Differential Diagnosis

The patient's presentation of dementia, shuffling gait, urinary incontinence, and ventriculomegaly on CT brain scan without a history of meningitis, followed by the development of forgetfulness, suggests a neurological condition. Here's a categorized differential diagnosis:

• Single most likely diagnosis

  • B. Normal tension hydrocephalus: This condition is characterized by the triad of gait disturbance, dementia, and urinary incontinence, along with ventriculomegaly on imaging, which matches the patient's presentation. The absence of a past history of meningitis and the presence of ventriculomegaly without significant cortical atrophy support this diagnosis.

• Other Likely diagnoses

  • A. Frontotemporal dementia: Although frontotemporal dementia can present with dementia and changes in gait, it typically does not cause significant ventriculomegaly. However, it remains a consideration due to the patient's dementia.
  • C. Creutzfeldt Jakob disease: This is a prion disease that can cause rapid progression of dementia, along with gait disturbances and other neurological symptoms. However, it is less likely given the slower progression and the specific combination of symptoms described.

• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)

  • None specifically fit into this category as "do not miss" diagnoses that are both unlikely and potentially deadly if missed, given the provided options. However, conditions like Creutzfeldt Jakob disease could be considered here due to its rapid progression and fatal outcome, even though it's already listed under other likely diagnoses.

• Rare diagnoses

  • D. Huntington disease: This is an autosomal dominant neurodegenerative disorder characterized by chorea, psychiatric symptoms, and cognitive decline. While it can cause gait disturbances and dementia, the specific combination of symptoms and the absence of chorea or a family history make it less likely in this case.
  • Other rare conditions that could present with similar symptoms, such as certain storage diseases or leukodystrophies, are not listed among the options but could be considered in a broader differential diagnosis.