic inflammatory disease of the bone affecting 1 to 2% of the population. This condition was first described in 1877 by Sir James Paget. Although most patients are asymptomatic, in 10–30% it is characterised by pain, skeletal deformity, pathological fractures and high-output congestive cardiac failure. Most patients affected are over 50 years of age and there is a slight male predominance. Paget’s disease can affect any bone but is more likely to affect the axial skeleton (spine, pelvis, femur, sacrum and skull). The aetiology of this condition remains unknown, however some literature suggests involvement of paramyxovirus infection and a genetic predisposition to the condition. Paget’s disease of the skull has been reported to cause headache, abnormal skull enlargement, deformity, and hearing loss (due to compression of the 8th cranial nerve). Additional neurological deficits associated with cranial nerve compression have also been reported. There have been a number of reports of extradural haematoma and it has been postulated that this may be partly due to the increased vascularity of bone affected by Paget’s disease.