Differential Diagnosis

The patient's presentation of progressive memory loss, personality changes, and CT findings of hyper-intensity can be approached by considering the following categories:

• Single Most Likely Diagnosis

  • D. Alzheimer's Disease: This is the most common cause of dementia in the elderly, characterized by progressive memory loss. The patient's 2-year history of slow and progressive memory loss, along with changes in personality, such as becoming aggressive, are consistent with Alzheimer's disease. The CT findings of hyper-intensity could be indicative of atrophy or other changes associated with Alzheimer's.

• Other Likely Diagnoses

  • A. Multi-vascular Dementia: This condition is the second most common cause of dementia and is characterized by cognitive decline due to vascular disease. While the patient's history does not specifically mention vascular risk factors or step-wise progression typical of vascular dementia, it remains a consideration, especially given the CT findings which could indicate vascular changes.
  • C. Mixed Dementia: This diagnosis refers to the coexistence of Alzheimer's disease and vascular dementia. Given the patient's age and the combination of progressive memory loss with possible vascular changes on CT, mixed dementia is a plausible diagnosis.

• Do Not Miss Diagnoses

  • B. Major Depression: Although less likely given the progressive nature of the symptoms and the CT findings, major depression, especially in the elderly, can present with cognitive symptoms mimicking dementia (pseudodementia). It's crucial to rule out depression as it is treatable and can significantly impact the patient's quality of life.
  • Normal Pressure Hydrocephalus (NPH): Not listed among the options but important to consider in the differential diagnosis of dementia, especially if there are symptoms of gait disturbance and urinary incontinence, which are not mentioned here. NPH can cause cognitive decline, and its diagnosis is critical because it is potentially treatable with shunting.

• Rare Diagnoses

  • Frontotemporal Dementia (FTD): Characterized by significant changes in personality, behavior, and language early in the disease, with memory affected later. The patient's recent change in personality could suggest FTD, but the 2-year history of progressive memory loss makes this less likely.
  • Other rare causes of dementia, such as Creutzfeldt-Jakob disease, should be considered if the progression is very rapid or if there are other distinctive features such as myoclonus or specific MRI findings. However, these are less likely given the slow progression and the information provided.