Two cases of sporadic adult-onset neuronal intranuclear inclusion disease preceded by urinary disturbance for many years

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disease defined by the presence of eosinophilic hyaline intranuclear inclusions. The initial and main clinical feature of adult-onset NIID is predominantly dementia. We present herein 2 cases of sporadic adult-onset NIID with longstanding urinary disturbance prior to development of other neurological symptoms. Case 1: A 71-year-old woman was admitted after she lost consciousness while bathing. She presented slowly progressive bladder dysfunction starting at the age of 40. Recently, she complained of recurrent light-headedness on standing. Her neurological findings showed miosis, muscle weakness, rigidity, hyporeflexia, sensory disturbance, cerebellar ataxia, and orthostatic hypotension. Case 2: A 68-year-old man was admitted because of episodes of transient loss of consciousness. Ten years earlier, he had developed urinary dysfunction. His neurological findings revealed cognitive dysfunction, cerebellar ataxia, and hyporeflexia. Both patients had leukoencephalopathy and motor-sensory neuropathy. In both cases, diffusion-weighted imaging showed high-intensity signals in the corticomedurally junction; and skin biopsy samples revealed ubiquitin-positive intranuclear inclusions. Therefore, we made a diagnosis of adult-onset NIID. Although numerous cases of this disorder have been reported in the past, there were only a few cases showing the development of other neurological symptoms after longstanding urinary disturbance. Our cases suggest that it is worthwhile considering the possibility of NIID in cases with a long-term history of neurogenic bladder dysfunction.