Clinical Reasoning: A 75-Year-Old Man With Dementia, Incontinence, and Gait Dysfunction.

Idiopathic normal pressure hydrocephalus (iNPH) is a progressive neurological disorder characterized by gait apraxia, cognitive decline, and urinary incontinence. It can be difficult to diagnose iNPH as the symptoms may overlap with other neurodegenerative diseases including ​cervical spondylotic myelopathy. Cervical spondylotic myelopathy is a progressive degenerative disease in which compression of the cervical spinal cord causes gait disturbances and imbalance, loss of dexterity and strength in the hands, and, at late stages, urinary dysfunction. As with iNPH, increased age is associated with higher incidence and prevalence. Surgical decompression of the cervical spinal cord is the treatment of choice in patients with progressive myelopathy. Accordingly, iNPH and cervical myelopathy may both present with progressive gait impairment and incontinence, especially in the elderly. The case presented here demonstrates that both iNPH and cervical myelopathy may present simultaneously and result in gait disturbances and imbalance in some patients. For patients with suspected iNPH and myelopathic findings on examination, it is prudent to obtain a cervical spine MRI to assess for cervical stenosis. Moreover, cervical stenosis can mask the effect of cerebrospinal fluid diversion in patients with comorbid iNPH and cervical myelopathy. Therefore, the differential for patients who have symptomology suggestive of iNPH should include cervical spine myelopathy, with considerations for possible cervical decompression in addition to placement of a ventriculoperitoneal shunt.